A very strong halogenated derivative of acetic acid. It is used in acid catalyzed reactions, especially those where an ester is cleaved in peptide synthesis.
Derivatives of acetic acid with one or more fluorines attached. They are almost odorless, difficult to detect chemically, and very stable. The acid itself, as well as the derivatives that are broken down in the body to the acid, are highly toxic substances, behaving as convulsant poisons with a delayed action. (From Miall's Dictionary of Chemistry, 5th ed)
Compounds used extensively as acetylation, oxidation and dehydrating agents and in the modification of proteins and enzymes.
Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.
A strong corrosive acid that is commonly used as a laboratory reagent. It is formed by dissolving hydrogen chloride in water. GASTRIC ACID is the hydrochloric acid component of GASTRIC JUICE.
A chromatography technique in which the stationary phase is composed of a non-polar substance with a polar mobile phase, in contrast to normal-phase chromatography in which the stationary phase is a polar substance with a non-polar mobile phase.
A mass spectrometry technique used for analysis of nonvolatile compounds such as proteins and macromolecules. The technique involves preparing electrically charged droplets from analyte molecules dissolved in solvent. The electrically charged droplets enter a vacuum chamber where the solvent is evaporated. Evaporation of solvent reduces the droplet size, thereby increasing the coulombic repulsion within the droplet. As the charged droplets get smaller, the excess charge within them causes them to disintegrate and release analyte molecules. The volatilized analyte molecules are then analyzed by mass spectrometry.
Determination of the spectra of ultraviolet absorption by specific molecules in gases or liquids, for example Cl2, SO2, NO2, CS2, ozone, mercury vapor, and various unsaturated compounds. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.
An analytical method used in determining the identity of a chemical based on its mass using mass analyzers/mass spectrometers.
Liquids that dissolve other substances (solutes), generally solids, without any change in chemical composition, as, water containing sugar. (Grant & Hackh's Chemical Dictionary, 5th ed)
Cyanogen bromide (CNBr). A compound used in molecular biology to digest some proteins and as a coupling reagent for phosphoroamidate or pyrophosphate internucleotide bonds in DNA duplexes.
Substances used for the detection, identification, analysis, etc. of chemical, biological, or pathologic processes or conditions. Indicators are substances that change in physical appearance, e.g., color, at or approaching the endpoint of a chemical titration, e.g., on the passage between acidity and alkalinity. Reagents are substances used for the detection or determination of another substance by chemical or microscopical means, especially analysis. Types of reagents are precipitants, solvents, oxidizers, reducers, fluxes, and colorimetric reagents. (From Grant & Hackh's Chemical Dictionary, 5th ed, p301, p499)
Chromatographic techniques in which the mobile phase is a liquid.
Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are linear polypeptides that are normally synthesized on RIBOSOMES.
Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.
A technique for causing a targeted loss of molecular function from REACTIVE OXYGEN SPECIES that are formed by the illumination of dyes placed in the immediate vicinity of the target molecule.
A mass spectrometric technique that is used for the analysis of large biomolecules. Analyte molecules are embedded in an excess matrix of small organic molecules that show a high resonant absorption at the laser wavelength used. The matrix absorbs the laser energy, thus inducing a soft disintegration of the sample-matrix mixture into free (gas phase) matrix and analyte molecules and molecular ions. In general, only molecular ions of the analyte molecules are produced, and almost no fragmentation occurs. This makes the method well suited for molecular weight determinations and mixture analysis.
Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.

Clinical isoflurane metabolism by cytochrome P450 2E1. (1/125)

BACKGROUND: Some evidence suggests that isoflurane metabolism to trifluoroacetic acid and inorganic fluoride by human liver microsomes in vitro is catalyzed by cytochrome P450 2E1 (CYP2E1). This investigation tested the hypothesis that P450 2E1 predominantly catalyzes human isoflurane metabolism in vivo. Disulfiram, which is converted in vivo to a selective inhibitor of P450 2E1, was used as a metabolic probe for P450 2E1. METHODS: Twenty-two elective surgery patients who provided institutionally-approved written informed consent were randomized to receive disulfiram (500 mg orally, N = 12) or nothing (controls, N = 10) the evening before surgery. All patients received a standard isoflurane anesthetic (1.5% end-tidal in oxygen) for 8 hr. Urine and plasma trifluoroacetic acid and fluoride concentrations were quantitated in samples obtained for 4 days postoperatively. RESULTS: Patient groups were similar with respect to age, weight, gender, duration of surgery, blood loss, and delivered isoflurane dose, measured by cumulative end-tidal isoflurane concentrations (9.7-10.2 MAC-hr). Postoperative urine excretion of trifluoroacetic acid (days 1-4) and fluoride (days 1-3) was significantly (P<0.05) diminished in disulfiram-treated patients. Cumulative 0-96 hr excretion of trifluoroacetic acid and fluoride in disulfiram-treated patients was 34+/-72 and 270+/-70 micromoles (mean +/- SD), respectively, compared to 440+/-360 and 1500+/-800 micromoles in controls (P<0.05 for both). Disulfiram also abolished the rise in plasma metabolite concentrations. CONCLUSIONS: Disulfiram, a selective inhibitor of human hepatic P450 2E1, prevented 80-90% of isoflurane metabolism. These results suggest that P450 2E1 is the predominant P450 isoform responsible for human clinical isoflurane metabolism in vivo.  (+info)

Identification of natural antigenic peptides of a human gastric signet ring cell carcinoma recognized by HLA-A31-restricted cytotoxic T lymphocytes. (2/125)

Peptides of human melanomas recognized by CD8+ CTLs have been identified, but the nature of those of nonmelanoma tumors remains to be elucidated. Previously, we established a gastric signet ring cell carcinoma HST-2 and HLA-A31 (A*31012)-restricted autologous CTL clone, TcHST-2. In the present study, we determined the natural antigenic peptides of HST-2 cells. The purified preparation of acid-extracted Ags was submitted to the peptide sequencer, and one peptide, designated F4.2 (Tyr-Ser-Trp-Met-Asp-Ile-Ser-Cys-Trp-Ile), appeared to be immunogenic. To confirm the antigenicity of F4.2 further, we constructed an expression minigene vector (pF4.2ss) coding adenovirus E3, a 19-kDa protein signal sequence plus F4.2. An introduction of pF4.2ss minigene to HST-2 and HLA-A31(+) allogeneic tumor cells clearly enhanced and induced the TcHST-2 reactivity, respectively. Furthermore, when synthetic peptides of F4.2 C-terminal-deleted peptides were pulsed to HST-2 cells, F4.2-9 (nonamers), but not F4.2-8 or F4.2-7 (octamer or heptamer, respectively), enhanced the reactivity of TcHST-2, suggesting that the N-terminal ninth Trp might be a T cell epitope. This was confirmed by lack of antigenicity when using synthetic substituted peptides as well as minigenes coding F4.2 variant peptides with Ala or Arg at the ninth position of F4.2. Meanwhile, it was indicated that the sixth position Ile was critically important for the binding to HLA-A31 molecules. Thus, our data indicate that F4.2 may work as an HLA-A31-restricted natural antigenic peptide recognized by CTLs.  (+info)

Trifluoroacetate, a contaminant in purified proteins, inhibits proliferation of osteoblasts and chondrocytes. (3/125)

Peptides purified by HPLC are often in the form of a trifluoroacetate (TFA) salt, because trifluoroacetic acid is used as a solvent in reversed-phase HPLC separation. However, the potential effects of this contaminant in culture systems have not been addressed previously. TFA (10(-8) to 10(-7) M) reduced cell numbers and thymidine incorporation into fetal rat osteoblast cultures after 24 h. Similar effects were found in cultures of articular chondrocytes and neonatal mouse calvariae, indicating that the effect is not specific to one cell type or to one species of origin. When the activities of the TFA and hydrochloride salts of amylin, amylin-(1-8), and calcitonin were compared in osteoblasts, cell proliferation was consistently less with the TFA salts of these peptides, resulting in failure to detect a proliferative effect or wrongly attributing an antiproliferative effect. This finding is likely to be relevant to all studies of purified peptides in concentrations above 10(-9) M in whatever cell or tissue type. Such peptides should be converted to a hydrochloride or biologically equivalent salt before assessment of their biological effects is undertaken.  (+info)

Quantitative screening for benzodiazepines in blood by dual-column gas chromatography and comparison of the results with urine immunoassay. (4/125)

A dual-column retention index method is described for quantitative gas chromatographic (GC) screening of 26 benzodiazepine drugs and metabolites in the blood using DB-5 and DB-17 capillary columns and electron capture detection. The method involves a one-step, small-scale liquid-liquid extraction with ethyl acetate and derivatization with N-methyl-N-(tert-butyldimethylsilyl)trifluoroacetamide with 1% tert-butyldimethylsilyl chloride. The results from the GC screening of 514 postmortem blood samples were compared to those obtained from urine immunoassay (Syva ETSplus with a 200-ng/mL cutoff). Both methods gave a negative result in 284 cases and a positive result in 149 cases. In 48 cases, urine was negative by immunoassay but blood was positive by GC. The opposite situation (blood negative, urine positive) was detected only in four cases. In 29 cases, an invalid result was obtained by urine by immunoassay: 26 blood samples of those cases were negative and three samples positive by GC. In postmortem forensic toxicology, the present GC method seems to be a good alternative to the common combination of urinary immunoassay followed by quantitative analysis of blood by chromatography.  (+info)

Tumor-specific CD4+ T lymphocytes from cancer patients are required for optimal induction of cytotoxic T cells against the autologous tumor. (5/125)

This study focuses on the specific CD4+ T cell requirement for optimal induction of cytotoxicity against MHC class II negative autologous tumors (AuTu) collected from patients with various types of cancer at advanced stages. CD4+ T cells were induced in cultures of cancer patients' malignant effusion-associated mononuclear cells with irradiated AuTu (mixed lymphocyte tumor cultures (MLTC)) in the presence of recombinant IL-2 and recombinant IL-7. Tumor-specific CD4+ T cells did not directly recognize the AuTu cells, but there was an MHC class II-restricted cross-priming by autologous dendritic cells (DCs), used as APC. CD8+ CTL, also induced during the MLTC, lysed specifically AuTu cells or DCs pulsed with AuTu peptide extracts (acid wash extracts (AWE)) in an MHC class I-restricted manner. Removal of CD4+ T cells or DCs from the MLTC drastically reduced the CD8+ CTL-mediated cytotoxic response against the AuTu. AWE-pulsed DCs preincubated with autologous CD4+ T cells were able, in the absence of CD4+ T cells, to stimulate CD8+ T cells to lyse autologous tumor targets. Such activated CD8+ T cells produced IL-2, IFN-gamma, TNF-alpha, and GM-CSF. The process of the activation of AWE-pulsed DCs by CD4+ T cells could be inhibited with anti-CD40 ligand mAb. Moreover, the role of CD4+ T cells in activating AWE-pulsed DCs was undertaken by anti-CD40 mAb. Our data demonstrate for the first time in patients with metastatic cancer the essential role of CD4+ Th cell-activated DCs for optimal CD8+ T cell-mediated killing of autologous tumors and provide the basis for the design of novel protocols in cellular adoptive immunotherapy of cancer, utilizing synthetic peptides capable of inducing T cell help in vivo.  (+info)

Analysis for carbamate insecticides and metabolites. (6/125)

Of the more conventional pesticidal chemicals, the carbamate insecticides pose some unique problems relative to residue analysis. Most of these compounds are unstable under conditions normally used for GLC analysis and require special attention if this technique is to apply to the carbamates. Moreover, the carbamates are commonly metabolized to products which are toxicologically significant and which must be included in any analytical considerations. These and other problems inherent in carbamate residue methodology are discussed in this report along with technique currently utilized or having potential as sound procedures for the analyses of carbamate insecticides.  (+info)

Urinary metabolites of halothane in man. (7/125)

The urinary metabolites of halothane (2-bromo-2-chloro-1,1,1-trifluoroethane) were investigated in five individuals given trace doses (25 muCi), and in three individuals given large doses (1 mCi) of radioactively labeled 14C-halothane. The latter were donor subjects for heart transplant operations. Separation of the nonvolatile urinary metabolites of halothane was accomplished by chemical extraction, electrophoresis, ion-exchange and high-pressure liquid chromatography, and gas chromatography. Identification of the individual metabolites was by nuclear magnetic resonance and mass spectrometry. Three major metabolites were identified: trifluoroacetic acid, N-trifluoroacetyl-2-aminoethanol, and N-acetyl-S-(2-bromo-2-chloro-1,1-difluoroethyl)-L-cysteine. Smaller unidentified radioactive peaks were also found. The presence of both ethanolamide and cysteine conjugates of halothane is of concern. These urinary products imply the presence of reactive intermediates. The conjugation of such intermediates to proteins and phospholipids may give rise to the high-molecular-weight covalently bound metabolites demonstrated to be present in the liver following halothane anesthesia. Elucidation of the structures of the urinary metabolites provides information important to an understanding of halothane metabolism and its potential hepatotoxicity.  (+info)

Acid mediated hydrolysis of blueberry anthocyanins. (8/125)

Acid mediated hydrolysis of anthocyanins was studied using capillary zone electrophoresis (CZE). A commercially available wild blueberry (Bilberry) extract was dissolved in different concentrations of TFA (0.1, 1, 3, 9%), then was subjected to thermodecomposition reaction at 95 degrees C. After the reaction, the samples were analyzed by CZE. The hydrolysis rate of each anthocyanin and the formation of the aglycon were determined by the change in the peak pattern of the anthocyanins in the electropherogram. Each anthocyanin peak decreased time dependently in a first order kinetic fashion. It was revealed that the hydrolysis rate of each anthocyanin was determined primarily by the type of conjugated sugar and not by the aglycon structure. The rate constant of anthocyanin hydrolysis was in the following order, arabinoside>galactoside>glucoside without regard to the aglycon structure. The kinetic behavior of this anthocyanin hydrolysis together with the CZE mobility allowed us to identify an unknown CZE peak as delphinidin 3-O-beta-arabinoside. At low TFA concentration, significant decomposition of the anthocyanidin nucleus occurred, but the glycoside hydrolysis predominated at high TFA concentration. It was further revealed that the aglycon released reacted successively to form polymeric products at higher TFA conditions.  (+info)

Trifluoroacetic acid (TFA) is not typically considered a medical term, but rather a chemical one. However, it does have relevance to the medical field in certain contexts, such as in laboratory settings or pharmaceutical manufacturing. Here's a definition of TFA:

Trifluoroacetic acid (C2HF3O2) is an inorganic compound that is a colorless liquid at room temperature. It has a strong, pungent odor and is highly corrosive. In the chemical industry, it is commonly used as a reagent or solvent due to its ability to dissolve a wide range of organic compounds.

In the medical field, TFA may be encountered in laboratory settings where it can be used for various purposes such as peptide synthesis, chromatography, and other chemical reactions. It is also sometimes used as an ingredient in certain pharmaceutical formulations, although its use is generally limited due to its potential toxicity.

It's worth noting that TFA is not a medication or drug, but rather a chemical compound with various industrial and laboratory applications.

Fluoroacetates are organic compounds that contain a fluorine atom and an acetic acid group. The most well-known and notorious compound in this family is sodium fluoroacetate, also known as 1080 or compound 1080, which is a potent metabolic poison. It works by interfering with the citric acid cycle, a critical process that generates energy in cells. Specifically, fluoroacetates are converted into fluorocitrate, which inhibits an enzyme called aconitase, leading to disruption of cellular metabolism and ultimately cell death.

Fluoroacetates have been used as rodenticides and pesticides, but their use is highly regulated due to their high toxicity to non-target species, including humans. Exposure to fluoroacetates can cause a range of symptoms, including nausea, vomiting, seizures, and cardiac arrest, and can be fatal if not treated promptly.

Acetic anhydride is a chemical compound with the formula (CH3CO)2O. It is a colorless liquid that is used as a reagent in organic synthesis, particularly in the production of cellulose acetate and other acetate esters. Acetic anhydride is also an important intermediate in the synthesis of certain pharmaceuticals and dyes.

In medical terminology, acetic anhydride is not typically used as a diagnostic or therapeutic agent. However, it can be used in laboratory settings to synthesize compounds that may have medical applications. For example, acetic anhydride has been used to produce certain antiviral drugs and antibiotics.

It is important to note that acetic anhydride can be harmful or fatal if swallowed, inhaled, or absorbed through the skin. It can cause burns and eye damage, and may be harmful to the respiratory system if inhaled. Therefore, it should be handled with care and used only in well-ventilated areas with appropriate personal protective equipment.

High-performance liquid chromatography (HPLC) is a type of chromatography that separates and analyzes compounds based on their interactions with a stationary phase and a mobile phase under high pressure. The mobile phase, which can be a gas or liquid, carries the sample mixture through a column containing the stationary phase.

In HPLC, the mobile phase is a liquid, and it is pumped through the column at high pressures (up to several hundred atmospheres) to achieve faster separation times and better resolution than other types of liquid chromatography. The stationary phase can be a solid or a liquid supported on a solid, and it interacts differently with each component in the sample mixture, causing them to separate as they travel through the column.

HPLC is widely used in analytical chemistry, pharmaceuticals, biotechnology, and other fields to separate, identify, and quantify compounds present in complex mixtures. It can be used to analyze a wide range of substances, including drugs, hormones, vitamins, pigments, flavors, and pollutants. HPLC is also used in the preparation of pure samples for further study or use.

Hydrochloric acid, also known as muriatic acid, is not a substance that is typically found within the human body. It is a strong mineral acid with the chemical formula HCl. In a medical context, it might be mentioned in relation to gastric acid, which helps digest food in the stomach. Gastric acid is composed of hydrochloric acid, potassium chloride and sodium chloride dissolved in water. The pH of hydrochloric acid is very low (1-2) due to its high concentration of H+ ions, making it a strong acid. However, it's important to note that the term 'hydrochloric acid' does not directly refer to a component of human bodily fluids or tissues.

Reverse-phase chromatography is a type of liquid chromatography that is commonly used in analytical chemistry and biochemistry to separate, identify, and purify complex mixtures of chemicals or biological molecules. In this technique, the stationary phase is a nonpolar solid, such as octadecyl silica (ODS) or C18, which is coated with a polar solvent, while the mobile phase is a nonpolar solvent, such as methanol or acetonitrile.

The term "reverse-phase" refers to the fact that the polarity of the stationary and mobile phases is reversed compared to normal-phase chromatography. In normal-phase chromatography, the stationary phase is polar and the mobile phase is nonpolar, which results in the separation of analytes based on their polarity. However, in reverse-phase chromatography, the stationary phase is nonpolar and the mobile phase is polar, which means that the separation of analytes is based on their hydrophobicity or hydrophilicity.

In reverse-phase chromatography, hydrophobic molecules elute more slowly than hydrophilic molecules because they have a stronger affinity for the nonpolar stationary phase. The retention time of an analyte can be adjusted by changing the composition of the mobile phase or the pH of the solution. This technique is widely used in the analysis of drugs, metabolites, peptides, proteins, and other biological molecules.

Mass spectrometry with electrospray ionization (ESI-MS) is an analytical technique used to identify and quantify chemical species in a sample based on the mass-to-charge ratio of charged particles. In ESI-MS, analytes are ionized through the use of an electrospray, where a liquid sample is introduced through a metal capillary needle at high voltage, creating an aerosol of charged droplets. As the solvent evaporates, the analyte molecules become charged and can be directed into a mass spectrometer for analysis.

ESI-MS is particularly useful for the analysis of large biomolecules such as proteins, peptides, and nucleic acids, due to its ability to gently ionize these species without fragmentation. The technique provides information about the molecular weight and charge state of the analytes, which can be used to infer their identity and structure. Additionally, ESI-MS can be interfaced with separation techniques such as liquid chromatography (LC) for further purification and characterization of complex samples.

Spectrophotometry, Ultraviolet (UV-Vis) is a type of spectrophotometry that measures how much ultraviolet (UV) and visible light is absorbed or transmitted by a sample. It uses a device called a spectrophotometer to measure the intensity of light at different wavelengths as it passes through a sample. The resulting data can be used to determine the concentration of specific components within the sample, identify unknown substances, or evaluate the physical and chemical properties of materials.

UV-Vis spectroscopy is widely used in various fields such as chemistry, biology, pharmaceuticals, and environmental science. It can detect a wide range of substances including organic compounds, metal ions, proteins, nucleic acids, and dyes. The technique is non-destructive, meaning that the sample remains unchanged after the measurement.

In UV-Vis spectroscopy, the sample is placed in a cuvette or other container, and light from a source is directed through it. The light then passes through a monochromator, which separates it into its component wavelengths. The monochromatic light is then directed through the sample, and the intensity of the transmitted or absorbed light is measured by a detector.

The resulting absorption spectrum can provide information about the concentration and identity of the components in the sample. For example, if a compound has a known absorption maximum at a specific wavelength, its concentration can be determined by measuring the absorbance at that wavelength and comparing it to a standard curve.

Overall, UV-Vis spectrophotometry is a versatile and powerful analytical technique for quantitative and qualitative analysis of various samples in different fields.

Molecular structure, in the context of biochemistry and molecular biology, refers to the arrangement and organization of atoms and chemical bonds within a molecule. It describes the three-dimensional layout of the constituent elements, including their spatial relationships, bond lengths, and angles. Understanding molecular structure is crucial for elucidating the functions and reactivities of biological macromolecules such as proteins, nucleic acids, lipids, and carbohydrates. Various experimental techniques, like X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy, and cryo-electron microscopy (cryo-EM), are employed to determine molecular structures at atomic resolution, providing valuable insights into their biological roles and potential therapeutic targets.

Mass spectrometry (MS) is an analytical technique used to identify and quantify the chemical components of a mixture or compound. It works by ionizing the sample, generating charged molecules or fragments, and then measuring their mass-to-charge ratio in a vacuum. The resulting mass spectrum provides information about the molecular weight and structure of the analytes, allowing for identification and characterization.

In simpler terms, mass spectrometry is a method used to determine what chemicals are present in a sample and in what quantities, by converting the chemicals into ions, measuring their masses, and generating a spectrum that shows the relative abundances of each ion type.

Solvents, in a medical context, are substances that are capable of dissolving or dispersing other materials, often used in the preparation of medications and solutions. They are commonly organic chemicals that can liquefy various substances, making it possible to administer them in different forms, such as oral solutions, topical creams, or injectable drugs.

However, it is essential to recognize that solvents may pose health risks if mishandled or misused, particularly when they contain volatile organic compounds (VOCs). Prolonged exposure to these VOCs can lead to adverse health effects, including respiratory issues, neurological damage, and even cancer. Therefore, it is crucial to handle solvents with care and follow safety guidelines to minimize potential health hazards.

Cyanogen bromide is a solid compound with the chemical formula (CN)Br. It is a highly reactive and toxic substance that is used in research and industrial settings for various purposes, such as the production of certain types of resins and gels. Cyanogen bromide is an alkyl halide, which means it contains a bromine atom bonded to a carbon atom that is also bonded to a cyano group (a nitrogen atom bonded to a carbon atom with a triple bond).

Cyanogen bromide is classified as a class B poison, which means it can cause harm or death if swallowed, inhaled, or absorbed through the skin. It can cause irritation and burns to the eyes, skin, and respiratory tract, and prolonged exposure can lead to more serious health effects, such as damage to the nervous system and kidneys. Therefore, it is important to handle cyanogen bromide with care and to use appropriate safety precautions when working with it.

Indicators and reagents are terms commonly used in the field of clinical chemistry and laboratory medicine. Here are their definitions:

1. Indicator: An indicator is a substance that changes its color or other physical properties in response to a chemical change, such as a change in pH, oxidation-reduction potential, or the presence of a particular ion or molecule. Indicators are often used in laboratory tests to monitor or signal the progress of a reaction or to indicate the end point of a titration. A familiar example is the use of phenolphthalein as a pH indicator in acid-base titrations, which turns pink in basic solutions and colorless in acidic solutions.

2. Reagent: A reagent is a substance that is added to a system (such as a sample or a reaction mixture) to bring about a chemical reaction, test for the presence or absence of a particular component, or measure the concentration of a specific analyte. Reagents are typically chemicals with well-defined and consistent properties, allowing them to be used reliably in analytical procedures. Examples of reagents include enzymes, antibodies, dyes, metal ions, and organic compounds. In laboratory settings, reagents are often prepared and standardized according to strict protocols to ensure their quality and performance in diagnostic tests and research applications.

Liquid chromatography (LC) is a type of chromatography technique used to separate, identify, and quantify the components in a mixture. In this method, the sample mixture is dissolved in a liquid solvent (the mobile phase) and then passed through a stationary phase, which can be a solid or a liquid that is held in place by a solid support.

The components of the mixture interact differently with the stationary phase and the mobile phase, causing them to separate as they move through the system. The separated components are then detected and measured using various detection techniques, such as ultraviolet (UV) absorbance or mass spectrometry.

Liquid chromatography is widely used in many areas of science and medicine, including drug development, environmental analysis, food safety testing, and clinical diagnostics. It can be used to separate and analyze a wide range of compounds, from small molecules like drugs and metabolites to large biomolecules like proteins and nucleic acids.

Peptides are short chains of amino acid residues linked by covalent bonds, known as peptide bonds. They are formed when two or more amino acids are joined together through a condensation reaction, which results in the elimination of a water molecule and the formation of an amide bond between the carboxyl group of one amino acid and the amino group of another.

Peptides can vary in length from two to about fifty amino acids, and they are often classified based on their size. For example, dipeptides contain two amino acids, tripeptides contain three, and so on. Oligopeptides typically contain up to ten amino acids, while polypeptides can contain dozens or even hundreds of amino acids.

Peptides play many important roles in the body, including serving as hormones, neurotransmitters, enzymes, and antibiotics. They are also used in medical research and therapeutic applications, such as drug delivery and tissue engineering.

Amino acids are organic compounds that serve as the building blocks of proteins. They consist of a central carbon atom, also known as the alpha carbon, which is bonded to an amino group (-NH2), a carboxyl group (-COOH), a hydrogen atom (H), and a variable side chain (R group). The R group can be composed of various combinations of atoms such as hydrogen, oxygen, sulfur, nitrogen, and carbon, which determine the unique properties of each amino acid.

There are 20 standard amino acids that are encoded by the genetic code and incorporated into proteins during translation. These include:

1. Alanine (Ala)
2. Arginine (Arg)
3. Asparagine (Asn)
4. Aspartic acid (Asp)
5. Cysteine (Cys)
6. Glutamine (Gln)
7. Glutamic acid (Glu)
8. Glycine (Gly)
9. Histidine (His)
10. Isoleucine (Ile)
11. Leucine (Leu)
12. Lysine (Lys)
13. Methionine (Met)
14. Phenylalanine (Phe)
15. Proline (Pro)
16. Serine (Ser)
17. Threonine (Thr)
18. Tryptophan (Trp)
19. Tyrosine (Tyr)
20. Valine (Val)

Additionally, there are several non-standard or modified amino acids that can be incorporated into proteins through post-translational modifications, such as hydroxylation, methylation, and phosphorylation. These modifications expand the functional diversity of proteins and play crucial roles in various cellular processes.

Amino acids are essential for numerous biological functions, including protein synthesis, enzyme catalysis, neurotransmitter production, energy metabolism, and immune response regulation. Some amino acids can be synthesized by the human body (non-essential), while others must be obtained through dietary sources (essential).

Chromophore-assisted light inactivation (CALI) is a photodynamic process that involves the use of a chromophore, which is a light-absorbing molecule, to specifically target and inactivate proteins or other cellular components. This technique is often used in research settings as a way to selectively eliminate specific cell populations or disrupt specific cellular processes with high spatial and temporal precision.

In CALI, the chromophore is typically linked to an antibody or other targeting molecule that specifically recognizes and binds to the protein or cellular component of interest. When the chromophore absorbs light at a specific wavelength, it undergoes a chemical reaction that generates reactive oxygen species (ROS), such as singlet oxygen or free radicals. These ROS then interact with and damage the nearby proteins or other cellular components, leading to their inactivation or destruction.

The key advantage of CALI is its ability to selectively target specific proteins or cellular components with high precision, without affecting surrounding cells or structures. This makes it a valuable tool for studying the functions of individual proteins and signaling pathways in complex biological systems. However, it is important to note that CALI can also cause non-specific damage to nearby cellular components if the chromophore is not carefully targeted or if the light dose is too high. Therefore, careful optimization and control experiments are essential for ensuring the specificity and effectiveness of CALI in any given application.

Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry (MALDI-MS) is a type of mass spectrometry that is used to analyze large biomolecules such as proteins and peptides. In this technique, the sample is mixed with a matrix compound, which absorbs laser energy and helps to vaporize and ionize the analyte molecules.

The matrix-analyte mixture is then placed on a target plate and hit with a laser beam, causing the matrix and analyte molecules to desorb from the plate and become ionized. The ions are then accelerated through an electric field and into a mass analyzer, which separates them based on their mass-to-charge ratio.

The separated ions are then detected and recorded as a mass spectrum, which can be used to identify and quantify the analyte molecules present in the sample. MALDI-MS is particularly useful for the analysis of complex biological samples, such as tissue extracts or biological fluids, because it allows for the detection and identification of individual components within those mixtures.

A peptide fragment is a short chain of amino acids that is derived from a larger peptide or protein through various biological or chemical processes. These fragments can result from the natural breakdown of proteins in the body during regular physiological processes, such as digestion, or they can be produced experimentally in a laboratory setting for research or therapeutic purposes.

Peptide fragments are often used in research to map the structure and function of larger peptides and proteins, as well as to study their interactions with other molecules. In some cases, peptide fragments may also have biological activity of their own and can be developed into drugs or diagnostic tools. For example, certain peptide fragments derived from hormones or neurotransmitters may bind to receptors in the body and mimic or block the effects of the full-length molecule.

An amino acid sequence is the specific order of amino acids in a protein or peptide molecule, formed by the linking of the amino group (-NH2) of one amino acid to the carboxyl group (-COOH) of another amino acid through a peptide bond. The sequence is determined by the genetic code and is unique to each type of protein or peptide. It plays a crucial role in determining the three-dimensional structure and function of proteins.

... is a corrosive acid but it does not pose the hazards associated with hydrofluoric acid because the carbon- ... TFA is a stronger acid than acetic acid, having an acid ionisation constant, Ka, that is approximately 34,000 times higher, as ... Fluoroacetic acid - highly toxic but naturally occurring rodenticide CH2FCOOH Difluoroacetic acid Trichloroacetic acid, the ... Trifluoroacetic acid (TFA) is an organofluorine compound with the chemical formula CF3CO2H. It is a structural analogue of ...
... (TFAA) is the acid anhydride of trifluoroacetic acid. It is the perfluorinated derivative of acetic ... Trifluoroacetic anhydride is the recommended desiccant for trifluoroacetic acid. Sigma-Aldrich Co., Trifluoroacetic Anhydride. ... Trifluoroacetic anhydride was originally prepared by the dehydration of trifluoroacetic acid with phosphorus pentoxide. The ... "Dimethyl Sulfoxide-Trifluoroacetic Anhydride. New Reagent for Oxidation of Alcohols to Carbonyls". J. Org. Chem. 41 (6): 957- ...
Perfluoroalkyl dicarboxylic acids (PFdiCAs) are also known, e.g. C2F4(CO2H)2. Trifluoroacetic acid is a widely employed acid, ... The simplest example is trifluoroacetic acid. These compounds are organofluorine analogues of ordinary carboxylic acids, but ... Perfluoroalkyl carboxylic acids (PFCAs), or perfluorocarboxylic acids are compounds of the formula CnF(2n+1)CO2H that belong to ... 28 May 2020). "Ice Core Record of Persistent Short‐Chain Fluorinated Alkyl Acids: Evidence of the Impact From Global ...
... trifluoroperoxyacetic acid, TFPAA) is an organofluorine compound, the peroxy acid analog of trifluoroacetic acid, with the ... or by reacting iodobenzene with a combination of trifluoroperacetic acid and trifluoroacetic acid: Trifluoroperacetic acid is ... Hiyama, Tamejiro (2000). "8.2 Trifluoroacetic acid and Trifluoroperacetic acid". Organofluorine Compounds: Chemistry and ... can be used to form trifluoroperacetic acid for some reactions from trifluoroacetic acid. CF 3COOH + H 2O 2 → CF 3COOOH + H 2O ...
In the atmosphere, HFO-1234yf degrades to trifluoroacetic acid, which is a mildly phytotoxic strong organic acid with no known ... HFO-1234yf has been shown to atmospherically transform into the ultrashort PFAS trifluoroacetic acid (TFA) leading to potential ... 3-Tetrafluoropropene into Trifluoroacetic Acid from Its Application in Automobile Air Conditioners in China, the United States ... "Environmental risk assessment of trifluoroacetic acid". International Journal of Human and Ecological Risk Assessment. 5 (1): ...
Trichloroacetic acid Trifluoroacetic acid "Drinking Water". cehtp.org. Archived from the original on 2019-04-08. Retrieved 2016 ... Haloacetic acids are carboxylic acids in which a halogen atom takes the place of a hydrogen atom in acetic acid. Thus, in a ... ClCH2COOH dichloroacetic acid (DCA) Cl2CHCOOH trichloroacetic acid (TCA) Cl3CCOOH monobromoacetic acid (MBA) BrCH2COOH ... For example, chloroacetic acid would have the structural formula CH2ClCO2H. In the same manner, in dichloroacetic acid two ...
Acetyl chloride Trifluoroacetic acid Nagashima, H.; Isono, Y.; Iwamatsu, S. (2001). "Copper-Catalyzed Cyclization of N- ...
Oxidation of trifluoroethanol yields trifluoroacetic acid. It also serves as a source of the trifluoroethoxy group for various ... Trifluoroethanol is produced industrially by hydrogenation or the hydride reduction of derivatives of trifluoroacetic acid, ... It is classified as a hard Lewis acid and its acceptor properties are discussed in the ECW model yielding EA = 2.07 and CA = ... Zhong L, Johnson WC (May 1992). "Environment affects amino acid preference for secondary structure". Proceedings of the ...
... can also be used as direct C-H difluoromethylating reagent. Fluoroacetic acid Trifluoroacetic acid " ... Difluoroacetic acid is a chemical compound with formula CHF2COOH. It is a dihalogenocarboxylic acid, specifically a structural ... "Difluoroacetic acid". Sigma-Aldrich. Tung, Truong Thanh; Christensen, Søren Brøgger; Nielsen, John (2017). "Difluoroacetic Acid ... Fluorinated carboxylic acids, Difluoromethyl compounds, All stub articles, Organohalide stubs). ...
... is far less basic than pyridine, being unreactive with Lewis acids. Trifluoroacetic acid does not protonate the ...
A typical acid is trifluoroacetic acid (TFA). The reaction is stoichiometric. Hydrosilanes are used for the deoxygenation of ... In this type of reaction, carbocations are generated by the action of strong Lewis or Brønsted acids in the presence of ...
Strong acids such as hydrochloric acid or sulfuric acid can protonate the trifluoroacetate ion to trifluoroacetic acid: CF 3 CO ... With a pKa of 0.23 for trifluoroacetic acid, the trifluoroacetate ion is an extremely weak base compared to acetic acid, which ... Sodium fluoroacetate Trifluoroacetic acid Sodium acetate Chang, Ying; Cai, Chun (June 2005). "Trifluoromethylation of carbonyl ... One convenient method is by dissolving an equivalent amount of sodium carbonate in 50% aqueous solution of trifluoroacetic acid ...
Solvents include trifluoroacetic acid, methanol, dichloromethane, chloroform, and acetonitrile. Many derivatives of ... as a catalyst using acetic acid as a solvent. A side product is 2,6-bis-(hydroseleno)selenacyclohexane. When 5-chloro-2,4- ... pentadienenitrile derivatives react with sodium hydroselenide, or sodium selenite, and are then treated with perchloric acid, a ...
Trifluoroacetic acid is found to facilitate the overall reaction. Kirsch and co-workers were able to hydroxylate keto compounds ... Commercial IBX is stabilized by carboxylic acids such as benzoic acid and isophthalic acid. The reaction mechanism for an ... IBX is prepared from 2-iodobenzoic acid, potassium bromate, and sulfuric acid. Frigerio and co-workers have also demonstrated, ... elevated temperatures or trifluoroacetic acid solvent). The reaction mechanism for this glycol cleavage is based on initial ...
Trifluoroacetic acid, which is a common reagent in organic synthesis. Amounts of acetic acid used in these other applications ... It then can be titrated using a solution in glacial acetic acid of a very strong acid, such as perchloric acid. Acetic acid ... Acetic acid is the second simplest carboxylic acid (after formic acid). It is an important chemical reagent and industrial ... Halogenated acetic acids are produced from acetic acid. Some commercially significant derivatives: Chloroacetic acid ( ...
For these applications VOF3 is typically dissolved in trifluoroacetic acid. Vanadium(V) oxytrifluoride reacts with ...
Trifluoroacetic acid, a moderately strong acid useful in organic chemistry. Heptafluorobutyric acid, a moderately strong acid ... Triflic acid, a useful strong acid perfluorobutanesulfonic acid (PFBS) used as a replacement for PFOS in 3M's reformulated ... Pentafluorobenzoic acid, a moderately strong acid of interest in research community. Perfluorooctanoic acid (PFOA),a surfactant ... "FAQ". Perfluorooctanoic Acid (PFOA) and Fluorinated Telomers. Retrieved 11 May 2011. Auer, Charles, Frank Kover, James Aidala, ...
It degrades to Trifluoroacetic acid (TFA) via photolytic degradation in sunlight. Novec and TFA do not bioaccumulate. Fire ... "Hydrolysis and Atmospheric Oxidation Reactions of Perfluorinated Carboxylic Acid Precursors" (PDF). University of Toronto. ...
... that perfluorocarboxylic acid is trifluoroacetic acid. The two metabolites of topilutamide namely BP-34 and trifluoroacetic ... Perfluoroacylamido-arylpropanamides decompose hydrolytically to BP-34 and their corresponding perfluorocarboxylic acid. In the ... acid were undetectable in human serum (below the detection limit of 5 ng/mL) along with the parent compound topilutamide, in ...
Small amounts of trifluoroacetic acid can be formed from both halothane and isoflurane metabolism and possibly accounts for ... Ma TG, Ling YH, McClure GD, Tseng MT (October 1990). "Effects of trifluoroacetic acid, a halothane metabolite, on C6 glioma ... Hankins DC, Kharasch ED (1997-05-09). "Determination of the halothane metabolites trifluoroacetic acid and bromide in plasma ... and is thought to result from the metabolism of halothane to trifluoroacetic acid via oxidative reactions in the liver. About ...
Trifluoroacetic acid, often used in these reductions, is a strong, corrosive acid. Some hydrosilanes are pyrophoric. Larson, ... Brønsted acids may also be used. Tertiary alcohols undergo facile reduction using boron trifluoride etherate as the Lewis acid ... Acid-catalyzed Reactions of 2,4,6-Tri- t -butyl- and 2-Methyl-4,6-di-t-butylbenzyl Alcohols and Chlorides". Canadian Journal of ... In some cases, the transition metal simply serves as a Lewis acid that coordinates to the ketone oxygen; however, some metals ( ...
... can disrupt the Krebs cycle. In contrast with monofluoroacetic acid, difluoroacetic acid and trifluoroacetic ... Difluoroacetic acid Trifluoroacetic acid Wikimedia Commons has media related to Fluoroacetic acid. as anion of fluoroacetic ... Its pKa is 2.66, in contrast to 1.24 and 0.23 for the respective di- and trifluorinated acids. Fluoroacetic acid is used to ... Fluoroacetic acid is a organofluorine compound with formula CH2FCO2H. It is a colorless solid that is noted for its relatively ...
It is prepared by condensation of esters of trifluoroacetic acid with acetone. According to an analysis by proton NMR ...
Triflic acid (CF3SO3H) and trifluoroacetic acid (CF3CO2H) are useful throughout organic synthesis. Their strong acidity is ... The polymeric analogue of triflic acid, nafion is a solid acid that is used as the membrane in most low temperature fuel cells ... The fluorosurfactants perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) are two of the most studied because ... The triflate-group (the conjugate base of the triflic acid) is a good leaving group in substitution reactions. Of topical ...
Removal of the BOC group in amino acids can be accomplished with strong acids such as trifluoroacetic acid in dichloromethane, ... "Removal of t-Butyl and t-Butoxycarbonyl Protecting Groups with Trifluoroacetic acid". Int. J. Pept. Protein Res. 12 (5): 258- ... C Dissolving desired protected compound in a 50/50 mix of dichloromethane and trifluoroacetic acid "Rules for abbreviation of ... Amino Acids, Peptides and Proteins in Organic Chemistry. Vol. 4. Wiley-VCH. pp. XVIII-LXXXIV. doi:10.1002/9783527631827.ch1. ...
Trifluoroacetic acid (TFA) is added to catalyse the imine bond-forming reactions. The preparation of the tri-ring Borromeate ...
Removal of the Boc in amino acids can be accomplished with strong acids such as trifluoroacetic acid neat or in dichloromethane ... The Boc group can later be removed from the amine using moderately strong acids (e.g., trifluoroacetic acid). Thus, Boc serves ... The use of triethylsilane as a carbocation scavenger in the presence of trifluoroacetic acid in dichloromethane has been shown ... "Removal of t-Butyl and t-Butoxycarbonyl Protecting Groups with Trifluoroacetic acid". International Journal of Peptide and ...
With trifluoroacetic acid a similar compound solvated with trifluoroacetic acid is produced. It also reacts with acetic ... Tin(IV) nitrate is a salt of tin with nitric acid. It is a volatile white solid, subliming at 40 °C under a vacuum. Unlike ... Tin(IV) nitrate reacts with trifloroacetic acid anhydride to yield (NO2+)2[Sn(OOCCF3)62−] which is a nitronium salt. ... oxide and nitric acid resulted in a formation of tin(II) nitrate hydroxide. This compound is sensitive to water, it hydrolyzes ...
The Boc group is removed with acid, such as trifluoroacetic acid (TFA). This forms a positively charged amino group in the ... and adding an excess of each amino acid (between 2- and 10-fold). The minimization of amino acid racemization during coupling ... Each amino acid to be coupled to the peptide chain N-terminus must be protected on its N-terminus and side chain using ... First an amino acid is coupled to the resin. Subsequently, the amine is deprotected, and then coupled with the activated ...
Acids such as trifluoroacetic acid and formic acid may be used for cleavage. Like other biomolecules, proteins can also be ... Strong mineral acids can readily hydrolyse the peptide bonds in a protein (acid hydrolysis). The standard way to hydrolyze a ... C for around 24 hours in 6M hydrochloric acid. However, some proteins are resistant to acid hydrolysis. One well-known example ... The amino acids may then be reused for protein synthesis. The intracellular degradation of protein may be achieved in two ways ...
Trifluoroacetic acid is a corrosive acid but it does not pose the hazards associated with hydrofluoric acid because the carbon- ... TFA is a stronger acid than acetic acid, having an acid ionisation constant, Ka, that is approximately 34,000 times higher, as ... Fluoroacetic acid - highly toxic but naturally occurring rodenticide CH2FCOOH Difluoroacetic acid Trichloroacetic acid, the ... Trifluoroacetic acid (TFA) is an organofluorine compound with the chemical formula CF3CO2H. It is a structural analogue of ...
Trifluoroacetic acid eluent additive for LC-MS, LiChropur™, ≥99.0% (GC); CAS Number: 76-05-1; EC Number: 200-929-3; Synonyms: ... as an effective alternative to acid modifiers, formic acid (FA) and trifluoroacetic acid (TFA) in the LC-UV/MS analysis of ... Trifluoroacetic acid is commonly used as a mobile phase additive in liquid chromatography-mass spectrometry (LC-MS). Features: ... Trifluoroacetic acid may be used as a mobile phase additive for the analysis of basic compounds in biological samples using ...
Trifluoroacetic Acid, LC-MS Eluent at Thomas Scientific, your trusted partner in Science. ... Water, with 0.1% Trifluoroacetic Acid, LC-MS Eluent. * PRODUCT AVAILABILITY: Did you know you can view a products availability ...
Acetonitrile with trifluoroacetic acid (0.1%), HPLC Grade, Fisher Chemical at Fishersci.com ... Mobile phase for HPLC, Acetonitrile with trifluoroacetic acid (0.1%), HPLC Grade, Fisher Chemical ...
parameter for TFA (trifluoroacetic acid). From: liupeng012_at_mail.nankai.edu.cn. Date: Fri May 13 2011 - 03:36:55 CDT ... Is there anybody who has the parameters of CHARMM FF for trifluoroacetic acid (TFA)? Thanks. Liupeng 2011-05-13 liupeng012_at_ ...
GFS Chemicals is a leading supplier of Trifluoroacetic Acid, SKU 83252. GFS Chemicals has the expertise to handle your C2HF3O2 ...
Trifluoroacetic acid. Trifluoroacetic acid CAS No. : 76-05-1 MolFormula : C2HF3O2 MolWeight : 114.022 MDL No. : MFCD00004169 ...
Trifluoroacetic acid,Ethyl trifluoroacetate--Jinan WANXINGDA CHEMICAL Co.,Ltd. ...
Trifluoroacetic acid,Ethyl trifluoroacetate--Jinan WANXINGDA CHEMICAL Co.,Ltd. ...
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice ...
Trifluoroacetic acid Reagent Grade, 99% - We offer a range of laboratory equipment with no minimum orders and competitive ... Trifluoroacetic acid Reagent Grade, 99%. Trifluoroacetic acid Reagent Grade, 99% , Acids and Bases > Reagent Grade Acids , ... Trifluoroacetic acid Reagent Grade, 99% *More from - Acids and Bases > Reagent Grade Acids ...
Buy online Octreotide-phenylalanine-d8 di-Trifluoroacetic Acid Salt, 10mg O239952-10mg at best price in India on Biomall. ...
Deichmann WB, Gerarde HW [1969]. Trifluoroacetic acid (3FA). In: Toxicology of drugs and chemicals. New York, NY: Academic ...
Fluorochrome PLGA poly (lactide ethylene glycol) PLA polylactic acid PCL Polycaprolactone Phospholipid polyethylene glycol ... CAS#79886-55-8 4 - (4-maleimide phenyl) butyric acid-n-succinimide ester ... N-(2-Aminoethyl)maleimide Trifluoroacetic Acid. Chinese alias. N-(2-Aminoethyl)maleimide Trifluoroacetic Acid. ...
... ... In this paper, we have systematically studied the influence of trifluoroacetic acid, acetic acid and their salts on the ... In this paper, we have systematically studied the influence of trifluoroacetic acid, acetic acid and their salts on the ... which can be attributed to the influence of pH caused by the acid- or salt-form of additives. The pitch sizes of the helical ...
Accepted Manuscript: Calculation of the relative basicity of three α,ω‐diphenylpolyenes with trifluoroacetic acid ... Title: Calculation of the relative basicity of three α,ω‐diphenylpolyenes with trifluoroacetic acid ... diphenylpolyenes with trifluoroacetic acid". Journal of Physical Organic Chemistry (). Country unknown/Code not available. ... diphenylpolyenes with trifluoroacetic acid. Journal of Physical Organic Chemistry, (). Retrieved from https://par.nsf.gov/ ...
In the present study, we show that benzoic acid derivatives isolated from Bjerkandera adusta promote the activity of the two ... our results suggest that the hydroxybenzoic acid scaffold could be considered as a promising candidate for the development of ... 3-chloro-4-methoxybenzoic acid) showed the most potent interaction with both enzymes, which justifies the strong activation of ... trifluoroacetic acid. UPP. ubiquitin-proteasome pathway. References. *Nakanishi, H.; Tominaga, K.; Amano, T.; Hirotsu, I.; ...
Dive into the research topics of Simplified method for trace analysis of trifluoroacetic acid in plant, soil, and water ... title = "Simplified method for trace analysis of trifluoroacetic acid in plant, soil, and water samples using headspace gas ... T1 - Simplified method for trace analysis of trifluoroacetic acid in plant, soil, and water samples using headspace gas ... N2 - A simple and sensitive analytical procedure was developed to determine the concentration of trifluoroacetic acid (TFA) in ...
Trifluoroacetic acid is (1) produced naturally and synthetically, (2) used in the chemical industry, and (3) a potential ... Trifluoroacetic acid (TFA) is a breakdown product of several hydrochlorofluorocarbons (HCFC), regulated under the Montreal ... Sources, fates, toxicity, and risks of trifluoroacetic acid and its salts: Relevance to substances regulated under the Montreal ... Sources, fates, toxicity, and risks of trifluoroacetic acid and its salts: Relevance to substances regulated under the Montreal ...
Hexafluorophosphoric Acid. *Potassium Hexafluorophosp. *Ammonium Hexafluorophosph. *Trifluoroacetic acid. API. *Glimepiride. * ...
Heptafluorobutyric acid; find Sigma-Aldrich-843443 MSDS, related peer-reviewed papers, technical documents, similar products & ... Heptafluorobutyric acid for synthesis; CAS Number: 375-22-4; Synonyms: ...
4-Methylphenyl ester of trifluoroacetic acid; p-Cresol, trifluoroacetate; Trifluoroacetic acid, 4-tolyl ester ... Acetic acid, trifluoro-, 4-methylphenyl ester. *Formula: C9H7F3O2 ... Other names: Acetic acid, trifluoro-, p-tolyl ester; p-Tolyl ...
The counter ion was a trifluoroacetic acid (TFA). This PLL had a degree of polymerization that ranged between 80 and 120 amino ... However, due to the complexity of samples, extracting and purifying nucleic acid is often the limiting factor in these methods ... Nanayakkara, I.A.; Cao, W.; White, I.M. Simplifying Nucleic Acid Amplification from Whole Blood with Direct Polymerase Chain ... Cadiere A., Faye C., Francois C., Garrelly L.: Method for purifying and concentrating nucleic acids. WO 2017005754 A1. ...
After digestion, the reaction was terminated by the addition of trifluoroacetic acid. Desalting was performed by solid-phase ... The reaction was quenched with 0.4% formic acid, and peptides were desalted with C18 stage tips64, dried in a vacuum ... Peptides were subsequently separated in a 2-90% acetonitrile gradient in 0.1% formic acid using a PicoFrit analytical column ( ... formic acid. SIL peptides and iRT (Pierce) retention time standards (used here as a quality control for retention time shift) ...
Trifluoro acetic acid. 76-05-1. Liquid. ,480. Trifluoro methansulfonic acid. 1493-13-6. Liquid. ,480. ... Serged and bound seams are degraded by some hazardous liquid chemicals, such as strong acids, and should not be worn when these ...
For example, acetic acid has a specific gravity (sg) of 1.0491 while acetone has a sg of 0.785 (784.58 kg/cu.m) - see table ...
Regioselective ortho amination of an aromatic C-H bond by trifluoroacetic acid via electrochemistry. Org. Lett. 21, 5581-5585 ( ... Electrosynthesis of 15N-labeled amino acids from 15N-nitrite and ketonic acids *Yongmeng Wu ... Wang, Z., He, Z., Zhang, L. & Huang, Y. Iridium-catalyzed aerobic α,β-dehydrogenation of γ,δ-unsaturated amides and acids: ... GF, graphite felt; mCPBA; LDA, lithium diisopropylamide; 3-chloroperoxybenzoic acid, PMP, 4-MeOPh. ...
2: trifluoroacetic acid / dichloromethane / 0 °C. With trifluoroacetic acid; In tetrahydrofuran; dichloromethane; ... 3-(3-oxo-2,3-dihydro-4H-benzo[b][1,4]oxazin-4-yl)propanoic acid ...
  • TFA is prepared industrially by the electrofluorination of acetyl chloride or acetic anhydride, followed by hydrolysis of the resulting trifluoroacetyl fluoride: CH 3COCl + 4 HF → CF 3COF + 3 H 2 + HCl CF 3COF + H 2O → CF 3COOH + HF Where desired, this compound may be dried by addition of trifluoroacetic anhydride. (wikipedia.org)
  • TFA is the precursor to many other fluorinated compounds such as trifluoroacetic anhydride, trifluoroperacetic acid, and 2,2,2-trifluoroethanol. (wikipedia.org)
  • It is a structural analogue of acetic acid with all three of the acetyl group's hydrogen atoms replaced by fluorine atoms and is a colorless liquid with a vinegar-like odor. (wikipedia.org)
  • TFA is a stronger acid than acetic acid, having an acid ionisation constant, Ka, that is approximately 34,000 times higher, as the highly electronegative fluorine atoms and consequent electron-withdrawing nature of the trifluoromethyl group weakens the oxygen-hydrogen bond (allowing for greater acidity) and stabilises the anionic conjugate base. (wikipedia.org)
  • In this paper, we have systematically studied the influence of trifluoroacetic acid, acetic acid and their salts on the synthesis of helical mesoporous materials in the presence of a cationic surfactant cetyltrimethylammonium bromide (CTAB) as a template. (edu.au)
  • For example, acetic acid has a specific gravity (sg) of 1.0491 while acetone has a sg of 0.785 ( 784.58 kg/cu.m) - see table below. (simetric.co.uk)
  • Testing also detected trifluoroacetic acid (TFA) and trifluoromethanesulfonic acid (TFMS). (healthday.com)
  • Trifluoroacetic or trifluoromethanesulfonic acids may also be adequate substitutes. (ilpi.com)
  • The methods used were Driselase digestion and trifluoroacetic acid (TFA) hydrolysis. (bl.uk)
  • This can be achieved by acid hydrolysis, typically using hydrochloric acid (HCl) or trifluoroacetic acid (TFA). (pharmiweb.com)
  • The hydrolysis process breaks the peptide bonds, converting proteins into their constituent amino acids. (pharmiweb.com)
  • HPLC can detect and quantify amino acids in trace amounts. (pharmiweb.com)
  • IEC, HPLC or CE) and detection methods described above to identify and quantify amino acids in protein samples. (pharmiweb.com)
  • Combining mass spectrometry with separation techniques such as HPLC or CE can improve the accuracy and sensitivity of amino acid analysis. (pharmiweb.com)
  • SDR enzymes have critical roles in lipid, amino acid, carbohydrate, cofactor, hormone and xenobiotic metabolism as well as in redox sensor mechanisms. (researchgate.net)
  • Protein amino acid analysis is a technique for determining the type and amounts of amino acids in a protein sample, providing information on protein composition, post-translational modifications and overall protein quality. (pharmiweb.com)
  • By gaining insight into amino acid content, researchers can assess protein purity, determine changes in amino acid composition, and evaluate protein stability. (pharmiweb.com)
  • What is Protein Amino Acid Analysis? (pharmiweb.com)
  • Automated instruments specifically designed for protein amino acid analysis. (pharmiweb.com)
  • A reversed-phase column is commonly used for amino acid analysis. (pharmiweb.com)
  • The 131 I radiolabel generally clears rapidly from the tumor after internalization and subsequent degradation of the bivalent l -amino acid peptide ( l -a.a. peptide) in the tumor cells. (snmjournals.org)
  • We have developed an effective pretargeting system based on a biologically produced bs-mAb (antirenal cell carcinoma [RCC] x anti-DTPA(In) bs-mAb: G250xDTIn-1) and an 111 In-labeled bivalent l -amino acid peptide ( l -a.a. peptide) (Ac-Phe-Lys(DTPA)-Tyr-Lys(DTPA)-NH 2 ) (DTPA is diethylenetriaminepentaacetic acid) ( 10 ). (snmjournals.org)
  • The analysis involves extraction of TFA by sulfuric acid and methanol followed by derivatization to the methyl ester of TFA (MTFA). (elsevierpure.com)
  • Trifluoroacetic acid is commonly used as a mobile phase additive in liquid chromatography-mass spectrometry (LC-MS). (sigmaaldrich.com)
  • Trifluoroacetic acid may be used as a mobile phase additive for the analysis of basic compounds in biological samples using hydrophilic interaction liquid chromatography-electrospray ionization coupled to tandem mass spectrometry (HILIC-ESI/MS/MS) and reversed-phase liquid chromatography coupled to tandem mass spectrometry (RP-LC-MS/MS). (sigmaaldrich.com)
  • A simple and sensitive analytical procedure was developed to determine the concentration of trifluoroacetic acid (TFA) in plant, soil, and water samples. (elsevierpure.com)
  • The amino acids are eluted in a specific order and their concentration can be determined by various detection methods. (pharmiweb.com)
  • Can detect specific amino acids based on unique absorbance spectra, thus providing valuable information about the concentration of amino acids in protein samples. (pharmiweb.com)
  • Fluoroacetic acid - highly toxic but naturally occurring rodenticide CH2FCOOH Difluoroacetic acid Trichloroacetic acid, the chlorinated analog Kreglewski, A. (1962). (wikipedia.org)
  • Amino acids are first converted into volatile derivatives, which are then separated and detected by gas chromatography. (pharmiweb.com)
  • After derivatization, the amino acids are separated using liquid chromatography. (pharmiweb.com)
  • One complication to its use is that TFA forms an azeotrope with water (b. p. 105 °C). TFA is popularly used as a strong acid to remove protecting groups such as Fmoc and BOC used in organic chemistry and peptide synthesis. (wikipedia.org)
  • a ) Maximal fluorescence response to 10 μM glucagon-like peptide-1 (GLP-1) of the prototype GLP-1 sensor and the N-terminus deletion variants (16 or 23 first amino acids). (elifesciences.org)
  • To improve the residence time of the iodine label in the tumor, a new bivalent peptide was synthesized that is peptidase resistant and consists of 4 d -amino acids ( d -a.a. peptide). (snmjournals.org)
  • Following UV examination, the compounds were visualized by treatment with trifluoroacetic-acid or 25 percent sulfuric-acid. (cdc.gov)
  • Trifluoroacetic-acid treatment did not reveal the presence of blue compounds with Rf values resembling any of the standards. (cdc.gov)
  • The most commonly found PFAS was perfluorooctanoic acid (PFOA), which has been banned worldwide since 2020. (healthday.com)
  • Results show that helical mesostructures can be successfully synthesized when CF3COO- anions were used as additives with an additive/CATB molar ratio (R) range of 0.1-0.375 for the CF3COOH/CTAB templating system and a relatively wider R range of 0.1-0.5 for the CF3COONa/CTAB templating system, which can be attributed to the influence of pH caused by the acid- or salt-form of additives. (edu.au)
  • As an acid or as a salt TFA is low to moderately toxic to a range of organisms. (edu.au)
  • It is a reagent used in organic synthesis because of a combination of convenient properties: volatility, solubility in organic solvents, and its strength as an acid. (wikipedia.org)
  • Polyphenols found in the enzyme preparation were found to interfere with the reduction of the dinitrosalicylic acid reagent. (who.int)
  • The modular synthesis is based on Suzuki cross-coupling of the aryl substituents as boronic acid precursors with 5,8-dibromo-2-( tert -butyl)-4,9-dimethoxy-2,3-dihydro-1H-phenalen-1-one, and the subsequent transformation of the product to the desired 2,5-diaryl 6-hydroxyphenalenone in a reduction/deprotection sequence. (thieme-connect.com)
  • In the present study, we show that benzoic acid derivatives isolated from Bjerkandera adusta promote the activity of the two main protein degradation systems, namely the ubiquitin-proteasome (UPP) and especially the autophagy-lysosome pathway (ALP) in human foreskin fibroblasts. (mdpi.com)
  • In the cell, RNF213 was shown to be involved in fatty acid metabolism ( 11 ), and to associate with intracellular lipid droplets in a manner dependent on its E3 ligase and ATPase activities ( 12 ). (biorxiv.org)
  • 1995). Diisocyanates and acid anhydrides cyanates has a low association with atopy, low prevalence are among the most common low molecular weight (LMW) with specific IgE antibodies and a mixed Th1-Th2 response classes of chemicals responsible for occupational asthma. (cdc.gov)
  • Trifluoroacetic acid (TFA) is an organofluorine compound with the chemical formula CF3CO2H. (wikipedia.org)
  • The mobile phase, typically a gradient of water and organic solvent, facilitates the elution of amino acids from the column. (pharmiweb.com)
  • IEC separates amino acids based on their charge characteristics using ion exchange resins. (pharmiweb.com)
  • TFA is also less oxidizing than sulfuric acid but more readily available in anhydrous form than many other acids. (wikipedia.org)
  • Trifluoroacetic acid (TFA) is a breakdown product of several hydrochlorofluorocarbons (HCFC), regulated under the Montreal Protocol (MP), and hydrofluorocarbons (HFC) used mainly as refrigerants. (edu.au)
  • Amino acids are generally not very amenable to direct detection by LC-MS due to their low ionization efficiency. (pharmiweb.com)
  • The column separates the amino acids based on their hydrophobicity, allowing for their individual detection and quantification. (pharmiweb.com)
  • Once separated by LC, the amino acids enter the mass spectrometer for detection and quantification. (pharmiweb.com)
  • I was wondering if anyone knows of any actual data about the stability of various perchloric acid-organic solvent mixtures. (ilpi.com)
  • I've had some problems in the past with other witch's brews used for electropolishing, after which I determined that the literature-reported composition was beyond the actual stability limit for the particular (ethanol-nitric acid) system, so that's kind of sensitized me to this application. (ilpi.com)
  • The investigator tells me that it's the acid strength that's really needed, not the oxidizing power. (ilpi.com)
  • shatavari d1-trifluoroacetic acid is very confusing negramm and depends on the size of fines. (eventenergy.ru)
  • The effect of bs-mAb-diDTPA-bs-mAb (DTPA is diethylenetriaminepentaacetic acid) bridging at the tumor cell surface on the internalization of the bs-mAb-diDTPA complex was investigated in SK-RC-52 tumor-bearing mice. (snmjournals.org)
  • 7.5%) of the approximately 0.2 µg acid equivalents/L estimated to be present at the start of the millennium. (edu.au)