• In this guide, we outline the mechanism of RP-HPLC protein analysis and highlight all 20 amino acids in chromatography. (ftloscience.com)
  • RP-HPLC separates proteins based on hydrophobic bonding between the column's stationary phase (hydrocarbon bonded-silica) and the protein's hydrophobic amino acid residues (leucine, phenylalanine, valine, isoleucine, etc. (ftloscience.com)
  • By separating proteins based on the hydrophobic amino acid residues instead of shape or size, RP-HPLC can differentiate between proteins that have nearly identical structures! (ftloscience.com)
  • We present a new chromatographic method for the HPLC separation of underivatized amino acids using an acidic, aqueous mobile phase in conjunction with a mixed-mode stationary phase that can be interfaced with the LC IsoLink for compound-specific delta13C analysis. (ox.ac.uk)
  • 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)
  • The new flexible automatic Amino Acid Analyzer L-8900 combines the advantages of the classical ion exchange separation method with the modern HPLC techniques. (labmate-online.com)
  • This graph shows the relative retention of acids, neutrals, and bases for different Thermo Scientific HILIC (U)HPLC columns. (thermofisher.com)
  • This study aimed to assess the clinical significance of amino acid profile assay in autism using cation-exchange chromatography with ninhydrin postcolumn derivatization. (tubitak.gov.tr)
  • All participants were subjected to the assay of plasma amino acids (essential, nonessential, and nonstandard) using cation-exchange chromatography with postcolumn derivatization by ninhydrin. (tubitak.gov.tr)
  • Therefore, after these typical treatments to obtain collagen hydrolysate, peptides with varying lengths and varying C- and N-terminal amino acids are formed. (springer.com)
  • Finally, at the brush border, peptidases are present that cleave peptides down to small peptides and amino acids, ready for uptake into enterocytes and transport to the blood. (springer.com)
  • Results of this study suggest that reverse phase LC with pre-column OPTA derivatization can be applied to accurately measure primary amino acids in individual feedstuffs. (psu.edu)
  • After derivatization, the amino acids are separated using liquid chromatography. (pharmiweb.com)
  • The first technique (ion-exchange chromatography with postcolumn derivatization) allows many components to be analyzed at once but the method run times are long. (shimadzu.com)
  • Moreover, we analyzed changes in transcriptomics using RNA sequencing and metabolomics using gas chromatography-tandem mass spectrometry (GC-MS/MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) in PM 2.5 -treated HL-1 cells. (nih.gov)
  • Corn, soybean meal, and isolated soybean protein samples were acid-hydrolyzed for amino acid content by reverse phase liquid chromatography (LC) and by conventional ion-exchange chromatography (IEC) using an amino acid analyzer. (psu.edu)
  • Elkin, RG 1984, ' Quantitative amino acid analysis of feedstuff hydrolysates by reverse phase liquid chromatography and conventional ion-exchange chromatography ', Journal of the Association of Official Analytical Chemists , vol. 67, no. 5, pp. 1024-1026. (psu.edu)
  • Analysis of amino acid 13C abundance from human and faunal bone collagen using liquid chromatography/isotope ratio mass spectrometry. (ox.ac.uk)
  • Metabolite characterization was conducted with matrix assisted laser desorption ionization (MALDI) and liquid chromatography mass spectrometry (LC-MS). The metabolomics analysis revealed a significant increase in 44 metabolites in BALF, including 1,2-Dipalmitoyl-sn-glycero-3-phosphoglycerol (DPPG) and cholesterol in the rats exposed to 112 microg at the 7- and 28-day time points. (cdc.gov)
  • Such mixed solutions are also useful in separation science, as extraction solvents and in liquid chromatography. (scirp.org)
  • The specific microfluidic flow, TRDF, was applied to capillary liquid chromatography [8] and micro-extraction [9]. (scirp.org)
  • Hydrophilic interaction chromatography (HILIC) is a liquid chromatography technique that is used to separate moderate to highly hydrophilic and polar compounds based on their retention on a hydrophilic stationary phase versus the hydrophilic aqueous polar organic mobile phase. (news-medical.net)
  • In traditional Reverse-phase Liquid Chromatography (RPLC), polar, hydrophilic and charged compounds are preferentially retained on the column. (news-medical.net)
  • In GC, the mobile phase is an inert gas, usually helium or nitrogen, and the stationary phase is either a solid adsorbent, termed gas-solid chromatography (GSC), or a liquid adsorbed onto an inert support, termed gas-liquid chromatography (GLC, or just GC). (sigmaaldrich.com)
  • More complex meteoritic amino acids are thought to require aqueous processing and are thus thought to form on planetesimals while they are hot enough to sustain liquid water 14 . (nature.com)
  • The analysis of protein hydrolysates using ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) can be complex. (springer.com)
  • Silica gel is the most widely used base material in liquid chromatography, although the interactions of biomolecules at the aqueous interface are not fully understood. (tum.de)
  • Enzyme-assisted physicochemical enantioseparation processes - Part II: Solid-liquid equilibria, preferential crystallization, chromatography and racemization reaction. (mpg.de)
  • In total, 791 annotated endogenous metabolites were measured by ultra-performance liquid chromatography-tandem mass spectrometry. (lu.se)
  • Sitka spruce) was partially purified by a combination of lectin affinity and immobilized metal ion affinity chromatography. (who.int)
  • A computer exercise in bioinformatics and a laboratory task for several days that includes experimental design and common biochemical methods including protein purification, affinity chromatography, electrophoresis and activity analysis with fluorometrics. (lu.se)
  • Phenylketonuria (PKU), less commonly known as phenylalanine hydroxylase deficiency, is the most common inborn error of amino acid metabolism. (medscape.com)
  • The instructions for building nearly all the enzymes involved in metabolism are stored as deoxyribonucleic acid (DNA) in the nucleus of the cell. (newworldencyclopedia.org)
  • Pathway enrichment analysis highlighted branch-chained and aromatic amino acid synthesis/metabolism, aminoacyl-tRNA biosynthesis, and sphingolipid metabolism. (lu.se)
  • Conclusion: Our data suggest a graded derangement of the circulating metabolite profile from lean to obese to MetS, in particular for metabolites involved in amino acid synthesis/metabolism and sphingolipid metabolism. (lu.se)
  • Phenylketonuria (PKU) Phenylketonuria is a disorder of amino acid metabolism that causes a clinical syndrome of intellectual disability with cognitive and behavioral abnormalities caused by elevated serum phenylalanine. (msdmanuals.com)
  • Methylmalonic acidemia is an autosomal recessive disorder of amino acid metabolism, involving a defect in the conversion of methylmalonyl-coenzyme A (CoA) to succinyl-CoA. (medscape.com)
  • In organic acid fermentation, DuPont's acrylic chromatography resins can separate the organic acids from contaminating salts and residual dextrose with sharp and efficient elution peaks. (dupont.com)
  • The di- and tri- carboxylic acids will be more strongly retained and will have a longer elution time than the mono-carboxylic acids. (dupont.com)
  • The mobile phase, typically a gradient of water and organic solvent, facilitates the elution of amino acids from the column. (pharmiweb.com)
  • Furthermore, gel column chromatography on Sephadex G-150 indicated that the elution curves of the carbohydrate and protein overlapped significantly in sample P ( Figure 1 ). (scirp.org)
  • We wish to report that the application of column chromatography, using an ion-exchange resin ('Dowex-50', 250/500 mesh), led to the clean-cut and quantitative separation of dl-threonine and dlallothreonine. (erowid.org)
  • DuPont's resins offer cost-effective deashing and chromatographic purification of organic and amino acids while resisting osmotic stress. (dupont.com)
  • In organic and amino acid purification, DuPont provides styrenic and acrylic chromatographic separation media. (dupont.com)
  • Chromatographic enantioseparation of amino acids using a new chiral stationary phase based on a macrocyclic glycopeptide antibiotic. (mpg.de)
  • Compared with intact protein, the ingestion of protein hydrolysate accelerates protein digestion and absorption in the gut, increases amino acid availability after passage through the stomach, and tends to increase the incorporation rate of dietary amino acids into skeletal muscle protein [ 2 ]. (springer.com)
  • The goal of this research was to study if ascorbic acid applications could improve physiological mechanisms associated with water stress tolerance in young fruit trees. (frontiersin.org)
  • Upon rewatering, CO 2 assimilation and stomatal conductance of water-stressed 'Scarletprince' trees sprayed with ascorbic acid (one or two applications) were similar to those of well-irrigated trees, but water-stressed trees that had not received ascorbic acid did not recover photosynthetical functions. (frontiersin.org)
  • On the other hand, water-stressed 'CaroTiger' trees needed two applications of ascorbic acid to reach values of CO 2 assimilation similar to control trees but these applications did not improve their water status. (frontiersin.org)
  • In general terms, different response mechanisms to cope with water stress in presence of ascorbic acid were found in each cultivar, with 'Scarletprince' trees preferentially using proline as compatible solute and 'CaroTiger' trees relying on stomatal regulation. (frontiersin.org)
  • The application of ascorbic acid reduced cell membrane damage and increased catalase activity in water-stressed trees of both cultivars. (frontiersin.org)
  • These results suggest that foliar applications of ascorbic acid could be used as a management practice for improving water stress tolerance of young trees under suboptimal water regimes. (frontiersin.org)
  • Once the protein is denatured, it needs to be hydrolyzed to release individual amino acids. (pharmiweb.com)
  • The end product of protein digestion is a complex mixture of primarily dipeptides and tripeptides, along with individual amino acids [ 14 ]. (springer.com)
  • They were composed of glucose and mannose and 10 different amino acids and with molecular weights of 18,000 and 8000 Da, respectively. (scirp.org)
  • The amino acids are eluted in a specific order and their concentration can be determined by various detection methods. (pharmiweb.com)
  • 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)
  • Our GC solvents have been specially developed and tested for ECD, FID and MS detection or for headspace gas chromatography to ensure accurate, reliable and reproducible analytical results. (sigmaaldrich.com)
  • The concentrations show that N,N-dimethylglycine (DMG) is the most abundant amino acid in the TD1 particle, but below detection limit in the other. (nature.com)
  • Conclusion: The study revealed that autistic children exhibit distinct alterations in the plasma levels of some amino acids, which can in turn participate in the disease etiology and can be applied as a diagnostic tool for early detection of autism. (tubitak.gov.tr)
  • This can be achieved by acid hydrolysis, typically using hydrochloric acid (HCl) or trifluoroacetic acid (TFA). (pharmiweb.com)
  • 4. The results suggest that the pattern of nitrogen and amino acid absorption from partial enzymic hydrolysates of whole protein is markedly influenced by peptide chain length and that brush border peptide hydrolysis has an important rate limiting effect on absorption rates. (portlandpress.com)
  • N -acetylation fol owed by N -hydroxyl- lysed hydrolysis to release the was a C8-substituted deoxyguano- ation of the remaining amino function N -hydroxyarylamines, which can sine adduct. (who.int)
  • In general, amino acid values obtained by LC and IEC compared closely within and across feedstuffs, and both agreed well with published amino acid composition data. (psu.edu)
  • 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)
  • The composition of umami components detected in mushrooms consisted of 5′-nucleotides groups, namely, inosinic acid (IMP), adenylate monophosphate (AMP), guanylate monophosphate (GMP), xanthosine monophosphate (XMP), and free amino acid groups, namely: aspartic and glutamic acid. (hindawi.com)
  • This article for the first time presents the results of the study of qualitative and quantitative elemental and amino acid composition of the aboveground part of the plant Nepeta olgae Regel (L.) taken in the territory of Chust and Kosonsai districts (from the slopes of Gova and Kosonsai mountains) of Namangan region during the period before and during flowering (May-June, 2021-2022). (who.int)
  • Furthermore, the relationships between the amino acids and the geochemistry suggest that DMG formed on the Ryugu progenitor body during aqueous alteration. (nature.com)
  • The findings highlight the importance of aqueous chemistry for defining the ultimate concentrations of amino acids in primitive extraterrestrial samples. (nature.com)
  • I-LBP, ileal lipid-binding to the aqueous solubility of the fatty acid. (lu.se)
  • Quantitation of hemoglobin adducts of EO is performed using octapeptides with the same amino acid sequence as the N-terminal of the beta-chain of hemoglobin with EO attached at the valine residue. (cdc.gov)
  • The smaller polypeptide of M(r) ~73 kDa yielded an N-terminal amino-acid sequence that was homologous to laccase-like polyphenol oxidases (E.C. 1.10.3.2) from loblolly pine (Pinus taeda L.), poplar (Populus euramericana (Dode) Guinier) and Arabidopsis. (who.int)
  • The larger polypeptide (M(r) ~77 kDa) yielded an N-terminal amino-acid sequence that was homologous with a range of plant subtilisin-like serine proteinases. (who.int)
  • DuPont offers a full selection of high-quality strong acid cation and weak base anion ion exchange resins to tackle the challenging processing conditions that come with synthesizing organic and amino acids. (dupont.com)
  • These acids create significant osmotic stress during processing, making the resins physical stability a top requirement during purification. (dupont.com)
  • Producing high quality acids with highly stable ion exchange resins. (dupont.com)
  • The dissolved citric and lactic acids are subsequently purified through a deashing step using ion exchange resins. (dupont.com)
  • The high acid loading causes excessive osmotic stress, which can break ion exchange resins. (dupont.com)
  • DuPont is an industry leading ion exchange resin manufacturer, delivering resins with physical stability and purification performance for your acid production needs. (dupont.com)
  • DuPont offers a wide variety of ion exchange resins for the recovery and purification of essential amino acids, including lysine, histidine, tryptophan, methionine and glutamine. (dupont.com)
  • DuPont chromatography resins quickly and efficiently elute the salts and non-anion compounds while retaining the anionic compounds. (dupont.com)
  • IEC separates amino acids based on their charge characteristics using ion exchange resins. (pharmiweb.com)
  • To be used as raw materials in industrial chemicals and food additives, organic and amino acids require extra purification steps to meet the required product standards. (dupont.com)
  • This yields calcium citrate and calcium lactate solids that can be mixed with sulfuric acid resulting in partial purification of the organic acid as well as calcium sulfate byproducts. (dupont.com)
  • This enables isotopic measurement of non-volatile compounds previously not amenable to compound-specific analysis or requiring substantial modification for gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS), which results in reduced precision. (ox.ac.uk)
  • What is Protein Amino Acid Analysis? (pharmiweb.com)
  • Gas chromatography is suitable for the analysis of complex protein samples. (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)
  • This article will discuss the analysis of free fatty acid. (sigmaaldrich.com)
  • The complete AAA-solution from VWR offers sophisticated instrumentation, a wide variety of prepacked columns, an excellently developed gradient method combined with optimised ready-to-use buffers, creating the right answer for any analytical lab who is dealing with amino acid analysis. (labmate-online.com)
  • Two major problems exist with traditional amino acid analysis techniques. (shimadzu.com)
  • Jointly developed by Shimadzu and Ajinomoto Co., Inc., it features a special-purpose, fast analysis column and a LCMS-2020 mass spectrometer, which supports ultra-fast analysis speeds, to achieve the simultaneous analysis of 38 amino acid and amino acid-related components* in just nine minutes. (shimadzu.com)
  • UF-Amino Station is an excellent tool for the analysis of food products, such as meat and fermented foods containing many impurity components, and for the biochemical analysis of culture fluid. (shimadzu.com)
  • Permits the analysis of 38 amino acid-related components, such as anserine, citrulline, taurine, and GABA (γ-aminobutyric acid), in addition to the 20 major amino acid components. (shimadzu.com)
  • Gas chromatography (GC) is a common analytical technique used to separate and analyze volatile and semi-volatile compounds in a mixture. (sigmaaldrich.com)
  • Mutations can also cause such amino acid substitutions. (ftloscience.com)
  • This resistance to quinolones was caused by amino acid substitutions in the quinolone resistance-determining region (QRDR) of the DNA gyrase subunit gyrA , a key target of quinolones. (cdc.gov)
  • in December 2006, UniMod lists 495 modifications including 144 amino acid substitutions [6]. (lu.se)
  • For example, insulin -a protein that regulates blood sugar levels-comprises 51 amino acid residues. (ftloscience.com)
  • Several acidic and basic amino acid residues are charged when dissolved in water. (ftloscience.com)
  • 3. Absorption of total nitrogen and of 14 amino acid residues occurred to a significantly greater extent from the low molecular weight LH1 than from the higher molecular weight LH2. (portlandpress.com)
  • Surprisingly, only residues 2-32 of the 68 amino acid inhibitor are observed in the x-ray structure that forms an amphipathic helix. (usda.gov)
  • Amino acids are first converted into volatile derivatives, which are then separated and detected by gas chromatography. (pharmiweb.com)
  • The metabolites of note included small fatty acids such as decanoic and octanoic acid, amino acids such as serine and 1H-indole-3-acetic acid, and sugar derivatives such as glycerol. (medscape.com)
  • To a lesser extent, odd-chain fatty acid and cholesterol degradation also contribute. (medscape.com)
  • Goethe-Universita¨t, DE-60439 tein (I-LBP) and intestinal fatty acid-binding protein (I-FABP). (lu.se)
  • I-FABP) and bovine heart fatty acid-binding pro- tissues and in intracellular as well as extracellular tein (H-FABP). (lu.se)
  • ABSTRACT The national neonatal screening programme in the United Arab Emirates currently includes 16 disorders: congenital hypothyroidism, sickle-cell diseases, congenital adrenal hyperplasia, biotinidase deficiency and 12 amino acid, organic acid and fatty acid disorders. (who.int)
  • The incidence of screened disorders were 1:1 873 for congenital hypothyroidism, 1:14 544 for phenylketonuria, 1:3 526 for amino acid, organic acid and fatty acid disorders, 1:9 030 for classical congenital adrenal hyperplasia, 1:8 300 for biotinidase deficiency, 1:2 384 for sickle-cell disease and 1:121 for sickle-cell traits. (who.int)
  • An amino acid molecule contains at least one carboxylic acid group ( -COOH ) and at least one amine group ( -NH 2 ). (docbrown.info)
  • The primary suffix name for an aliphatic carboxylic acid is based on the ' longest carbon chain name *' for the - COOH bond system e.g. ethanoic acid, propanoic acid etc. (docbrown.info)
  • This is the 2nd carbon atom in the chain next to the carboxylic acid group. (docbrown.info)
  • However, the organic acids and sterols in the mycelium of the fungus are very low in quantity and are water-insoluble. (scirp.org)
  • All together, the active components in "An Luotong" are unlikely to be organic acids and sterols, thus remain to be elucidated. (scirp.org)
  • Enzyme-assisted physicochemical enantioseparation processes - part I: Production and characterization of a recombinant amino acid racemase. (mpg.de)
  • Structures of IARC Group 1 aromatic amines, drugs that are urothelial cancer in humans ( IARC, metabolized to Group 1 aromatic amines, and aristolochic acids. (who.int)
  • For example, lactic acid is used to make polylactic acid for the rapidly growing biodegradable plastics market. (dupont.com)
  • For example, one of the acid-refining techniques used for citric and lactic acids is lime precipitation. (dupont.com)
  • The process of making mandai cempedak by induction of lactic acid bacteria starter has received a patent number S00201708792. (hindawi.com)
  • The taste of mandai cempedak as a plant-derived product fermented by lactic acid bacteria is preferred [ 1 ], similar to other fermented products [ 3 ]. (hindawi.com)
  • Lactic acid bacteria as flavor enhancers and seasoning food products have been widely used [ 4 - 6 ]. (hindawi.com)
  • At this time, lactic acid fermentation takes place, subsequently providing bee bread rich in enzymatically-activated components[ 1 , 2 ]. (ijpsonline.com)
  • Amino acids are an example of such compounds. (ox.ac.uk)
  • Ionic and ionizable compounds typically rely on separation by ion exchange chromatography (IC) or ion pairing reversed-phase chromatography (IP-RPLC). (news-medical.net)
  • This study aims to observe panelist acceptance, proximate characteristics of amino acid, volatile compounds, and color profiles on five mixed formulas of fermented cempedak ( Artocarpus champeden ) and oyster mushroom ( Pleurotus ostreatus ) seasoning. (hindawi.com)
  • In conclusion, mandai cempedak powder to be mixed with other abundant raw materials such as oyster mushroom ( Pleurotus ostreatus ) can be used as a typical Indonesian flavor ingredient with unique characteristics in terms of its amino acid content, volatile compounds, and essential oils. (hindawi.com)
  • 1. A double lumen jejunal perfusion technique has been used in man to study the effect of peptide chain length on absorption of amino acid nitrogen from two partial enzymic hydrolysates of lactalbumin. (portlandpress.com)
  • The chemiluminescence of three α -amino acids with fluorescence properties was enhanced with the ternary solution. (scirp.org)
  • CE separates amino acids based on their electrophoretic mobility in a capillary filled with a buffer solution. (pharmiweb.com)
  • Using two-dimensional gas chromatography coupled to time-of-flight mass spectrometry, they measured a total 851 metabolites, 43 of which differed significantly in expression patterns between TBI cases and controls. (medscape.com)
  • Decanoic acid and some of these other metabolites that they're looking at are not traditional biomarkers," said Donald Marion, MD, MSc, senior consultant with the Defense and Veterans Brain Injury Center in Silver Spring, Maryland. (medscape.com)
  • Finally, the autistic group demonstrated significantly lower levels of α-aminoadipic acid, carnosine, and β-alanine and significantly higher levels of hydroxyproline, phosphoserine, β-amino-isobutyric acid, and ammonia as compared to controls. (tubitak.gov.tr)
  • Chemiluminescence in the presence of twenty types of α -amino acid was similarly examined by using the ternary organic solvent-rich solution. (scirp.org)
  • Even small volumes of alcohols such as Methanol used during sample preparation or in the injection solvent can affect the chromatography. (thermofisher.com)
  • Results: The levels of most of the essential amino acids were significantly lower in autistic children than controls. (tubitak.gov.tr)
  • For subjects suffering from reduced absorptive capacity, it can be an option to consume protein in hydrolyzed form to facilitate the uptake of essential amino acids [ 1 ]. (springer.com)
  • Twelve can be synthesised from other amino acids, but eight cannot and are referred to as essential amino acids and must be found in our diet . (docbrown.info)
  • Of these, 8 were substitutable and 9 essential amino acids. (who.int)
  • La spectrométrie de masse en tandem, les technologies moléculaires et l'analyse biochimique ont été utilisées pour les besoins du dépistage. (who.int)
  • Estimations of vitamins A and E, vitamin D and ferritin, folic acid and thyroid-stimulating hormone (TSH) were carried out by the methods described. (who.int)
  • Ferritin, folic acid and TSH were measured in serum by immunoradiometric assay (IRMA), charcoal boil and double antibody assay kit (DPC, Los Angeles, California), respectively. (who.int)
  • 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)
  • Here, the concentrations of amino acids from two particles from different touchdown sites (TD1 and TD2) are reported. (nature.com)
  • P contained 66.1% carbohydrate, 35.3% protein and 2.1% uronic acid and ranged in molecular weight from 850 to 20,000 Da. (scirp.org)
  • Members of the institute have published in a wide range of peer-reviewed journals, including Nature, Molecular Cell, Angewandte Chemie, JACS, Science Advances, Proceedings of the National Academy of Sciences USA, Nucleic Acids Research, Chemical Science and many others. (le.ac.uk)
  • The mass spectrometer ionizes the derivatized amino acids, generating charged ions that are subsequently analyzed based on their mass-to-charge ratio (m/z). (pharmiweb.com)