Preparation of an immunoaffinity column with amino-silica gel microparticles and its application in sample cleanup for aflatoxin detection in agri-products. (65/78)

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Comparative study of chromatographic medium-associated mass and potential antitumor activity loss with bioactive extracts. (66/78)

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Cellulose 2,3-di(p-chlorophenylcarbamate) bonded to silica gel for resolution of enantiomers. (67/78)

In this study, 6-azido-2,3-di(p-chlorophenylcarbamoylated) cellulose was synthesized and bonded onto aminized silica gel to obtain a new chiral stationary phase. Enantioselectivity of the chiral stationary phase and Chiralcel OF suggested promising chiral separation ability of the new cellulose chiral stationary phase. In addition, the effect of trifluoroacetic acid, diethylamine on enantioselectivity and retention factors on the chiral stationary phase in high performance liquid chromatography was investigated. Experimental results revealed that resolution increased as the trifluoroacetic acid concentration increased to 0.3% while resolution declined as the diethylamine concentration increased. Therefore, the optimal concentrations of trifluoroacetic acid and diethylamine were determined to be 0.3 and 0.1%, respectively. In most cases, trifluoroacetic acid shortened the retention of the first eluted enantiomer while it increased the retention of the other. For acidic compounds, with the existence of diethylamine in the mobile phase, the retention of both enantiomers decreased. But for basic compounds, the retention of both enantiomers increased.  (+info)

Rapid analysis of 2-alkylcyclobutanones in irradiated meats, cheese and salmon by direct solvent extraction followed by GPC. (68/78)

2-Alkylcyclobutanones (2-ACBs) are recognized as a marker of irradiation in lipid-containing food products. Here, a rapid method for the analysis of 2-dodecylcyclobutanone (2-DCB) and 2-tetradecylcyclobutanone (2-TCB) in irradiated food products using direct solvent extraction (DSE) was developed, and the extraction efficiency was compared to that of the Soxhlet extraction method (EN 1785), which is the official method for this analysis. Briefly, 2-ACBs were extracted either by using a Soxhlet apparatus or by DSE with n-hexane. The lipid extract was purified by GPC followed by a silica gel cartridge column. Finally, 2-DCB and 2-TCB were measured using GC-MS/MS. The extraction efficiency of 2-ACBs by the DSE method was similar to that of the Soxhlet extraction method. The trueness of 2-DCB and 2-TCB spiked at 50 ng/g in lipid extracts of beef, pork, chicken, cheese and salmon with the proposed method were 76.6% to 91.6% and 81.3% to 109.0%, respectively. The limits of detection for 2-DCB and 2-TCB in lipid extracts were 15 and 20 ng/g, respectively.  (+info)

Immobilization of cross-linked phenylalanine ammonia lyase aggregates in microporous silica gel. (69/78)

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Organically modified silica with pyrazole-3-carbaldehyde as a new sorbent for solid-liquid extraction of heavy metals. (70/78)

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Tricarboxylate carrier of bovine liver mitochondria. Purification and reconstitution. (71/78)

The tricarboxylate carrier of bovine liver mitochondria has been solubilized by Triton X-114 and purified by chromatography on hydroxylapatite and Silica Gel 60. The purified carrier could be visualized as a single band in polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate with Mr 37,000-38,000. The carrier, after reconstitution in phospholipid vesicles, catalyzed the exchange of [14C]citrate against citrate, malate, and threo-D8-isocitrate and was inhibited by the specific tricarboxylate carrier inhibitor 1,2,3-benzenetricarboxylic acid.  (+info)

Elimination of silica gel from gangliosides by using a reversed-phase column after preparative thin-layer chromatography. (72/78)

A simple and effective procedure has been developed for eliminating silica gel from gangliosides after preparative thin-layer chromatography. Gangliosides were extracted from the scraped silica gel with chloroform-methanol-water 10:10:3 (by volume) and dried. The residue was suspended in 0.1 M NaCl and centrifuged. After filtration through a sintered glass funnel, the supernatant was applied to a reversed-phase column. The column was washed with 0.1 M NaCl, water, and methanol-water 1:1 (v/v). Gangliosides were eluted from the cartridge with methanol with yields of 92% and 90% in terms of dry weight and sialic acid content, respectively. Almost all of the silica gel contamination was eliminated from gangliosides by this procedure.  (+info)