Quantitative Determination of the α-Amylase Inhibitor from Phaseolus Vulgaris using size Exclusion High-Performance Liquid Chromatography

Abstract

A quantitative determination of the α-amylase inhibitor from kidney beans, a glycoprotein (MW 49,000), by the use of a TSK-SW 3000 column is described. A correlation coefficient of 0.986 was obtained when the HPLC method was compared with a biological assay using Beckman Enzymatic Amylase-DS Reagent Kit. The within-day and between-day coefficients of variation were 4.8-8. 9% and 3.7-11. 6%, respectively. The results indicate this method is a reliable assay that has advantages over the biological assays presently available.     

High Performance Liquid Chromatographic Determination of Neomycin in Milk Using a Hisep Column

Abstract

A high performance liquid chromatographic (HPLC) method for the determination of neomycin in milk is described. Milk is passed directly through an amberlite CG-50 ion exchange resin column, and the neomycin which is retained on the column is derivatized with ortho-phthalaldehyde (OPA) reagent. The derivatized neomycin is eluted from the column with potassium borate buffer/methanol and analyzed by HPLC. A HISEP HPLC column with fluororoetric detection was used. Recoveries ranged from 94 to 102% in samples fortified between 0.1 to 5ppra levels. The detection limit is 50ppb.     

High-Performance Liquid Chromatographic Determination of Lasalocid Sodium in Chicken Tissue

Abstract

A high-performance liquid chromatographic (HPLC) method with fluorometric detection has been developed to determine lasalocid sodium(Fig.1) residues in chicken tissues. Lasalocid sodium was extracted from tissues by homogenizing them with methanol, purified by silicagel cartridge column and separated by HPLC using an ODS column.     

Recycling HPLC of p-Bromophenacyl Esters of Saturated C35–56 Fatty Acids from Mycobacterium Tuberculosis H37Ra on a Silica Column

Abstract

The p-bromophenacyl esters of saturated C_35–56 fatty acids from Mycobacterium tuberculosis H37Ra were separated according to structural classes on a silica column by high performance liquid chromatography (HPLC). The sample was cycled five times during HPLC. Highly purified C_35–38 esters were obtained by this method. Further HPLC fractionation on a reverse-phase column (C₁₈-bonded silica) gave complete separation of most of the remaining fractions. By combining mass spectrometry with HPLC separations, many of the fatty acid esters were tentatively identified.     

Differential Measurement of Cortisol and Cortisone in Human Saliva by HPLC with Uv Detection

Abstract

Both cortisol and its dehydro metabolite cortisone are present in normal human saliva. A method for differential Measurement of both compounds in 1 ml samples of saliva by HPLC/UV is described. the method uses an extraction column having a cyclodextrin bonded phase to retain the compounds of interest while allowing elution of interfering compounds. A steroid-bearing fraction is eluted from the cyclodextrin column, dried, reconstituted in a weak mobile phase, and injected on a reversed phase HPLC/UV system provided with an injector-mounted reversed phase extraction column. Samples containing corticosteroid concentrations as low as 0.5 ng/ml can be effectively analyzed by this method.     

Isolation of Glycolipids from Blood Elements

Abstract

Several chromatographic e.g. HPTLC, HPLC, etc. methods have been published in the literature for the separation, after sufficient pretreatment, of derivatized or non-derivatized glycolipid samples.

Our task is the extraction, isolation and separation of the glycolipids from different blood elements, followed by suitable fractionation methods, giving the lipid classes in sufficient purity and quantity for HPLC, HPTLC and OPTLC measurements and possibly further biochemical use.

We show the differences between the procedures commonly used and that developed in our laboratory.

The advantage of our method, which employs 3 cm long Brownlee Labs HPLC cartridges, is that it can be automated, it gives class fractionation of the lipid samples and as it is hardware compatible with HPLC equipment it can be used directly in a coupled column system for on line separation in the individual class. The development of this column coupling method for the fractionation of a given lipid class from the total lipid extract on an analytical column is under development.     

Separation of Methylated Purines by High Pressure Liquid Chromatography

Abstract

This paper reports a method for the separation and measurement of methylated purines of interest to carcinogenesis studies by high-pressure liquid chromatography (HPLC) following their column chromatographic isolation from collected urine samples. HPLC was evaluated on three different cation-exchange columns, with optimum conditions obtained on a Partisil 10-SCX column employing isocratic elution with 0.25M (NH₄)H₂PO₄ at pH 4.0. This column was also found to be useful for the separation of mono-methylguanine isomers. Application is shown to the analysis of rat urine following animal treatment with methyl methanesulfonate.     

A Rapid Method For Cyclosporine A Determination By Hplc

Abstract

A rapid method is described for the determination of cyclo-sporine in whole blood by HPLC. The cyclosporine is extracted with an acetonitrile-isopropanol mixture, purified on a C₁₈ minicolumn, and finally injected on a CN column. Recovery of the drug is greater than 90%.     

Solid Phase Extraction and HPLC Analysis of Tryptamide in Plasma

Abstract

A method for extraction and quantification of tryptamide in plasma is described in this report. The method employs Amberlite XAD-2 column extraction followed by HPLC with ultraviolet detection. The procedure is simple, rapid and reproducible. It has been applied to the measurement of tryptamide in plasma of rats dosed orally with this antiinflammatory and analgesic compound.     

HPLC Determination of Cyclosporine in Whole Blood

Abstract

A rapid sensitive method for measuring cyclosporine concentration in whole blood by HPLC has been developed. The pre-chromatography isolation steps are convenient and rapid and are based on salting out acetonitrile with simultaneous extraction of cyclosporine from the blood. A reversed phase column is used with detection by absorbance at 200 nm.     

Determination of Solasodine in Fruits of Solanum Khasianum by a Combination of Chromatofuge and High-Pressure Liquid Chromatography

Abstract

An extract of Solanum khasianum fruits was fractionated with a chromatofuge. The fraction containing solasodine was applied to a HPLC column and the effluent was monitored by UV. The peak height gave an accurate measure of the amount present. The efficiency and load capacity of the chromatofuge, as well as the accuracy and precision of the HPLC method were determined.     

Comparison of Two Methods of Ascorbic Acid Determination in Vegetables

Abstract

Vegetables (broccoli, Brussels sprouts, cauliflower, green beans, spinach, and turnip) were analyzed for ascorbic acid using a modified AOAC method and compared to a high performance liquid chromatography (HPLC) method. The HPLC method employed a weak ion exchange μBondapalc NH₂ column and detection at 254 nm. The two methods did not differ in ascorbic acid values for fresh and three-week stored broccoli, cauliflower, green beans, turnip and three-week stored Brussels sprouts and spinach. A higher ascorbic acid content was found for fresh Brussels sprouts and spinach when measured by the HPLC method.     

Rapid Amino Acid Analysis in Biotechnology: Determination of Alanine and Aspartic Acid

Abstract

A fast and sensitive chromatographic method was developed to monitor the enzymatic conversion of aspartic acid into alanine in a membrane reactor. The amino acids were converted into dansyl derivatives which were separated by ion-pair chromatography on a reversed-phase column and detected by fluorimetry using only conventional HPLC equipment.     

A Rapid HPLC Analysis of Diazepam in Animal Feed

Abstract

A rapid HPLC analysis is described for the methanolic extraction of diazepam from spiked animal feed. A short disposable reverse-phase extraction column is employed to remove interfering substances present in the animal feed. This is followed by direct injection of an aliquot into an analytical ODS column. The precision is better than 3.9% and the % recovery is 87.8 ± 0.8% resulting in a convenient, rapid method for the routine analysis of added diazepam in prepared animal diets.     

High-Performance Liquid Chromatographic Determination of TCNB in Potatoes

Abstract

A high-performance liquid chromatographic (HPLC) method was developed for the determination of TCNB (tetrachloronitrobenzene), a sprout inhibitor, in potato peels and flesh fortified at levels of 0.16 to 53.5 ppm. TCNB was analyzed on a u Bondapak C₁₈ column with UV detection at 210 nm. The mobile phase was acetonitrile-methanol-water (35:35:30) at a flow rate of 1.0 ml/min. Retention time was approximately 10 min. TCNB was extracted by blending for 5 min in acetone. Samples at a level of 1 ppm or higher were directly injected whereas samples below 1 ppm were partitioned into hexane followed by passage through an alumina column. Average recoveries varied from 85.6 to 96.8% with coefficients of variation ranging from 2.18 to 11.68%. A study conducted to test 23 pesticides for possible interferences with TCNB demonstrated that none of them co-chromatographed. The lower limit of detection was 0.08 ppm.     

HPLC Determination of Oxalic Acid in Cocoa

Abstract

An HPLC method is described for the determination of oxalic acid in cocoa and milk chocolate. Samples are extracted using 6N HCI; after extraction the pH of an aliquot is adjusted to 6.0 and interfering substances are eliminated through the use of a C₁₈ Sep-pak®. The final HPLC determination uses a monolayer reversed phase column with an ion-pairing mobile phase and electrochemical detection. The results indicate excellent accuracy and precision.     

Rapid Determination of Aldehydes in Air Analyses

Abstract

A simple analytical method for aldehyde determinations in ambient air is described. The method involved trapping the aldehydes as their DNPH derivatives in acetonitrile solution and then direct injection and analysis of the resulting solution on a reversed phase HPLC column with simultaneous detection at 254 and 360 nm. Several comparison studies are described.     

Use of an Internal Standard to Assay 6 β-Hydroxycortisol in Urine

Abstract

Currently 6 β-hydroxycortisol is assayed by radio-immunoassay or high performance liquid chromatography techniques. We have developed an HPLC method, utilizing gradient elution and an internal standard {a 4-pregnene-tetrol-3-one}. In this way, accuracy and sensitivity of the assay were greatly improved and allowed the application of this modified method for monitoring the time-course of hepatic microsomal enzyme activity.     

High Performance Liquid Chromatographic Determination of Emetine in Corn

Abstract

A High performance liquid chromatographic (HPLC) method for the quantitative analysis of emetine in corn is described. Corn kernels are removed from the ears, blended, and extracted with methanol. The extract is filtered through a 0.45 um Acrodisc filter and analyzed by HPLC using a LC-18-DB column. For detection, a fluorescence detector set at excitation of 285 and emission at 316 nm is used. The recoveries of samples fortified between 0.1 ppm to 20 ppm with emetine ranged from 95.5% to 103.3%.     

Quantitative HPLC Analysis of Plasma Amino Acids as Orthophthaldialdehyde/Ethanethiol Derivatives

Abstract

A reverse phase high performance liquid chromatographic method for the analysis of plasma amino acids is described. The method employs pre-column derivatization with o-phthaldialdehyde using ethanethiol as the reducing agent. The analysis shows good linearity and reproducibility. An average overall difference of 12% was seen for results obtained by the HPLC method versus those obtained with an amino acid analyzer. The chromatographic parameters of buffer concentration and column temperature were also examined.