摘要:

A suitable TLC separation scheme for ten sulfa drugs on silica gel plates impregnated with copper salts, using the solvent system ethyl acetate-benzene (40:20), has been worked out. Dragendroff reagent was used as visualizing reagent for the plain silica gel plate. The impregnated plates were self visualized.

ISSN:0003-2719    

DOI:10.1080/00032718508066127

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A simple and reproducible method for the determination of cimetidine in serum is described. Separation and quantitation were performed by high-performance liquid chromatography using a Radial-Pak CN column with a mobile phase of 33 % acetonitrile solution containing 5 mM triethylamine (adjusted to pH 3.0 with phosphoric acid) at a flow rate of 2 ml/min and at a detection of 220 nm. Cimetidine and ranitidine as an internal standard were extracted from serum with ethyl acetate and then back-extracted into dilute acid. An aliquot of the dilute acid was analyzed in the chromatographic system. The limit of detection was as low as 0.02 μg/ml using 100 μl of serum at a signal-to-noise ration of 2. Recoveries of cimetidine and ranitidine from serum were both greater than 95%. Within-run and day-to-day reproducibility for 10.0 μg/ml samples were 2.6 % and 2.9 %, respectively. The method is applicable to pharmacokinetic studies.

ISSN:0003-2719    

DOI:10.1080/00032718508066128

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Cycloserine has been determined by a spectrophotometric method based on n → charge-transfer complex formation with chloranil. The method involves addition of cycloserine solution to chloranil reagent in borate buffer of pH 9; and heating at 65°C for 45 min. The complex formed exhibits absorption maximum of 348 nm; and Amaxis linearly related to concentration over the range 2–8 μg/ml. The mean percentage found for the authentic sample is 100.32 ± 0.70. When applied to commercial capsules claimed to contain 250 mg each, the mean percentage found is 102.45 ± 1.05. These results have shown good agreement when compared with those obtained by the pharmacopoeial (B.P.) methods.

ISSN:0003-2719    

DOI:10.1080/00032718508066129

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A method has been developed to simultaneously determine aspirin and salicylic acid in rat whole blood. Aspirin and salicylic acid are extracted from acidified whole blood into a 50/50 v/v ethylacetate/butylchloride organic solvent system containing internal standard (meta-anisic acid). Following controlled evaporation of the organic extract under partial vacuum, the dried residue is reconstituted with mobile phase. Chromatography is ion suppression reverse phase on a 5 μm octyldecasiland column with detection by UV absorbance at 280 nm. In this method, the procedure of blood centrifugation for plasma preparation is eliminated. Therefore, the blood volume required is decreased and the sensitivity of analysis is considerably increased. Concentrations of aspirin as low as 0.5 mcg/ml and salicyclic acid as low as 1.5 mcg/ml can be quantitated in as little as 100 μl of whole blood.

ISSN:0003-2719    

DOI:10.1080/00032718508066130

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

This paper recommends a useful procedure for digesting the blood sample and discusses the optimum working conditions for determinations of whole blood selenium and serum selenium by cathodic stripping voltammetry. The blood sample is heated with the mixture of HNO3-HClO4to destroy protein contents, and then HCl is used to reduce Se(VI) for the stripping measurement. Considering the matrix effects, the method of addition is preferred. Stripping peak potential, -0.5 v vs.Ag/AgCl. With the stripping peak current the linear working range for selenium is 0.1 – 12 ppb and 0.1 ppb is the detection limit. This method is highly sensitive, having fairly good repeatability. Coefficient of variation 3.97%. Recovery 91% – 108%. It has been applied to clinical analysis of which the results are satisfactory.

ISSN:0003-2719    

DOI:10.1080/00032718508066131

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The likelihood of erroneous results is very high when a single dose of ligand (e.g.dihydrotestosterone) is employed in the assay of sex hormone binding globulin (SHBG) using precipitation with ammonium sulfate. However, correct results will be obtained if several ligand doses are used and the calculations are based on a Scatchard plot from which non-specific binding has been eliminated. The reliability of such a multiple-dose SHBG assay was tested. As established by an analysis of variance, the results of the measurements were independent of the volume assayed. Furthermore, by assaying 25 plasma sample in duplicate, an average within-assay coefficient of variation of 5.5% was obtained. The assay of the same samples on different occasions gave an estimate of between-assay variation ranging from 3.5% to 8.9% for various types of plasma. Moreover, the results of the assay of 170 plasma samples were well correlated (r = 0.8) with those obtained by a steady state electrophoresis. Thus the multiple-dose precipitation assay gives reliable results and is suitable for routine measurements of SHBG.

ISSN:0003-2719    

DOI:10.1080/00032718508066132

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

An enzymatic sensor was constructed from an oxygen amperometric sensor on whose surface a dialysis membrane containing covalently bonded catalase was set. Immobilization of the enzyme on the dialysis membrane surface was achieved with 2,4-dichloro-6-methoxy-s-triazine, a derivative of cyanuric chloride, which unlike others of its monosubstituted derivatives ensures some advantages. The time of measurement is less than 12 sec, for the kinetic method of the initial slope and one minute for the steady-state method. The sensor responds linearly to hydrogen peroxide in the concentration range 10−3- 10−5moles/1. The utilization of this sensor in intermittent and continuous operation in a laboratory enzymatic minireactor is discussed.

ISSN:0003-2719    

DOI:10.1080/00032718508066133

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A high-performance liquid chromatography assay was developed for the purpose of examining xanthine, hypoxanthine, uridine, thymidine, allopurinol, and oxypurinol in serum of patients with advanced carcinoma treated with methorexate and 5-fluorouracil. After the addition of an internal standard, serum samples were extracted of purines and pyrimidines with trichloroacetic acid and neutralized withtert-amine. Aliquots of the extracted serum were injected onto a C18 reverse-phase column and purines and pyrimidines were eluted with a gradient of MeOH/H2O and KH2PO4solutions. Absorbance was detected with a variable-wavelength UV spectrophotometer at 254 nm and 280 nm. This assay can be readily applied to quantitate baseline and treatment-induced variations in serum purine and pyrimidine levels which may correlate with clinical response and/or toxicity in patients with cancer.

ISSN:0003-2719    

DOI:10.1080/00032718508066134

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A Selective and sensitive assay of hypoxyanthine, xanthine and inosine by reversed-phase liquid chromatography coupled with immobilized enzyme reactors is described. The flourometric detection of hydrogen peroxide using immobilized peroxidase and p-hydroxyphenylacetic acid was applied to the assay of hypoxanthine, xanthine and inosine, which were oxidized to hydrogen peroxide in the presence of the immobilized enzymes (purine nucleoside phosphorylase and/or xanthine oxidase. The enzymes were immobilized the the intermolecular cross-linking method on controlled pore-glass. The method established was applied to serum and urine samples. The detection limits of hypoxanthine, xanthine and inosine were approximately 130, 300 and 650 pg per injection, respectively.

ISSN:0003-2719    

DOI:10.1080/00032718508066135

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Isotachophoresis, with its inherent high resolving power is a rapid and powerful technique for characterization of Hymenoptera insect venoms. By applying a combination of isotachophoresis for the first dimension separation step, and enzyme based assays, electrophoresis or immunological assays for the second dimension identification, it has been possible to identify the most important peptide/protein components in “Yellow Jacket” (Vespula species) venom. The combined two dimensional procedure is rapid, reproducible and well suited for determination of the antigenic/allergenic composition of various Hymenoptera venoms.

ISSN:0003-2719    

DOI:10.1080/00032718508066136

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor