摘要:

A novel potentiometric enzyme immunoassay technique, utilizing polystyrene beads In conjunction with a gas sensing membrane electrode, is described. The technique is illustrated with the measurement of digoxin via competitive inhibition of anti-digoxin-horseradish peroxidase conjugate activity. The use of the gas sensing electrode permits polystyrene beads to be used without concern for turbidity In the measurement system. The method is convenient, inexpensive, and yields sensitivities In the nanogram range.

ISSN:0003-2719    

DOI:10.1080/00032718508066920

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Thallium (III) sulfate in dilute sulfuric acid quantitatively oxidizes isoniazid to nitrogen and 4-pyrldine carboxylic acid. The test material is reacted with a measured excess of the reagent, the residual amount being back-titrated with ascorbic acid using o-dianisidine or p-ethoxychrysoidine as indicator. 4-Aminosalicylic acid, thiacetazone, thiamine hydrochloride, lactose and a number of other excipients do not Interfere with the analysis.

ISSN:0003-2719    

DOI:10.1080/00032718508066921

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The use of first derivative spectrophotometry for the simultaneous determination of certain drugs in multicomponent formulations is presented. The method is illustrated by the determination of antazoline hydrochloride, phenylephrine hydrochloride and ephedrine hydrochloride in eye drops and acepifylline, phenobarbitone and papaverine hydrochloride in suppositories. These selected applications illustrate the relative ease and simplicity offered by first derivative spectrophotometry for the assay of three-component mixtures with spectral interferences from matrix formulations.

ISSN:0003-2719    

DOI:10.1080/00032718508066922

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A rapid spectrofluorimetrio method for the analysis of khellin and visnagin in fruits and liquid extract of Ammi visnaga has been described. Khellin is determined fluorimetrically in chloroform, where visnagin exhibits no contribution. The latter is estimated by measuring its fluorescence in ethanol, where khellin shows no interference. The method is highly selective and can be performed without prior separation of the individual furanochromones. The sensitivity range is 1 - 5 ug ml−1for each compound. The method was successfully applied to the analysis of khellin and visnagin in laboratory-made mixtures, fruits and liquid extract of Ammi visnaga.

ISSN:0003-2719    

DOI:10.1080/00032718508066923

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A modified ion pair reverse-phase high-performance liquid chromatographic (HPLC) method for examining 5-fluorouracil levels in human serum was developed. The method employs the use of an internal standard and an organic extraction procedure. An isocratic mobile phase consisting of tetraethylammonium bromide, tetrabutylammonium hydrogen sulfate, methanol, sodium acetate, and phosphate buffer was used at a flow rate of 0.7 ml/min. 5-Fluorouracil was detected by UV absorption at a wavelength of 266 nm. The HPLC method described is a convenient and sensitive assay for examining 5-fluorouracil concentration in human serum.

ISSN:0003-2719    

DOI:10.1080/00032718508066924

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

An analytical method has been developed to quantitate diethyldithiocarbamate (DDTC) in plasma by derivatization and HPLC analysis. A plasma sample is rapidly derivatized by addition of 10 ul of Meerwein's reagent (Et3O+BF4−) in methylene chloride. The resulting S-ethyl diethyldithiocarbamate is extracted into chloroform containing S-isopropyl diethyldithiocarbamate as the internal standard. Concentrations of DDTC are then determined by reverse phase HPLC analysis with detection at 254 nm. The detection limit for DDTC as the S-ethyl ester is 5 ng/ml. The chromatographic response is linear over the range of 250 to 500,000 2 ng/ml (R2< 0.9995). This method has been used to determine DDTC plasma levels in animal models prior to clinical use of DDTC as a kidney rescue agent for patients receivingcis-diamminedichloroplatinum(II) (Cisplatin) chemotherapy.

ISSN:0003-2719    

DOI:10.1080/00032718508066925

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

This paper presents several very sensitive fluorimetric-FIA methods for determination of pyridoxal and pyridoxal-5-phosphate based on their oxidation in the presence of cyanide. Calibration curves have been run over the concentration range of 2.5×10−8- 1.0×10−3M (5.0 ppb-203.6 ppm and 6.3 ppb-265.2 ppm, respectively) finding an r.s.d. of 0.3% and a sampling rate of 25 samples. h−1for both species. The presence of NAD is tolerated up to a 336 and 194 fold amount, respectively, for each compound.

ISSN:0003-2719    

DOI:10.1080/00032718508066926

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The method is amyloclastic in nature and use cross-linked (CL)-amylose and CL-starch as specific insoluble substrates for α-amylase only and not for exoamylases. α-Amylase is allowed to act on the CL-substrate liberating soluble polysaccharide chains, large enough and in a suitable conformation to allow the formation of iodine inclusion complexes. Unlike the classical iodometric methods, the reaction is followed by an Increase In iodine color. The method has much in common with the well known chromogenic (PhadebasR) methods, Both, use insoluble substrates (ß-limit amyloses) which are not susceptible to attack by exoamylases and in both cases the enzymatic reaction is followed by the release of soluble polysaccharide chains. These soluble polysaccharide released chains are in linear dependence with the enzyme concentrations. The CL-amylose and CL-starch tablets are prepared such as to allow a quick disintegration. One tablet in two ml water and 0.1 ml α-amylase sample should be incubated for 3 min. The reaction is stopped with 1 ml of 1N HC1. 6 ml of 2mM iodine reagent is added and the absorbance is measured at 570 nm, The new method was calibrated against the usual methods for -amylase determination, as reference tests.

ISSN:0003-2719    

DOI:10.1080/00032718508066927

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

One widely used procedure -for immobilizing enzymes on nylon was first described by D.L. Morris,et. al.in 1975 (Biochem. J.,147, 153). This report describes the optimization of this procedure, leading to a reduction in reaction time from 20 hours to 80 minutes and concomitant increase in the activity of the open-tubular reactors by as much as a factor of four. Type 66 nylon reactors holding three different enzymes, glucose oxidase, catalase, and urease, were prepared by the modified procedure and tested in a segmented continuous flow instrument.

ISSN:0003-2719    

DOI:10.1080/00032718508066928

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A multiple enzyme method for spectrophotometrical measurement of K, Na ATPase activity is described. The method includes three enzymatic steps: Hydrolyses of ATP by ATPase, conversion of inosine to hypoxanthine and ribose -1- phosphate by purine nucleoside phosphorylase and finally xanthine oxidase mediated oxidation of hypoxanthine to xanthine with consequent formation of formazan from a tetrazolium salt. The phospholytic cleavage of inosine in the medium is dependent of an ATPase- phosphate complex.

ISSN:0003-2719    

DOI:10.1080/00032718508066929

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor