摘要:

Although enantiomers normally have identical spectra, several methods for measurement of optical purity using NMR are possible: forming diastereomeric derivatives using chiral solvents and complexation with chiral reagents especially lanthanide shift reagents. The major limitation of these techniques as quantitative methods is the small chemical shift differences observed. However, with the availability of a wide range of lanthanide shift reagents, this problem is overcome. Several examples are cited for optical purity determinations of several pharmaceuticals using lanthanide shift reagents.

ISSN:0003-2719    

DOI:10.1080/00032718808059899

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Deliberately added hydrophilic salt contaminations behave as ion-exchange sites in the plasticized PVC membrane of a neutral carrier ion-selective electrode. The added salt does not influence the potenticmetric performance of the membrane. Since the membrane without added salt is itself an ion-exchanger, its ion-exchange capacity may be linked to ionizable hydrophilic impurities.

ISSN:0003-2719    

DOI:10.1080/00032718808059900

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A novel electrochemical method for analysis of glucosinolates is described. Glucose, released by the action of myrosinase on the analyte, is detected amperometrically by a glucose electrode having glucose oxidase immobilised on a platinised carbon base. The dependence of current responses on analyte concentration was linear up to 5mM for sinigrin and progoitrin, and the applicability of the method for determination of total glucosinolate in rape seed was demonstrated. An alternative approach was also examined which employed a bi-enzyme electrode made by co-immobilising the two enzymes on the same electrode.

ISSN:0003-2719    

DOI:10.1080/00032718808059901

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The actual fucose content of a glycoprotein or a polysaccharide can be determined without previous hydrolysis of the samples by extrapolating to zero time the curve obtained by plotting the amount of fucose against time of heating in sulphuric acid solution in the determination. Evidence is presented which indicates that fucose is not degraded by the acid treatment but by reaction with other compounds produced in the acid reaction medium.

ISSN:0003-2719    

DOI:10.1080/00032718808059902

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A simple enzymatic end point method for the determination of L-phenylalanine and 3-phenylpyruvate has been developed. The assay is based on the spectrophotometry determination of NADH formed or degraded in the reaction catalyzed with Thermoactinomyces intermedins phenylalanine dehydrogenase. This method enables the simple and selective determination of L-phenylalanine and 3-phenylpyruvate based on the high substrate specificity of the enzyme. The assay is sensitive in the range of 0.015−0.15 umol of L-phenylalanine and 3-phenylpyruvate.

ISSN:0003-2719    

DOI:10.1080/00032718808059903

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The adsorption of vitamin Ki at a hanging mercury drop electrode at pH 4.2 allows the determination of this compound in the 1 × 10−6M−1 × 10−9Mconcentration range. Applying a square-wave potential scan provides a 200-fold increase of the peak current compared to differential pulse stripping voltammetry. The influence of several operational parameters such as the nature and the pH of the supporting electrolyte, the deposition time and the potential are discussed. Interactions between the adsorbed molecules occur during the deposition step.

ISSN:0003-2719    

DOI:10.1080/00032718808059904

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A selective, sensitive, rapid and well reproducible TLC-densitometric method has been developed for simultaneous determination of sulphonamides (sulfamethoxazol, sulfadoxin, sulfamerazin, sulfametrol, sulfadiazin) in combination with trimethoprim in various dosage forms. The R. S. D. (%) is 1.09 to 1.82 for the sulphonamides and 1.1 for trimethoprim. The method is suitable not only for quantitative evaluation of sulphonamides and trimethoprim in all commercial drug forms (tablets, injections, suspensions, syrups, pulvis), but also for checking the identity of the active substances.

ISSN:0003-2719    

DOI:10.1080/00032718808059905

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Thiopental is an ultra-short acting barbiturate, used either to induce anesthesia, or to manage intracranial hypertension associated with head injuries. A high performance liquid chromatography method vas proposed for the rapid and easy determination of thiopental in biological fluids. After precipitation of proteins with acetonitrile the chromatographic separation vas performed onto a reversed-phase column with an acetonitrile-perchlorate buffer mixture as mobile phase. Compounds were analysed at 300nm and the detection limit vas about 0.1 mg/1. The analytical procedure vas applied to the therapeutic follow-up in patients (8 childrens. 4 adults) treated with long-term infusion of thiopental after head injury, and to a pharmacokinetic study in patients receiving a single 1Y bolus of thiopental to induce anesthesia.

ISSN:0003-2719    

DOI:10.1080/00032718808059906

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A Reverse-Phase HPLC method is described for the simultaneous identification and determination of 5 barbiturates: Allobarbital, Phencbarbital, Butabarbi -tal, Butalbital and Pentobarbital. Barbital is used as internal standard. The mobile phase is Milli Q Water/ Acetonitrile/ 1.75 M Phosphoric Acid (738:200:2, v/v/v) at a flow rate of 0.8 mL/min and UV detection is carried out at 195 nm. The single extraction procedure requires only small samples and analysis is quick.

ISSN:0003-2719    

DOI:10.1080/00032718808059907

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A rapid, selective and accurate high-performance liquid chromatography method (HPLC) for the determination of diltiazem hydrochloride using clonazepam as internal standard is developed. The investigated compounds were eluted from 5 u Micropak MCH-5 reversed phase column at ambient temperature with a mobile phase comprising of acetonitrile-water (48:52%) at pH 3.3 and containing 0. 01M sodium-n-octane sulfonate as an ion pairing substance. The mobile phase was pumped at a flow rate of 1 ml min−1and the effluent was monitored at 239 nm. The retention times of the internal standard and diltiazem were at 3 min and 9 min, respectively. A linear relationship was derived between the peak height ratio (diltiazem/clonazepam) and diltiazem concentration over the range 1–10 μg ml−1. Detection limit for the drug is 0.2 μg ml−1at 0.01 aufs. The developed procedure was applied to study the stability of diltiazem in the presence of its degradation products as well as in the presence of formulation excipients.

ISSN:0003-2719    

DOI:10.1080/00032718808059908

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor