Simultaneous Measurement of Diphenylhydantoin and Primidone in Serum by Gas—Liquid Chromatography

1970 ◽  
Vol 16 (2) ◽  
pp. 107-110 ◽  
Author(s):  
M A Evenson ◽  
P Jones ◽  
B Darcey
Keyword(s):  
Liquid Chromatography ◽  
Clinical Chemistry ◽  
Chemistry Laboratory ◽  
Specific Method ◽  
Gas Liquid Chromatography ◽  
Serum Samples ◽  
Large Numbers ◽  
Clinical Chemistry Laboratory ◽  
Isothermal Gas

Abstract The need for simultaneous determination of the concentration of diphenylhydantoin (Dilantin) and primidone (Mysoline) in serum is frequently expressed to the clinical chemistry laboratory. Isothermal gas-liquid chromatography (GLC) has been used to develop a rapid, specific method. The method involves a single extraction and no derivative formation. The procedure is simple enough to be used with large numbers of samples. Detection limits for the method are 0.3 µg diphenylhydantoin per ml and 0.1 µg primidone per ml. The mean precision of the method is 6.2% and 4.8%, expressed as the coefficient of variation, for diphenylhydantoin and primidone, respectively. Barbiturates and glutethimide added to serum samples did not interfere with the analysis. The method has been used for more than 500 patients without interferences from metabolites, and meets all criteria for routine and emergency use.

Feasibility of Multiple Simultaneous Enzyme Assays, for Diagnostic Purposes, with the GeMSAEC Fast Analyzer

1971 ◽  
Vol 17 (8) ◽  
pp. 715-720 ◽  
Author(s):  
Thomas O Tiffany ◽  
George F Johnson ◽  
Max E Chilcote
Keyword(s):  
Large Scale ◽  
Experimental Approach ◽  
Clinical Chemistry ◽  
Chemistry Laboratory ◽  
Large Numbers ◽  
Coefficients Of Variation ◽  
Clinical Chemistry Laboratory ◽  
Analytical Variation ◽  
Instrumental Precision

Abstract The GeMSAEC fast analyzer provides the clinical chemistry laboratory with an analytical instrument that can be used to perform large numbers of kinetic enzyme analyses. Precise enzyme-rate analyses can be done routinely, on a large scale, and at a decreased cost per test. Improved precision in analyses of enzymes should provide more reliable data because analytical variation is lessened. We have asked how the fast analyzer might provide more useful diagnostic information to the clinician. We have selected the ratio of SGOT to SGPT activity in serum as an example, and examined instrumental precision. The coefficients of variation of the ratio, determined in the range of 50 and 140 Karmen units (which represents slightly elevated to clearly elevated values), are 4.8% and 2.2%, respectively. We examined the feasibility of measuring two or more enzyme activities simultaneously in one sample, to produce a diagnostic enzyme profile. Determination of SGOT, SGPT, and GLDH in parallel is presented as an example. In addition, we illustrate spectrophotometric linearity at 340 nm and discuss instrumental noise and an experimental approach to determining it by use of a premix experiment.

Micro-Determination of p-Hydroxybenzoic Esters in Pharmaceuticals and Cosmetics

1977 ◽  
Vol 60 (1) ◽  
pp. 56-59 ◽  
Author(s):  
Emil Weisenberg ◽  
Baruch Gershon ◽  
Judith Schoenberg
Keyword(s):  
Liquid Chromatography ◽  
Phosphate Ester ◽  
Specific Method ◽  
Gas Liquid Chromatography ◽  
Direct Extraction ◽  
Flame Photometric Detector ◽  
Phenol Derivatives ◽  
Margin Of Error ◽  
Diethyl Phosphate

Abstract A rapid and specific method is described for the determination of microamounts of methyl, propyl, and butyl p-hydroxybenzoic esters (parabens) in pharmaceuticals and cosmetics. The method involves the direct extraction of parabens into benzene or chloroform followed by derivatization with phosphorochloridate. The diethyl phosphate ester derivatives are cleaned up on a Florisil minicolumn and finally measured by gas-liquid chromatography on 5% OV-210 on Gas-Chrom Q. A flame photometric detector or a KCl thermionic detector may be used. The concentration response was linear up to 40 ng parabens. The reproducibility and margin of error were tested with fortified samples. This method may be applied to the estimation of other phenol derivatives.

Quantitative Identification of Urinary Calculi

1955 ◽  
Vol 1 (4) ◽  
pp. 241-248 ◽  
Author(s):  
Reid H Leonard ◽  
Arthur J Butt
Keyword(s):  
Oxalic Acid ◽  
Quantitative Determination ◽  
Clinical Chemistry ◽  
Urinary Calculi ◽  
Ammonia Nitrogen ◽  
Chemistry Laboratory ◽  
Calcium Phosphorus ◽  
Clinical Chemistry Laboratory ◽  
Quantitative Identification

Abstract Quantitative determination of calcium, phosphorus, and oxalic acid, assisted by occasional determination of ammonia nitrogen and insoluble nitrogen when indicated by qualitative tests, provides a means of computing the component substances of calculi. The determinations may be performed by slight modifications of the methods in use in the routine clinical chemistry laboratory, although flame photometry is particularly convenient for the determination of calcium.

Determination of Diazepam (Valium) Concentrations in Serum by Gas—Liquid Chromatography

1970 ◽  
Vol 16 (3) ◽  
pp. 177-179 ◽  
Author(s):  
Lowell B Foster ◽  
Christopher S Frings
Keyword(s):  
Liquid Chromatography ◽  
Chromatographic Method ◽  
Gas Liquid Chromatography ◽  
Gas Chromatograph ◽  
Serum Samples ◽  
The Many ◽  
Gas Chromatographic Method

Abstract A simple, rapid, and precise gas chromatographic method for determination of serum diazepam concentrations is described. Two milliliters of serum is extracted with chloroform, and the extract is concentrated and injected into a gas chromatograph. Of the many drugs and serum samples tested, none interferes with the determination of diazepam.

Monitoring drug concentrations in a case of combined overdosage with primidone and methsuximide.

1976 ◽  
Vol 22 (6) ◽  
pp. 915-921 ◽  
Author(s):  
G F Johnson ◽  
C J Least ◽  
J W Serum ◽  
E B Solow ◽  
H M Solomon
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Liquid Chromatography ◽  
Gas Chromatography Mass Spectrometry ◽  
Gas Liquid Chromatography ◽  
Therapeutic Decision ◽  
Serum Samples ◽  
Monitoring Drug ◽  
Drug Concentrations

Abstract We describe a case of fatal overdosage with primidone and methsuximide. During the early phase of the patient's hospital course we found concentrations of methsuximide, N-desmethylmethsuximide, and primidone in serum that far exceeded the usual therapeutic concentrations, as determined by gas-liquid chromatography. Determination of N-desmethylmethsuximide in peritoneal fluid demonstrated concentrations comparable to those in serum. This led to the therapeutic decision to manage the patient by dialysis. Subsequently, serum samples collected during the course of hospitalization were analyzed quantitatively by gas-liquid chromatography for methsuximide, N-desmethylmethsuximide, primidone, phenobarbital, and diphenylhydantoin. Selected serum specimens were also analyzed by gas chromatography-mass spectrometry, and N-methyl-2-hydroxymethyl-2-phenylsuccinimide, a metabolite of methsuximide not previously described in human serum, was identified by analysis of its mass spectrum.

An enzymic assay for the specific determination of methanol in serum.

1987 ◽  
Vol 33 (12) ◽  
pp. 2204-2208 ◽  
Author(s):  
B Vinet
Keyword(s):  
Clinical Chemistry ◽  
Alcohol Oxidase ◽  
Chemistry Laboratory ◽  
Enzymatic Method ◽  
Specific Determination ◽  
Reaction Proceeds ◽  
Clinical Chemistry Laboratory ◽  
Enzymic Assay ◽  
True Values

Abstract This method for the specific determination of methanol in serum is based on the following two reactions: (formula; see text) Alcohol oxidase is not specific: it converts all lower alcohols to their corresponding aldehydes; however, formaldehyde dehydrogenase is specific and thus the transformation of NAD+ to NADH (which is used to monitor the reaction) proceeds only if methanol is originally present in the sample. The method was automated with a Roche COBAS FARA centrifugal analyzer. The calibration curve is linear between 0.6 and 12 mmol/L. The detection limit is about 0.6 mmol/L. The CV is 4.6% for a concentration of 3 mmol/L. When 55 serum specimens known to be free of methanol were supplemented with known amounts of methanol and analyzed by the enzymatic method, the results correlated well (r = 0.987) with the true values, the regression equation being: y = 1.016x + 0.661, where x represents the true values. Results are not affected by other alcohols that may be present in serum, by methanol metabolites, or by some commonly prescribed drugs. The major advantage of this new assay is that it can be used 24 h a day in any clinical chemistry laboratory.

Quantitative Determination of Benzaldehyde in Flavors by Gas-Liquid Chromatography

1963 ◽  
Vol 46 (6) ◽  
pp. 950-951
Author(s):  
Richard L Brunelle ◽  
Glenn E Martin
Keyword(s):  
Liquid Chromatography ◽  
Liquid Phase ◽  
Benzoic Acid ◽  
Quantitative Determination ◽  
Solid Support ◽  
Specific Method ◽  
Gas Liquid Chromatography ◽  
Ultraviolet Spectrophotometry ◽  
Liquid Chromatography Separation

Abstract A rapid and specific method is given for determination of benzaldehyde in the presence of interfering substances by gas-liquid chromatography. Separation is effected on a ¼ column containing 2 5% Apiezon M as the liquid phase on a solid support of Chromoport XXX (60—80 mesh) at isothermal conditions, 100°C. The determination can be performed in the presence of benzoic acid and other interfering substances. Results are compared with those obtained by ultraviolet spectrophotometry on a variety of almond and cherry flavors.

Determination of Calcium and Magnesium in Serum, Urine, Diet, and Stool by Atomic Absorption Spectrophotometry

1967 ◽  
Vol 13 (3) ◽  
pp. 204-214 ◽  
Author(s):  
Elizabeth G Gimblet ◽  
Amy F Marney ◽  
Roy W Bonsnes
Keyword(s):  
Atomic Absorption ◽  
Clinical Chemistry ◽  
Atomic Absorption Spectrophotometry ◽  
Chemistry Laboratory ◽  
Absorption Spectrophotometry ◽  
Clinical Chemistry Laboratory ◽  
Calcium And Magnesium

Abstract Atomic absorption spectrophotometry was evaluated as a method for the determination of calcium and magnesium in serum, urine, diet, and stool, and was found a most suitable technic for a large clinical chemistry laboratory.

scholarly journals Pre-analytical, analytical, and post-analytical considerations while processing samples of COVID-19 patients: Perspective from a clinical chemistry laboratory in India

2020 ◽  
Vol 11 (5) ◽  
pp. 112-115
Author(s):  
Saswati Das ◽  
Bidhan Chandra Koner
Keyword(s):  
Clinical Chemistry ◽  
Chemistry Laboratory ◽  
Therapeutic Monitoring ◽  
Serum Samples ◽  
General Management ◽  
Resource Limited ◽  
Clinical Chemistry Laboratory ◽  
The City ◽  
Limited Setting

Background: Since its detection in December 2019 in the city of Wuhan, China, the COVID-19 pandemic has grappled the world. Laboratories have been central in the diagnosis, prognosis and therapeutic monitoring of COVID-19 patients. With this pandemic spreading, laboratory personnel have become vital in the efforts to halt the advance of the virus. Aims and Objective: In this article, we will address various concerns in all the three phases of testing of the COVID-19 blood and serum samples in a clinical chemistry laboratory and discuss the issues pertaining to a resource-limited setting. Materials and Methods: International, national and regional guidelines on bio-safety and operational management available at the time of preparation of this manuscript were analyzed. Additionally, literature search through PubMed was done on the keywords “bio-safety”, “pre-analytical”, “analytical”, “post-analytical” and “COVID-19”. Results: The pre-analytical, analytical, post analytical, general management problems we faced in our laboratory and the best practices that we followed to address the same has been included in this paper. Conclusion: Some unprecedented challenges the laboratories have encountered during this outbreak are maintaining the lab safety of highest standards, management of human resource while sustaining the quality of testing. Laboratories will have to constantly innovate in order to meet the demands of this outbreak.

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