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1751469 
Journal Article 
Analysis Of Ethchlorvynol (Placidyl): Evaluation Of A Comparison Performed In A Clinical Laboratory 
Bridges, RR; Jennison, TA 
1984 
Yes 
Journal of Analytical Toxicology
ISSN: 0146-4760
EISSN: 1945-2403 
NIOSH/00147500 
8 
6 
263-268 
Common techniques for analyzing ethchlorvynol (113188) by colorimetry and gas liquid chromatography (GLC) were evaluated. A stock solution of ethchlorvynol was used to prepare standard curves in drug free human plasma, whole blood, and urine. Samples and standards of plasma or whole blood were deproteinized by precipitation with 10 percent trichloroacetic-acid (76039) (TCA) or with 10 percent sodium-tungstate (11120017) (whole blood only). After heating, the mixtures were filtered. Two milliliters (ml) of filtrate were added to 2ml of the color reagent diphenylamine (122394) in concentrated sulfuric-acid and glacial acetic-acid. After 20 minutes absorbance was determined at 510 nanometers using blanks that had been carried through the precipitation procedures. For GLC, samples and standards were extracted into chloroform, and 2 to 4 microliters of extract were analyzed. Absolute recovery of ethchlorvynol was strongly dependent on the matrix being tested (serum/plasma, whole blood, urine), the precipitation reagent selected (TCA or sodium-tungstate), and the methodology performed (colorimetric or GLC). Because of these differences it was necessary to prepare appropriate standard curves in corresponding matrices using drug free plasma for tasting plasma, drug free blood for testing blood, and water for urine quantitation. Precipitation of protein by TCA was effective if performed at 60 degrees-C. Reducing the amount of sodium-tungstate to 0.9ml along with 3.15ml deionized water delayed the formation of an interfering precipitate by 12 to 16 hours. GLC was particularly valuable in the analysis of ethchlorvynol in urine because of its ability to distinguish ethchlorvynol from its hydroxylated metabolite. The authors conclude that the two analytical techniques are equivalent in their performance, provided that matrices, precipitation reagents, and methodologies are consistent through each procedure. 
DCN-134385; Analytical methods; Analytical processes; Toxic effects; Monitoring systems; Toxins; Clinical chemistry; Toxicology; Laboratory equipment; Laboratory techniques; Analytical chemistry