Sensitive and selective method for the determination of chlormezanone in plasma by electron-capture gas chromatography

A sensitive and selective determination method of chlormezanone in plasma has been divised. Chlormezanone in plasma was extracted with toluene at pH 4.5, and converted into p-chlorobenzaldehyde in 0.1 N NaOH. Using p-bromobenzaldehyde as an internal standard, the hydrolysis product and the internal standard were extracted with n-hexane, and the extract was concentrated in vacuo in the presence of isoamyl alcohol to prepare the sample solution. The sample solution was submitted to electron-capture gas chromatography. Chlormezanone was determined by use of the peak height ratio of p-chlorobenzaldehyde against the internal standard. The method was utilized successfully for pharmacokinetic studies of chlormezanone in plasma.