Direct analysis of salicylic acid in keratolytic plaster by gas-solid chromatography.

A rapid gas-solid chromatographic method is reported for the direct analysis of salicylic acid in keratolytic plaster. The method requires no preseparation or derivatization and takes about 14 min. Since it requires only 2-7 mg of sample, it can determine the salicylic acid concentration in a particular area of plaster. The analyzing column is packed with porous polymer beads of 2,6-diphenyl-1,4-phenylene oxide. An automatic solid sampling system is used to connection with the gas chromatograph employing dual flame-ionization detectors. The average recovery of salicylic acid in synthetic samples containing 400-2700 microgram was 100.6 +/-1.6%. The average correlation coefficient of the peak area against the standard was +0.9995 +/- 0.0003 for samples in the 300-3000-microgram range.