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 14min. Since it requires only 2–7mg 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 in connection with the gas chromatograph employing dual flame-ionization detectors. The average recovery of salicylic acid in synthetic samples containing 400–2700μg 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-μg range.