Computer program for the determination of salicylic acid content in aspirin by derivative spectrometry

A mathematical program in Turbo Pascal 6.00, which is enable to generate spectra and to obtain first and second order derivative spectra, is proposed. The second order derivative spectrum of salicylic acid showed a trough at 292 nm and a satellite peak at 316 nm. When large amounts of aspirin coexisted, the trough disappeared, but the height of satellite peak (D) was not altered even at an aspirin concentration which was 2000 times more than that of salicylic acid (corresponding to salicylic acid content of 0.05%). The results were compared with those obtained by using a spectrophotometer for recording the second order derivative spectrum of aspirin.