“…Free salicylic acid has been determined by column chromatography (1)(2)(3) and direct UV spectrophotometry (4,5). Aspirin has been determined using spectrophotometry (13-15), GLC (16), NMR spectroscopy (17), nonaqueous titrimetry (18-20), TLC (21)(22)(23), and HPLC (24,25). Aspirin has been determined using spectrophotometry (13-15), GLC (16), NMR spectroscopy (17), nonaqueous titrimetry (18-20), TLC (21)(22)(23), and HPLC (24,25).…”