Aspirin--a national survey II: Determination of salicylic acid in bulk aspirin and aspirin formulations by high-pressure liquid chromatography using a fluorescence detector.

A quantitative high-pressure liquid chromatographic method, using a reversed-phase column coupled to a fluorescence detector, was developed to determine salicylic acid in bulk aspirin and plain and buffered aspirin tablets. The aspirin was dissolved, filtered, and injected into the chromatograph; the fluorescence of the salicylic acid was measured at approximately 425 nm. Excipients and impurities did not interfere, and recoveries of 100% were obtained. The method was used to analyze 84 aspirin samples.