A simple, precise, accurate, high reproducible and economical visible spectrophotometric method of analysis for the determination of thiamine was developed and validated. The proposed method involves
diazotization of sulphanilic acid under acidic conditions in presence of sodium nitrite, followed by its coupling with thamine in alkaline medium. The absorption spectra of the yellow colored formed between thiamine and positive diazonium ion has absorption maximum at 405 nm. The linear regression analysis data for the calibration plot showed good linear relationship (r = 0.9969) with in the concentration range of
(2 –26)μg mL-1. With molar absorption1.0253×104 L.mol-1.cm-1. The
method was successfully applied in the evaluation of thymine in pharmaceutical preparation