Spectrophotometric determination of sulphite and thiamin hydrochloride via Xylenol orange dye

a simple, acurate and rapid spectrophotometric method for determination of sulphite thiamine hydrochloride (B1) is described. This used proton transfer reaction between ion with xylenol orange at pH(7.6) to develop red colour adduct that maximum absorption 580 nm. was by bleaching the product (xylenol orange-sulphite) optimum conditions established sulphite. Beer’s law obeyed in concentration range (10-1000) μg/25ml (i.e. 0.4-40) 10-2000, 0.4-80) selected wavelength, molar absorbtivity 2.8×104 l.mol-1.cm-1 SO32- 2.69×104 hydrochloride, Sandell's index sensitivity 0.002857 μg .cm-2 0.012537 B1. Good recoveries from water samples pharmaceutical formations are achieved using proposed method.