Determination of S-carboxymethyl-L-cysteine, methylparaben and their degradation products in syrup preparations

Abstract

An HPLC method was developed for the determination of S-carboxymethyl-L-cysteine, methylparaben and related compounds in cough syrup preparations. The HPLC operating conditions used were acetonitrile-methanol-water (120:280:600, V/V/V) pH adjusted to 4.0 with 0.1 M HC1, on a 5um Spherisorb ODS2 column (250 mm x 4.6 mm) with a flow rate of 1 mL min(-1) injection volume was 10 muL and absorbance was monitored at 210 nm with 0.05 a.u.f.s. sensitivity.