Spectrodensitometric determination of chloramine-T in ice cream

A spectrodensitometric method has been developed for the quantitative determination of chloramine-T (N-chloro-N-sodium-p-toluenesulfonamide) in ice cream. Chloramine-T is extracted and converted into p-toluenesulfonamide (p-TSA) followed by thin layer chromatographic separation of concentrated extracts on silica gel and quantitation of the p-TSA spots from standards and samples by direct scanning with a reflectance densitometer at 228 nm. A linear relationship was obtained between recorded peak area and concentration for 0.5--7.0 microgram p-TSA/spot. The reproducibility of the complete method was 2.87% (n = 9 determinations). The detection limit of the scanning procedure was 0.5 microgram p-TSA/spot, corresponding to a concentration of 4 mg chloramine-T/kg sample. The average recovery was 88 +/- 3% (P = 95%) for 10 ice cream samples spiked with chloramine-T at levels ranging from 10 to 55 mg/kg. The described method was used to assay 146 commercial ice cream and whipped cream samples for chloramine-T.