High pressure liquid chromatographic determination of chloramine-T in food.

A high pressure liquid chromatographic (HPLC) method for determining chloramine-T (N-chloro-N-sodium-p-toluenesulfonadmie) in foods such as ice cream, minced meat, and shrimp is described. Deproteinized samples are treated with sulfite to convert chloramine-T to p-toluenesulfonamide (p-TSA) and extracted, and HPLC analysis is performed on concentrated extracts. Sample extracts are chromatographed on a reverse phase 10 micrometers Lichrosorb RP-18 column with acetonitrile-water (190), and quantitated by an ultraviolet detector (220 nm) and digital integrator. The relationship between recorded peak area and concentration was linear to 0.600 micrograms p-TSA/microL. The detection limit was 2.5 ng pTSA/microL, corresponding to a chloramine-T concentration of 0.8 mg/kg in samples. Recoveries of added chloramine-T were 88% for ice cream, 73% for minced meat, and 51% for shrimp. Precision data indicate a relative standard deviation of 1.54 and 2.14% for the complete analysis of ice cream with levels of 15 and 63 mg chloramine-T/kg (n = 5 determinations), respectively. The HPLC method was applied to chloramine-T determinations in 62 ice cream, 25 minced meat, and 25 shrimp samples.