Determination of p-toluenesulfonamide in ice cream by combination of continuous flow and liquid chromatography: summary of collaborative study.

A collaborative study of the determination of p-toluenesulfonamide (p-TSA) in ice cream by a combination of continuous flow and on-line liquid chromatography was conducted. Seven ice cream samples containing 0-6.35 mg p-TSA/kg at 4 levels (1 blank and 3 pairs of split level samples) were analyzed by 11 laboratories. For all samples analyzed, the repeatability relative standard deviation varied from 2.08 to 3.67%, whereas the reproducibility relative standard deviation ranged from 7.79 to 11.68%. The average p-TSA values for the split levels 1, 2, and 3 were 0.55, 1.02, and 4.44 mg p-TSA/kg, respectively, with mean recoveries ranging from 76 to 79% (overall recovery range for all levels, 63-101%). No false positive results were reported for the blank sample, and no interference was encountered by the presence of vanillin in samples. The method has been adopted first action by AOAC INTERNATIONAL. 993.22 p-Toluenesulfonamide Residues in Ice Cream-Combined Continuous Flow and Liquid Chromatographic Method.