Gas-Liquid Chromatographic Determination of N-Nitrosodimethylamine in Ham
Abstract A method is described for the gas chromatographic determination of N-nitrosodimethylamine in ham. The use of a commercial rubidium sulfate alkali flame ionization detector for nitrogen-containing compounds permits a simple cleanup procedure and a rapid analysis. This method consists of digesting the ham sample with methanolic KOH, distillation from aqueous alkali, washing the distillate with hexane, acidification and extraction of the aqueous layer with methylene chloride, and washing the extracts with base prior to concentration. The sensitivity of the method is 25 ppb; the average recoveries at this level range from 73 to 100%. Ten hams including 4 varieties were analyzed and found to contain less than 1 ppb apparent N-nitrosodimethylamine.