Capillary gas chromatographic determination of naphthalene in bran and wheat germ products

A method is described for determining naphthalene in bran and wheat germ products. The method involves distilling the naphthalene from a water-cereal mixture and then extracting the distillate with hexane. A 10 microL aliquot of the hexane extract is injected into a gas chromatograph equipped with a capillary column. Dodecan-1-ol is used as the internal standard. Mean recoveries, standard deviations (SD), and coefficients of variation (CV) for samples of unprocessed bran, unprocessed wheat germ, bran flakes breakfast cereal, and sultana bran breakfast cereal, spiked with naphthalene at various levels, were 1.0 ppm spike, mean 0.98, SD 0.09, CV 9.5%; 2.5 ppm spike, mean 2.37, SD 0.22, CV 9.4%; 5.0 ppm spike, mean 4.86, SD 0.19, CV 4.0%; 10 ppm spike, mean 9.25, SD 0.38, CV 4.1%. The mean recoveries exceeded 90% in each case. The detection limit for the method was about 0.5 ppm.