Liquid chromatographic determination of total niacin in beef, semolina, and cottage cheese.

A sensitive and precise liquid chromatographic method has been developed for the determination of total niacin in beef, semolina, and cottage cheese. The samples are extracted with Ca(OH)2, cleaned up using C18 Sep-Pak cartridges, and chromatographed on a C18 column using a mobile phase consisting of 23% acetonitrile, 0.10% H3PO4, and 0.10% sodium dodecyl sulfate in water. Niacin is detected using an absorbance detector operating at 254 nm. This chromatographic system produces an unusually sharp peak for niacin, enabling a detection limit of approximately 0.05 mg/100 g. The mean recovery was 99.5% and the coefficients of variation for beef, semolina, and cottage cheese were 3.58, 1.02, and 10.0%, respectively.