Simultaneous determination of nicotinic acid and nicotinamide in cooked sausages

A simple and sensitive method for determining simultaneously nicotinic acid and nicotinamide content in cooked sausages by ion-pair reversed-phase liquid chromatography is described. Samples are extracted with ultrapure water, centrifuged, deproteinized with zinc hydroxide, filtered, and chromatographed with UV detection at 261 nm on a 25 cm x 4 mm i.d. Spherisorb ODS-2 cartridge using as mobile phase a mixture consisting of 5 mM heptanesulfonic acid adjusted to pH 3.3 with phosphoric acid and acetonitrile (75:25, v/v). Both vitamins are measured on a reversed-phase column with a single ion-pair reagent. Precision of the method was 0.5 and 1.0% (within a day) and 2.3 and 4.5% (between days) for nicotinic acid and nicotinamide, respectively. The detection limit was 0.300 mg/100 g. The recovery was >92% of nicotinic acid and nicotinamide added to samples of meats. Twenty samples of six different products have been analyzed in duplicate. The mean value for nicotinic acid ranged between 0.908 and 1.267 mg/100 g of fresh weight and for nicotinamide between 1.968 and 2.880 mg/100 g of fresh weight.