Determination of niacin in fresh and dry cured pork products by ion chromatography: experimental design approach for the optimisation of nicotinic acid separation

Abstract A simple and robust method to determine the niacin level in fresh and dry-cured pork products by ion chromatography is reported. The analytical procedure includes an acidic hydrolysis to free all the bound forms (NAD and NADP) and to convert all the niacin into nicotinic acid, after that the chromatographic separation of the acid form is performed by a cation-exchange column and UV detection (262 nm). The evidence of several interferences that did not allow a good resolution of the nicotinic acid peak in fresh meat matrix led us to improve the resolution by means of statistical optimisation. A three level factorial design and response surface methodology were applied to optimise the chromatographic conditions (mobile phases compositions) and to assess the robustness of the method. Analytical performances of the optimised method were investigated in terms of linearity, limit of detection (LOD) and precision. The complete analytical procedure to extract and determine the nicotinic acid in meat was validated by IC-MS.