SEQUENTIAL POTENTIOMETRIC DETERMINATION OF CHLORIDE AND NITRATE IN MEAT-PRODUCTS

The analytical control of chloride and nitrate in meat products is imp ortant. For this reason in this work a sequential method for their det ermination by using chloride- and nitrate-selective electrodes has bee n developed. The extraction of both ions was carried out by stirring t he samples for 30 min in a hot 50 x 10(-2) mol litre(-1) sulphuric aci d solution. Direct potentiometry for chloride and multiple standard ad ditions for nitrate were used as analytical techniques of measurement. The mean coefficient of variation and the average percentage of spike recoveries calculated for the chloride determination in five differen t meat products were 0.68% and 101%, respectively. For the nitrate det ermination these data were 0.84% and 101%, respectively. The limits of detection were 71.0 mg kg(-1) and 23.2 mg kg(-1) for chloride and nit rate, respectively. The mean chloride and nitrate concentrations deter mined by application of the developed method to 50 samples of meat pro ducts were found to be 21.1 g kg(-1) and 133.5 mg kg(-1), respectively . Throughout the study, the Volhard titration for determination of chl oride and the brucine spectrophotometric method for determination of n itrate, adopted as reference methods, were used simultaneously. Compar ison of variances and linear regression analysis of the results obtain ed were carried out to validate the proposed sequential potentiometric method. (C) 1997 Elsevier Science Ltd.