Sequential Potentiometric Determination of Nitrate and Chloride in Vegetables

A rapid and simple sequential potentiometric method is described for the determination of nitrate and chloride ions in vegetables, by using home-made ion selective electrodes. The extraction of both ions from the vegetable samples was effected by magnetic stirring of the samples during 30 min in water at room temperature. Direct Potentiometry was used as analytical technique for measurement. The mean coefficient of variation, the average percentage of spike recovery and the detection limit for the nitrate determination in 17 samples of different vegetables were found to be 1.7 %, 100.5 % and 0.12 g Kg respectively. These values were found to be 2.3 %, 100.6 % and 0.08 g kg for the chloride ion. The mean nitrate and chloride ion concentrations determined by application of the proposed potentiometric method were found to be 7.18 g kg and 5.07 g kg, respectively. In addition Comparison of variances (F ) and linear regression analysis of the results obtained were carried out to validate the developed sequential potentiometric method.