SIMULTANEOUS DETERMINATION OF NITRITE, NITRATE AND ASCORBIC-ACID IN CANNED VEGETABLE JUICES BY REVERSE-PHASE ION-INTERACTION HPLC

A simple ion-interaction C-18, reverse-phase high performance liquid c hromatographic method was developed for simultaneous determination of nitrite, nitrate and ascorbic acid in canned vegetable juices. The met hod makes use of 0.010 M octylammonium orthophosphate as the ion inter acting reagent and 20% (v/v) aqueous methanol as the mobile phase. The content of nitrite, nitrate (expressed as nitrite ion and nitrate ion , respectively) and ascorbic acid in commercial brands of canned tomat o, carrot and mixed vegetable juices were surveyed. The quantitative r esults indicated that, nitrite was very probably added as a preservati ve in the canned vegetable juices. The total amount of nitrite and nit rate ion per can in two commercial brands of vegetable juices was foun d to exceed the acceptable daily intake recommended by the 1996 Joint FAO/WHO Expert Committee on Food Additives for an average adult of 60 kg body weight.