DEVELOPMENT OF HPLC METHOD FOR ANALYSIS OF NITRITE AND NITRATE IN VEGETABLE

Abstract

The presence of nitrates and nitrites in food is associated with an increased risk of gastrointestinal cancer and, in infants, methemoglobinemia. Approximately 80% of dietary nitrates are derived from vegetable consumption; sources of nitrites include vegetables, fruit, and processed meats. Nitrate may be reduced into cancerogenic nitrite under various condition. In this work development of a simple HPLC method for simultaneous analysis of nitrite and nitrate was performed. The retention of nitrate and nitrite on the sorbent RP-18 endcapped was studied under the conditions of ion-pair high-performance liquid chromatography, depending on the concentration of organic solvent (methanol) in the mobile phase, pH of the phosphate buffer solution and flow of mobile phase. The optimum conditions were selected for the separation of nitrite and nitrate in the isocratic elution mode within 15 min. A procedure was developed for their determination in vegetable; the detection limit was 50 mg/L for nitrite and 25 mg/L for nitrate. The method is relatively simple, sensitive, selective and can be applied to the monitoring of nitrite and nitrate in vegetable products.