Samples were pretreated by ultrasonic extraction, and de-colorizing through active carbon column, and filtering through microporous membrane. The determination of nitrate and nitrite in vegetables was carried out with ion chromatograph. The varieties of nitrate and nitrite content in 4 kinds of vegetables in different storage conditions were analyzed. The results showed that nitrate content decreased basically and that nitrite content was kept stable after increasing significantly in 4 kinds of vegetables kept in room or cooled temperature for 7 days , but nitrite content in vegetables stored ...
