Determination of Nitrates, Nitrites and Oxalates in Kale and Sultana Pea by Capillary Electrophoresis

Abstract

The objectives of this research were to determine the quantities of nitrate, nitrite and oxalate in two vegetables those are popular at Black Sea coast namely kale and sultana pea. The results were compared with the contents of spinach and chard. Simultaneous determination of nitrate, nitrite and oxalate was conducted with capillary electrophoresis by using an acidic run buffer to reverse the electroosmotic flow. Full factorial design with three variables was applied to decide the optimum capillary electrophoretic experimental conditions. The limit of detection was improved by large volume sample stacking. The average amount of nitrate in fresh kale leaves (2016 +/- 519 mg kg(-1)) was greater than spinach and lower than chard. The nitrite ion concentrations were much more in the leaves of kale (111 +/- 4 mg kg(-1)) than in stalks on the contrary of chard. Oxalate content was lower in kale (2970 +/- 672 mg kg(-1) than in spinach and chard.