Comparing efficiency of different methods for measurement of nitrate and nitrite in foodstuf

Abstract

Introduction: Nitrate and nitrite are chemicals found as a preservatives in foods also due to increased agricultural use of fertilizers, vegetables may contain higher level of nitrate, An excess amount of them in food may have harmful health effects. Objective: This study compared efficiency of our proposed method with three different methods for determination of nitrate and nitrite in some foodstuff such as sausage, potatoes and onions. Methods: In order to compare the efficiency of these methods, different amounts of nitrate and nitrite were spiked to the samples. And then the amount of nitrate and nitrite, recovery values and other validation parameters such as limit of detection, limit of quantification , and relative standard deviation % were determined and compared. Results: The obtained results indicated that under the optimal conditions, the proposed method was linear in the concentration range of 35 to 50000 ng/ml (R2=0.9997) with a LOD of 9.1 ng/ml, and the method was accurate 0.3%- 3.2% and precision parameter 1.6% -2.5%. for ISO 6635 method, the linearity range is 0.5-3 µg/ml (R2=0.9966), LOD was 220 ng/ml (nitrite), RE% was 0.85%- 9.6% and precision parameter was 2% -7.8%. and for nanoparticles preconcentration method, LOD was 1.68 ng/ml, RE% was 0.6-2.7 and precision parameter was 1.27-3.5%. Conclusions: By taking the obtained results into the consideration it can be said that the proposed method can be used for determination of nitrate in some vegetables. The ISO 6635 method can be used as a convenient method for measuring nitrite due to its simplicity and accurate repeatability for nitrite measurement.