Direct Potentiometric Measurement of Nitrate in Seeds and Produce

A highly stable and selective nitrate sensor was utilized for the development of a new methodology for the direct determination of nitrate concentration in dried greens and seeds. The method developed allows for the accurate (100–102% recovery values in lettuce, olive leaves and coffee beans) and fast (4 to 8 minutes) analysis of the samples without the need for filtration or other sample preparation steps. The coefficient of variation (CV) of the proposed method is below 5% for all samples analyzed.