Optimized UHPLC-derivatization method for low-level nitrite detection in pharmaceutical excipients

This work presents a method optimization strategy for determining nitrite ions in pharmaceutical excipients. After derivatization, nitrite ions were analyzed using ultra-high-pressure liquid chromatography with UV detection. The article details how to achieve a sensitivity of 1 ng/mL (0.1 ppm) in pharmaceutical excipients while maintaining an analysis time of less than one minute. The results of nitrite measurements in several excipients obtained using the limit test to validate the analytical method are presented. The article also explains how to further reduce the detection limit while maintaining the analysis time. The advantage of the presented method is that it offers simple sample preparation and reproducible recovery above 90%. The article also shows what problems can be caused by incorrect sample preparation and excipient storage.