Thermo Fisher Scientific has announced an application for the determination of nitrite and nitrate in milk by ion chromatography (IC) with suppressed conductivity detection using inline sample preparation.
Excessive consumption of nitrite and nitrate has been implicated as a cause in some health problems. As a result, the United States Environmental Protection Agency (US EPA) has regulated the amount of nitrite and nitrate in drinking water. These same limits should be applied to milk even though the FDA and USDA have not required testing of milk for nitrate and nitrate.
Application Note 279 ‘Time Savings and Improved Reproducibility of Nitrate and Nitrite Ion Chromatography Determination in Milk Samples’ demonstrates this testing method using a simple acid precipitation followed by additional inline automated sample preparation prior to chromatography. The prepared sample is separated on the Thermo Scientific Dionex IonPac AS20 hydroxide-selective anion-exchange column to resolve nitrite and nitrate from the remaining sample components. The Dionex Reagent-Free IC (RFIC) system automatically prepares the separation eluent to achieve high separation reproducibility. The automated sample and eluent preparation saves time and improves the reproducibility of the analysis.