Nitrate and nitrite salts are often used as food additives in processed meats like bacon, ham, sausages, etc. to stabilize the color of red meat. They also function as preservatives, helping to prevent the growth of microorganisms that cause food poisoning. The presence of nitrite/nitrate in processed meat is believed to increase the risk of cancer in the digestive tract. For these reasons, use of nitrate and nitrite salts as food additives is strictly regulated worldwide. For example, the European Commission established the maximum allowable concentration for nitrate and nitrite salts in processed meat as 150 mg/Kg. Nitrate and nitrite are also found naturally in vegetables and fruits. Most vegetables usually have low levels of nitrate, with leafy vegetables such as lettuce, spinach, arugula etc. having the highest levels. Conversely, only trace amounts of nitrite (&lt;10 mg/kg) are present in vegetables. <br/>Ion chromatography (IC) is a well-established technique for the analytical determination of nitrite and nitrate. In this work, we developed an IC method using a high capacity version of the Dionex™ IonPac™ AS11 column to separate nitrite and nitrate from other anions present in a meat homogenate and slurried spinach. The Dionex IonPac AS11-HC column is a high capacity column, which allows relatively large injection volumes, thus facilitating the determination of low nitrate and nitrite concentrations. Nitrate and nitrite were separated on a 2 × 250 mm IonPac AS11-HC column at a 0.38 mL/min flow rate using potassium hydroxide (KOH) eluent produced by the Dionex™ EGC 500 KOH Eluent Generator Cartridge. After the separation, nitrate and nitrite were detected by suppressed conductivity detection.<br/>The two food samples were extracted with deionized water and subjected to a series of simple clean up steps before they were injected into the IC system. The method showed good precision with RSDs &lt;0.2%, and &lt;5% (n=9), for retention time and peak area respectively. The recoveries from meat homogenate and slurried spinach sample ranged from 89-100%. The limit of detection (LOD) and the limit of quantitation (LOQ) were 2.26 ppb and 7.52 ppb for nitrate and 1.33 ppb and 4.42 ppb for nitrite respectively.<br/>

Simultaneous determination of nitrate and nitrite in spinach and meat by ion chromatography

ACS Fall 2020 Virtual Meeting

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