Methods Enzymol. 2005;396:61-8.

Qualitative and quantitative determination of nitrite and nitrate with ion chromatography.

Abstract: Reactions of nitrogen monoxide and peroxynitrite often yield nitrite and nitrate as stable end products. The simultaneous detection of these two ions by anion chromatography with conductivity detection is described. The chromatographic system used is similar to conventional isocratic or gradient high-performance liquid chromatography equipment. The columns are packed with ion-exchanging resins instead of silica-derived adsorbents. Conductivity, though inherently nonspecific, has the advantage of covering a linear dynamic signal range of five orders of magnitude, which is far better than spectroscopic techniques; these are generally limited to two orders of magnitude. Typical run times per chromatogram are 15-30 min, and sample and standard concentrations can be between 100 nM and 10 mM. Injection volumes vary from 5 to 200 microl. Unlike with the Griess method, which determines only nitrite, a true mass balance from independent signals can be obtained if nitrate and nitrite are the only products. DOI: 10.1016/S0076-6879(05)96006-0

J Chromatogr A. 1998 Apr 24;804(1-2):157-60.

Ion chromatographic determination of nitrate and nitrite in meat products.

Abstract: Nitrate and nitrite are usually added to processed meat products to provide protection against microorganisms that cause food poisoning. Nitrite may react with secondary amines to form nitrosoamines, a class of carcinogens. Nitrate, although it is more stable than nitrite, can act as a reservoir for nitrite. Thus, both nitrate and nitrite need to be monitored to ensure the quality and safety of meat products. In this paper, an accurate and sensitive method is described by which nitrate and nitrite are extracted from food samples, then analyzed by ion chromatography (IC). Commercial samples of ham and salami were analyzed by IC with UV absorbance detection. UV absorbance was specific for nitrate and nitrite, eliminating interference from other ions present at much higher concentrations. Recoveries of nitrate and nitrite were greater than 90%. The method was linear (r2 > 0.999) over the working range, and detection limits for nitrate and nitrite were 50 micrograms/l and 30 micrograms/l, respectively.

Griess methods is sensitive enough to quantify nitrite in these kind of samples (but they have to be previously decoloured).

Nitrate can be detected by UV after and acid digestion using HCl 1N-3N. These methods are described in the literature so far.

Best regards,

Rosa María Martínez-Espinosa

Check out applications from instrument manufacturers, like this one from Thermo.....

https://tools.thermofisher.com/content/sfs/brochures/AI-71449-IC-Beverages-Notebook-AI71449-EN.pdf