Ion exchange chromatography can separate both nitrate and nitrite among anions using anion exchange column

the method is described in this standard test method (ASTM D4327 https://www.astm.org/d4327-17.html)

Dear Srikant,

Looking the limits for Nitrite and Nitrate the best technique is suitable is Ion exchange chromatography where both nitrate and nitrite can be quantified with LOD & LOQ at lowest level. By using derivatization technique you may use HPLC but the system itself is very costly where as Ion chromatography is suitable technique with regulatory acceptance. Recently I have worked for USFDA query for excipient.

Hopefully this answer will suffice your requirement

Hello, nitrate and nitrite best analysis are by ion chromatography with an anion suppression system.

Dear Srikanth Voruganti

We know ion-pair separations on conventional reversed-phase material with UV detection. Tetrabutylammonium-hydrogen sulfate is commonly used as the ion pair reagent in the low double-digit mmol/L range with ACN as the organic modifier, and UV detection is applied at 210 nm. Depending on the matrix, this may be a suitable approach, or it may not. Our colleagues have suggested ion chromatography as the preferred method since it has the lowest matrix influence. In most cases, suppressed conductivity is sufficient. However, there are cases with high chloride concentrations that require a combination of suppressed conductivity for most ions and UV detection for nitrite and nitrate. To provide better advice, please let us know the matrix information and the concentration levels you require. Cheers, Detlef.

Thank you Jenson . I have tried acclaim Trinity P1 column for nitrites determination by HPLC. Mobile phase 60mM ammonium bicarbonate with pH 6.5 and 214nm. 100 ppb concentration is needed and I am getting bad recoverieS.

%RSD for STD is good. Can anyone advise me to solve the issue.

Dear Srikanth Voruganti

Your question is difficult to answer without a detailed description of your sample matrix (e.g., fluoride, chloride, carbonate, phosphate, and sulfate concentration, to name the obvious non-chromophoric anions). As always has the matrix a big say in the determination, as you observe. In addition, what is a bad recovery, and for what anion? Nitrite, nitrate, or both? If your samples contain N-metabolizing bacteria, the effect might differ from the conventionally known autooxidation of nitrite to nitrate.

If it is the autooxidation of nitrite to nitrate in water samples, a relatively new and surprisingly simple stabilization method might help. Researchers from Ireland published a paper showing that adding low single-digit mmol/L thiourea helped stabilize nitrite in drinking water.

And from my point of view, a good old ion exchange column (e.g., IonPac AS14a) with an aqueous NaCl-eluent (30 mmol/L) works wonders with many environmental samples.

But - this is all guesswork w/o proper sample details.

In all fairness, please provide the community with the essential information we need to help you.

Kind regards

Detlef Jensen.