Abstract:

A new method based on the combination of on-line dialysis and ion chromatography was established for measuring nitrite and nitrate in cooked meat. Samples were suspended in water, extracted in ultrasonic bath and centrifuged. The resulted supernatant was then subjected to on-line treatment with dialysis before being injected into Ag column. Nitrite and nitrate were separated on a Metrosep A Supp 4 anion exchange column using an eluent composed of a mixed aqueous solution of 1.8 mmol/L Na2CO3 and 1.7 mmol/L NaHCO3 and monitored using suppressed conductivity detector. The limits of detection of this method for nitrite and nitrate were 0.004 mg/L and 0.005 mg/L, respectively. The average recoveries were in the range of 88%－105%. This method presents the benefits of rapidity, high sensitivity and precision and easy performance, thereby providing a promising approach for simultaneous determination of nitrite and nitrate in cooked meat.

Key words: ion chromatography, dialysis, cooked meat, nitrite, nitrate