Gas chromatographic determination of nitrite in foods as trimethylsilyl derivative of 1H-benzotriazole.
1,2-Diaminobenzene reacts with nitrite in acidic solution to form 1H-benzotriazole, which can be extracted into ethyl acetate. After evaporation of the ethyl acetate, 1H-benzotriazole is determined as its trimethylsilyl derivative by gas--liquid chromatography on a column of 15% SE-30 on chromosorb G HP at 200 degrees C with flame-ionization detection. The nitrite concentration is calculated from the peak height. Amounts of 0.5--10 microgram of nitrite-nitrogen can be determined. For the determintion of nitrite in foods, clean-up of the crude extracts by ion-exchange column chromatography allows the satisfactory elimination of interferents and permits concentrations down to 0.41 ppm to be determined. The recovery of the nitrite added to foods at the 4.1 ppm level ranges from 94.6 to 98.7% and at the 8.2 ppm level it ranges from 95.2 to 98.8%. The trimethylsilyl derivative of 1H-benzotriazole was identified as 1-trimethylsilylbenzotriazole by combined gas chromatographic--mass spectrometric examination and nuclear magnetic resonance spectrometry.
D005504:Food Analysis / Q000379:methods; D005520:Food Preservatives; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D008452:Maximum Allowable Concentration; D009573:Nitrites / Q000032:analysis* / Q000633:toxicity
D005520:Food Preservatives; D009573:Nitrites