1976 Volume 17 Issue 6 Pages 428-433_1
A improved method for determination of nitrite in foods was established. Sample was finely comminuted and thoroughly mixed, then 5-10g of the mixture was transferred into a 500ml volumetric flask and added 300ml of distilled water and heated to 80°C on a steam bath for 2hr with occasional shaking. The flask was cooled to room temperature and the volume was made to 500ml with distilled water. After the solution was shaken, it was filtered. Then, 200ml of the filtrate was transferred to a column of Dowex I-X4 (Cl form) of 8cm length. The nitrite on the column was eluted with 25ml of 25% sodium chloride solution. The effluent was adjusted to pH 1.5, and transferred to 50ml Erlenmyer flask, and added 0.5ml of 0.2% o-phenylenediamine solution. After the mixture was stirred for 10 seconds, it was heated to 80°C on a steam bath for 5min. The flask was cooled to room temperature, the reaction mixture was transferred to a 50ml beaker, and adjusted to pH 2.5 with 2% sodium hydroxide solution. The prepared solution was transferred to a 50ml separatory funnel, and added 5g of sodium chloride and 10ml of butyl acetate. Then, 1H-benzotriazol was extracted with butyl acetate and nitrite was determined by gas chromatography as 1H-benzotriazol.
Under the condition described above, it was found that the nitrite in a few kind of foods could be determined with recovery of 97-103% and variation coefficient of about 9%.
