Detection for the conversion of nitrate into nitrite - uses 1,3-phenylene di-amine in a biological sample, useful in the food and sanitary industry

摘要

In the detection method, a biological sample is grown in the presence of 0.01-10 g/l. 1,3-phenylene diamine (1,3 PD) or its salts at a temp. of 1-70 deg.C for up to 14 days and its absorbence is then determined photometrically or by visual examination. The sample may already contain nitrates or they may be added with the growth medium. Pref. the pH is optimal and the growth is in the presence of nutrients and/or microbial growth factors e.g. amino acids and peptone. 1,3-PD does not significantly inhibit microorganisms or their enzymes. The nitrites formed bind to 1,3-PD creating an easily identifiable light-absorbent component. The absorbence can be measured at 450 nm. USE/ADVANTAGE - The determn. of nitrites which are hazardous to health is essential in the food industry or in the health sector. Selective growth media for the detection of nitrite producing bacteria can be produced. The invention can be used in microbial and enzyme tests for the determn. of a nitrate content. In contrast to the present method, current methods use reagents which influence the nitrite formation. Additionally, they are more expensive and cumbersome.