FIELD: food industry. SUBSTANCE: method involves determining ammonium ion -NH+
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concentration C1 in milk sample and interpreting the obtained results in terms of milk quality. Ammonium ion -NH+
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concentration C1 in milk is determined by clarifying the milk sample and making photometric examination. To clarify milk sample, compounds are added which reference electrode reduction potential in alkaline medium is greater than 0.9 V. Metal hypochlorates and/or metal peroxides are optionally added to the milk sample for clarifying the sample. To carry out photometric examination, colored compound of ammonium ions with phenol and/or substituted phenol and/or Naphtol and/or Polyphenol and/or Polynaphtol is produced. To produce the colored compound of ammonium ions with phenol, water, sodium-potassium tartrate, caustic soda, phenol and sodium hypochlorate solutions are added to the milk sample in consecutive order. Electromagnetic radiation of 620-640 nm wavelength is applied for performing photometric examination. Ammonium concentration deviation from permissible reference value is interpreted in terms of milk quality by determining ammonium ions concentration C0 in control sample and obtaining more accurate value of milk quality from the calculated difference C1-C0. To draw conclusions concerning milk quality, nitrogen, protein and gelatin contents are determined. EFFECT: high accuracy and sensitivity in determining nitrogen and ammonium presence. 13 cl
