METHOD FOR DETERMINING UREASE ACTIVITY OF SOILS USING POLYURETHANE FOAM TEST AGENTS Russian patent published in 2024 - IPC G01N21/49 

FIELD: biotechnology.

SUBSTANCE: determination of urease activity is carried out using polyurethane foam test agents and subsequent digitization of results using various programs and applications, which enable to determine the change in colour intensity of the test agent. Sample of soil containing bacteria having urease activity is placed in a test tube and a fixed amount of urea is added, 10–15 minutes later, a polyurethane test agent impregnated with an aqueous solution of sodium para-aminosulphosalcylate/chloramine in ratio of 1:1 is placed in a test tube at distance of 2–5 cm. Urease activity is determined by urea hydrolysis reaction with urease enzyme, i.e. quantitatively based on released ammonia, which stains test agents in red-brown colour. Colour intensity is directly proportional to the concentration of ammonia recovered from the sample, and therefore to urease activity.

EFFECT: use of the invention makes it possible to analyse soil with determination of urease activity from 0,50 to 300 mg of ammonia/kg of soil; test means can be regenerated and reused in analysis.

1 cl, 1 tbl, 9 ex