The invention provides a method for detecting a
potassium salt in
cow milk. The method comprises the following steps of mixing 19.45mL of a
disodium hydrogen phosphate solution with a concentration of 0.2mol / L, 0.55mL of a
citric acid solution with a concentration of 0.1mol / L and 1.32g of
sodium tetraphenylborate, dissolving the mixture by
distilled water to obtain 100mL of a
sodium tetraphenylborate buffer, taking 5mL of
cow milk to be detected, dropwisely adding an acid solution into the
cow milk, carrying out mixing to obtain a uniform solution, carrying out
centrifugation after condensation, collecting the supernatant A, taking 0.5mL of the supernatant A, adding 0.7mL of the
sodium tetraphenylborate buffer into the supernatant A, carrying out mixing to obtain a uniform mixture, carrying out
centrifugation, collecting the supernatant B, taking 1mL of the supernatant B, adding 0.3mL of the
sodium tetraphenylborate buffer into the supernatant B, carrying out mixing to obtain a uniform
mixed solution, carrying out observation, wherein if the
mixed solution is clear and transparent, the tested cow milk does not contain the
potassium salt, and if the
mixed solution produces a lot of white precipitates, the tested cow milk contains the
potassium salt. The method can be operated simply and has a low detection cost.