EXPRESS METHOD FOR ESTABLISHING MILK FALSIFICATION BY DILUTING IT WITH WATER ACCORDING TO PIEZOSENSORS ARRAY SIGNALS Russian patent published in 2017 - IPC G01N33/04 G01N27/12 

FIELD: chemistry.

SUBSTANCE: method provides the use of an "electronic nose"-type detection device, the matrix of which is formed on the basis of four resonance-type piezosensors. A film weighing 10-15 g of a particular sorbent: rhodamine 6G (Rhod6G) polyethyleneglycoladipinate (PEGA), dicyclohexano 18 Crown-6N (18-K-6), bee glue (PchK) - is applied on defatted electrodes of the piezosensors with the oscillation frequency of 10.08 MHz. The piezosensors are maintained until a stable oscillation frequency is established, and then samples are taken, and the samples are placed in sealed glass vessels with a soft polymer membrane and incubated for 10-15 minutes at a temperature of 18-22°C. By means of a disposable syringe 2 cm³ of the equilibrium gas phase is selected and introduced into a static cell of the detecting device, the piezosensors responses are recorded for 60 seconds, the highest analytical signal ΔFc is selected, the ratio of signals and is calculated, where Δ_FRhod6G is an analytical signal of a piezosensor with Rhod6G sorbent; Δ_F18-K-6 is an analytical signal of a piezosensor with 18-K-6 sorbent; Δ_FPEHA is an analytical signal of a piezosensor with PEHA sorbent; Δ_FPchKis an analytical signal of a piezosensor with PchK sorbent, and compared with those of a standard sample; wherein the simultaneous increasing the ratio of signals compared to the standard by more than 30% and decreasing the ratio of signals by more than 10% characterizes excessive water content in the milk, that indicates the milk falsification by diluting it with water.

EFFECT: high rapidity, accuracy, objectivity of the measurement and reliability of determining the fact of falsifying the milk by water.

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