OPTIMIZATION OF THE PARAMETERS OF THE STAND FOR PHOTOLUMINESCENT DIAGNOSTICS OF MILK CONTAMINATED WITH ANTIBIOTICS

To obtain high-quality milk, its analysis is systematically carried out on dairy farms, this information is used in production management, disease diagnosis and adjustment of animal feeding diets. Technical solutions of express milk analyzers work as measuring instruments that allow obtaining actual data on each sample by collecting information through sensors. Milk analysis devices based on optical methods (surface plasmon resonance, colorimetry, fluorescence, Raman spectroscopy and others) are used. A method of photoluminescent analysis of milk using light and photodiodes has been developed. (Research purpose) The research purpose is optimization of the location of the radiation source and receiver, as well as the time parameters of the stand for photoluminescent diagnostics of milk. (Materials and methods) It was shown that the test bench includes eight LEDs and four photodiodes in a light-tight enclosure. The milk of the Michurino agrofirm, having a fat content of 2.5 percent, was used as an object of measurement; the sample volume corresponded to the cuvette volume of 13-15 milliliters. (Results and discussion) In order to optimize the operation of the laboratory stand, its adjustment was carried out, including adjusting the height of radiation sources and receivers relative to the measured object, selecting the pulse duration of the LED to excite the milk under study, selecting the turn-on delay of the photodiode to register the luminescence of milk. Optimization criteria were: the minimum dark signal, the minimum error in determining the radiation flux, and the minimum measurement time. (Conclusions) It was determined that the optimal distance between radiation sources, receivers and measured objects is 4.5 centimeters for LEDs and 2.3 centimeters for photodiodes. It was found that the optimal pulse duration is 19 microseconds, thanks to which it was possible to minimize the parasitic dark signal. It was found that the optimal delay before switching on the photodiode is 1 microsecond.