DEVELOPMENT THE METHOD OF DETERMINATION OF CATIONS LYSINE AND THIAMINE IN THE RECONSTITUTED MILK WITH USING PD-SENSORS
The sensitivity and stability of the response of the PD-sensors based on membranes MF-4SC in K-, H-, Lys-forms in solutions of the reconstituted milk were investigated. A multisensory systems with PD sensors and ion-selective electrodes for the recognition of reconstituted milk containing powdered milk from 0.40 to 8.46 mas. % is developed. The sensitivity of PD-sensors to cations of lysine in the test solutions containing 0.40 wt. % of powdered milk and 1.0·10 <sup>-3</sup>-1.0·10 <sup>-1 M of LysHCl was 29 mV/</sup>pC for membranes in the K-type. The sensitivity of PD-sensors to cations of thiamine in the test solutions containing from 0.40-3.40 wt. % of powdered milk and 1.0·10 <sup>-4</sup>-1.0·10 <sup>-1 M of ThiaminCl was from 18 to 12 mV/</sup>pC for membranes in the K-type. This sensitivity is sufficient for the quantitative determination of cations of lysine and of thiamine in solutions of reconstituted milk. The limit of detection of cations of lysine and thiamine in reconstituted milk was 4.0·10 <sup>-6 М</sup> and 2.9·10 <sup>-6 М</sup> respectively. The relative error of measurement was not more 10 %.