VOLTAMMETRICAL METHOD FOR THE DETERMINATION OF DIPHENYLAMINE IN SHOT PRODUCTS Russian patent published in 2018 - IPC G01N27/48 

FIELD: chemistry.

SUBSTANCE: invention relates to the field of analytical chemistry, in particular to voltammetric analysis. Voltammetric method for the determination of diphenylamine in shot products on a glassy carbon electrode makes it possible to determine with high sensitivity the diphenylamine stabilizer of pyroxylin powders. Voltammetric method for the determination of diphenylamine in shot products, which includes the preparation of the analyzed sample by extraction of diphenylamine from the carrier object into the solution. According to the invention, the container is placed in a background electrolyte with 0.1 M NaC₄H₅O₆, after which the container is placed in the analyzer and indicator glassy carbon and saturated chloride-silver electrodes are immersed in it; further, the contents of the container is stirred and bubbled with an inert gas for 30 seconds, then a voltage is applied to the analyzer and the background electrolyte is electroaccumulated for 20 seconds at an electrolysis potential of -0.10 to 0.05 V, after the end of the electric accumulation of the background electrolyte, stirring and bubbling with an inert gas are terminated, and after 10 seconds the voltamgram is recorded in the potential range of 0.0–1.1 V at a potential sweep rate of 40–50 mV/s; at the same time, when the background is clean and there are no peaks in the 0.6–0.8 V region, 0.02–2.0 cm³ of the analyzed sample is added to the container with the background electrolyte and indicator glassy carbon and saturated silver chloride electrodes are placed in this container, then the contents of the container is stirred and bubbled with inert gas for 30 seconds; further, voltage is applied to the analyzer and the accumulation of diphenylamine is carried out for 20 seconds at an electrolysis potential of -0.10 to 0.05 V; then stirring and bubbling with an inert gas is terminated, and after 10 seconds a voltamgram is recorded in the potential range of 0.0–1.1 V at a potential sweep rate of 40–50 mV/s; further, a certified mixture of diphenylamine is added into the container with the background electrolyte and the sample to be analyzed, in such a volume, that the height of the peak of diphenylamine on the current-voltage curve increases twofold in comparison with the initial height of the peak, and the procedure for the electric accumulation of diphenylamine is repeated for 20 seconds at an electrolysis potential of -0.10 to 0.05 V, registering a characteristic peak of diphenylamine with an addition at 0.6–0.8 V. Invention makes it possible to quantitatively determine diphenylamine in shot products with a process error of up to 15 % and a range of detectable concentrations of 1⋅10^-5 g/dm³ up to 2.2⋅10^-4 g/dm³.

EFFECT: quantification of diphenylamine in shot products.

1 cl, 2 ex, 2 tbl, 3 dwg