| 摘要 |
FIELD: chemistry. ^ SUBSTANCE: invention relates to determination of ammonia content in gas, liquid and solid media. The method involves use of piezocrystal bulk acoustic wave resonators with a sorbent film on electrodes, taking a sample, preparing the sample for analysis, putting the analysed sample into a detection cell, recording the analytical signal, plotting an analytical curve öF=f(CNH3) and determination of ammonia content. Test objects are gas, liquid and solid media which contain 0.01-10 mg/m3 ammonia. There is a stage for preparing the sample for analysis: the solid phase is ground up, put into a weighing bottle, heated to 40C, passing 500-1000 m3 air through it at a rate of 40-50 cm3/min, and then the obtained gaseous mixture or analysed gas phase with volume 500-100 cm3 is passed through an alkaline solution of tetraethylmethylenediamine with mass ratio of 1-5% at a rate of 40-50 cm3/min. For analysis of liquid media, a 10 cm3 sample is taken, 0.1 cm3 of concentrated solution of tetraethylmethylenediamine is added, mixed, 5 cm3 is taken from the obtained mixture during preparation for analysis of solid, gaseous or liquid phase and kept in a weighing bottle with a polyurethane plug for 15 minutes. 1 -2 cm3 is taken from the equilibrium gas phase over the solution and put into the detection cell. Concentration of ammonia in the analysed liquid sample is found from analytical curve öF=f(CNH3) (dwg.), plotted at peak response of the piezocrystal resonator with a film in standard gaseous mixtures. Concentration of ammonia in the solid and gaseous phases is further found using formula (1) Cs=(Ca.p. Va.p.)/Vs, where Cs - is concentration of ammonia in the sample, Ca.p. - is concentration of ammonia in aqueous phase, found using the analytical curve, Vs - is volume drawn gaseous sample, Va.p. - is volume of aqueous phase. ^ EFFECT: high selectivity, sensitivity and accuracy of analysis. ^ 6 ex, 1 tbl, 1 dwg |
