METHOD FOR TEST-IDENTIFICATION OF MULTI-COMPONENT GASEOUS MIXTURES OF BENZENE, TOLUENE, PHENOL, FORMALDEHYDE, ACETONE AND AMMONIA

摘要

FIELD: chemistry.;SUBSTANCE: method for test-identification of multi-component gaseous mixtures of benzene, toluene, phenol, formaldehyde, acetone and ammonia involves forming an array of piezo sensors with different selectivity towards the analysed components. The method also involves preparing and collecting samples of equilibrium gaseous phases of sorbates and then putting them into a detection cell. The method also involves picking up and processing sorption analytical signals, calibrating sensors and constructing 'visual fingerprints' of standard and analysed mixtures. To identify benzene, toluene, phenol, formaldehyde, acetone and ammonia, an array of six different sensors is formed. To this end, electrodes of piezo crystal resonators from sorbent solutions are coated with films of Apiezon-N, a mixture of Triton X-100 with an extract of higher mycelial fungus Pleurotus Ostreatus, polyethylene glycol adipate, polyethylene glycol sebacate, polyvinyl pyrrolidone and dinonylphthalate with mass of 15-25 mcg. After injecting samples into the detection cell, the sensors are polled in the following order: the sensor with the Apiezon-N film is polled after 5 and 10 s, sensors based on the mixture of Triton X-100 with an extract of higher mycelial fungus Pleurotus Ostreatus after 20, 25, 30 s, polyethylene glycol adipate after 55 s, polyethylene glycol sebacate after 60 s, polyvinyl pyrrolidone after 70, 75 s and dinonylphthalate after 80, 85, 90 s. To predict 'visual fingerprints' of standard mixtures, a unidirectional three-layer neural network is used, which is trained based on sorption results on each sensor and physical-chemical properties of components of the mixture: molar mass, molar refraction coefficients, permittivity, density of sorbates, boiling point, pressure of saturated analyte vapour, presence and number of oxygen and nitrogen atoms and CH₃ groups or other substitutes in the molecule. During analysis of real gas systems containing benzene, toluene, phenol, formaldehyde, acetone and ammonia, the obtained 'visual fingerprints' are compared with those in the 'visual fingerprint' data base of standard mixtures. The degree of similarity and qualitative composition of the analysed mixture are determined from the shape of the fingerprints, and the area of the diagram is a quantitative criterion.;EFFECT: method for test-identification of multi-component gaseous mixtures of benzene, toluene, phenol, formaldehyde, acetone and ammonia, which enables to identify multi-component mixtures of benzene, toluene, phenol, formaldehyde, acetone and ammonia in different combinations, simple procedures for obtaining standard visual fingerprints of mixtures and short duration of analysis.;3 tbl, 3 dwg