METHOD OF DETERMINING PHENOL IN AIR Russian patent published in 2012 - IPC G01N30/62 

FIELD: chemistry.

SUBSTANCE: method of determining phenol in air, involving use of a piezoelectric quartz crystal resonator, applying a sensitive coating on electrodes, collecting an air sample, injecting said sample into a carrier gas stream fed into a detection cell, recording changes in oscillation frequency thereof, determining concentration of phenol using a calibration curve, characterised by that the sensitive coating applied on both sides of the piezoelectric quartz crystal resonator is in form of carbon nanotubes with weight of up to 4 mcg, the electric circuit of the flow detector with a piezoelectric sensor is combined with a computer which picks up the signal of the piezoelectric sensor in real time, content of phenol is determined at high flow rate of the carrier gas of 200-300 cm³/min, which is in form of, for example, dried air, a program is used to calculate the integral of the phenol sorption factor - the area under the output curve of the piezoelectric sensor over time (time-frequency curve) and concentration of phenol in air is determined from the calibration curve S_peak=f(C_f) or the corresponding equation S_peak=a+b C_f.

EFFECT: high accuracy of determining concentration of phenol in air on the micro- and macro-concentration level without preliminary sample concentration, lower detection limit of phenol, wider concentration boundaries of the calibration function, reproducibility of the signal, low effect of water on sorption, considerably longer operating life of the piezoelectric sensor without change in operational characteristics and considerably rapid determination.

2 ex, 2 tbl, 3 dwg