METHOD OF DETERMINING FORMIC ACID VAPORS IN WORKING ZONE AIR Russian patent published in 2005 - IPC

FIELD: analytical methods in leather industry.

SUBSTANCE: method comprises sampling, preparation of installation, and detection with registration of analytical signal followed by calculation of formic acid concentration according to calibration graph. More specifically, sample is introduced into detection cell provided with quartz piezoelectric resonator whose electrodes were preliminarily modified with acetone solution of sorbent dicyclobenzo-18-crown-6 so that mass of film after removal of solvent were 20-30 μg. Registration of analytical signal is executed in the form of response of modified electrodes of piezoelectric resonator 15 sec after introduction of sample into detection cell. Calculation of formic acid concentration is performed in terms of following formula: ΔF = 1.75C_m wherein ΔF is response of modified quartz piezoelectric resonator, Hz, and C_m is concentration of formic acid in air sample, mg/m³. Implementation of proposed method brings about following advantages: sample treatment stage is eliminated; sample assay time is reduced from 7-9 h to 35-50 min (time required by modification of electrodes and subsequent regeneration of detection cell included); number of assays carried out without replacement of sorbent is twice increased; and determination error is lowered from 25 to 14%.

EFFECT: enhanced determination efficiency.

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