Determination of hydrogen cyanide in air using mass amplification by heavy ligand replacement on a coated quartz piezoelectric crystal

Abstract

Piezoelectric crystals coated with bis(pentan-2,4-dionato)nickel are used to detect the presence of hydrogen cyanide in the range 13–93 ppm (10 −4 mol mol −1). The displacement of the heavy ligand pentan-2,4-dione by a light molecule (HCN) yields an increase in sensitivity, compared to simple absorption of the analyte (i.e., mass amplification). A continuous flow system is used at relative humidities of 40–92%. The lifetime of such a device is limited by hydrolysis. Reproducibility from coated-crystal to coated-crystal is poor, probably owing to inconsistencies in coating techniques.