Use of sodium tetrachloromercuriate as a substrate for the determination of SO2 on the piezocrystal detector.
Environ Lett 1971; 2(1):35-45
A method for the determination of sulfur-dioxide (7446095) (SO2) by a piezocrystal detector coated with sodium-tetrachloromercuriate was described. The development of a piezocrystal detector specific for SO2 utilized a 9 megahertz quartz crystal with plated metal electrodes and sprayed various coatings to yield a smooth thin surface film specific for the gas. The coatings tested included 1 percent solutions of apiezon-N, silicone-SE30, silicone-QF1, carbowax-20M, versamid-900, and a 0.1 molar solution of sodium- tetrachloromercuriate. Vibration of the crystals was achieved using 5.5 volts applied to an oscillator, and temperature studies showed a small temperature effect on the frequency of the crystals between 25 and 40 degrees-C. Each type of coating was evaluated by injecting 50 microliters of SO2 into the piezoelectric crystal cell and determining the gas adsorption of the coating according to the Sanerbrey equation. The rank order of coating adsorption from greatest to least was sodium-tetrachloromercuriate, silicone-QF1, versamid-900, apiezon-N, carbowax-20M, silicone-SE30. The adsorption of SO2 on sodium tetrachloromercuriate was linear between 1 and 15 minutes at concentrations from 0.18 to 4.01 micrograms. The authors conclude that this coating is adequate for the determination of SO2 in ambient air.
NIOSH-Publication; NIOSH-Grant; Grants-other; Sulfur-oxides; Analytical-chemistry; Air-quality-measurement; Toxic-gases;
Author Keywords: sulfur dioxide; piezoelectric crystal; tetrachloromercuriate
Chemistry Louisiana State University Chemistry Department New Orleans, LA 70122
Other Occupational Concerns; Grants-other
Louisiana St Univ New Orleans, New Orleans, Louisiana