Portable piezoelectric crystal detector for field monitoring of environmental pollutants

A portable field monitor was constructed by using a coated piezoelectric crystal for direct monitoring of toluene in a Danish printing plant. Toluene vapor was adsorbed onto the Pluronic F-68 coating on a quartz crystal and a decrease in frequency was observed. Various substances which could interfere with toluene determination were tested. No interference from CO, NH/sub 3/, SO/sub 2/, HCl at 100 ppm are expected. Water vapor interfered and was selectively removed using a Nafion permeation tube. The readings from the piezoelectric detector were compared to two accepted procedures for monitoring toluene, the photoionization detector and the Drager tube. Results indicate that the piezoelectric detector gave data consistent with both other methods and with better relative standard deviations than the other two. 8 references, 2 figures, 1 table.