Simple Analytical Method for the Determination of Volatile Chloroorganic Compounds in Water Using Lipid-Coated Quartz Crystal Microbalance Sensor

A simple analytical method for the determination of volatile chloroorganic compounds, such as trichloroethylene (TCE) and tetrachloroethylene (PCE), in water using a lipid-coated quartz crystal microbalance (QCM) sensor was developed. By shaking a water sample in a sealed-bottle for 30sec, concentration equilibrium of volatile chloroorganic compounds was attained between water and headspace gas in the bottle. The frequency change of the QCM sensor, which was monitored after inserting it into the headspace of the sealed bottle, was turned out to be proportional to the concentration in water. Comparison of analytical performance of the QCM sensor and that of the gas detector tube, conventionally used for monitoring of these gases, was carried out. The former method gave a wider dynamic range of the measurement. As another means of vaporization of volatile chloroorganic compounds from the water samples, a purified air was passed into the water and circulated in a closed system for about 300sec. Then, the air containing vaporized chloroorganic compounds was transferred into a flow cell incorporating four types of QCM sensors and the frequency changes were monitored. The QCM sensor, which gave the highest sensitivity, was a 353AN coated-QCM sensor and its sensitivity was beyond 3.6Hz/ppm.