Environmental Monitoring

Abstract

In the field of analytical chemistry and its instrumentation, microsystem technology has been most remarkable, because it leads to on-site and real-time monitoring, high-speed and high-throughput analysis, resulting from a small sample volume, rapid operation procedure, and a small measuring device space. Although the atmospheric environment has a lot of pollutants, few researches deal with the gas phase as most of these researches have been proposed for analyzing liquid samples. Because of significant differences between the physical parameters of gas and liquid phases, such as viscosity and compressibility, the control of a stable gas–liquid equilibrium system in a microchannel is relatively difficult. If the chemicals in the environment can be easily taken into microsystems, their application to sample pretreatment microchips and downsized mass spectrometer systems will diversify further. After analyzing the simple gas–liquid equilibrium system on a microchip, for example, a gas–liquid contacting pretreatment microsystems via porous material was described, and several novel gas, liquid, and solid sample pretreatment methods were developed by utilizing mass transfer microsystems from gas, liquid, and solid phases, respectively, to the liquid phase. In the environmental monitoring of gas, liquid, and solid samples, on-site and continuous monitoring microsystems are required for hazardous nitrogen dioxide, sulfur dioxide, ozone, formaldehyde, and volatile organic compounds in the parts per trillion by volume (pptv) level in the atmospheric environment. Trace and precise analysis microsystems are needed for hazardous metal ions, harvesters, endocrine disrupter compounds, nutrition, and phosphoric and nitrogen compounds at the parts per million (ppm) level in wastewater and water samples. Environmental solid sample pretreatment microsystems are necessary for various kinds of solid samples such as nanometer-sized particles, diesel exhaust particulates, flied ash, suspended solid materials, carbon, and soil samples because such samples contain hazardous and carcinogenic compounds like dioxine, polychlorinated biphenyls, and endocrine disrupter compounds at levels lower than the ppm level.