Development and Application of the Needle Trap Device
Air is one of the most important resources in the world and is essential for life. With the development of industry, air pollution is becoming a severe problem. Air Pollution not only affects the quality of the air we breathe; it also impacts the land and the water. Volatile organic compounds (VOCs), which can cause short-term and long-term health problems, are found as contaminants in both indoor air and the environment. Therefore, it is necessary to develop accurate and convenient sampling methods to determine VOCs at trace levels in both community and occupational environment. The focus of this project is to develop the needle trap devices (NTDs) with appropriate sorbents and employ them to do air samplings by diffusive or active sampling mode. For diffusive sampling, the NTD with sorbent Carboxen1000 was developed to monitor benzene, toluene, ethylbenzene and o-xylene (BTEX) in the air, coupled with GC-MS. The factors such as sorbent strength, response time, face velocity, temperature and pressure, relative humidity and sampling duration were investigated. Method validations were done both in the laboratory and in field. The results demonstrate that the NTD with Carboxen1000 is a successful diffusive sampler for monitoring Time-weighted average (TWA) concentrations of BTEX. On the other hand, the NTD with divinylbenzene (DVB) coupled with GC-MS by thermal desorption was developed for sampling and analysis of volatile thiols. The factors such as sorbent strength, desorption efficiency were investigated. The applications, such as vegetable analysis and field sampling analysis, indicate that the NTD with sorbent DVB is a successful active sampler for determine volatile thiols in food and air samples.