Date of Award
Master of Science in Environmental Science - (M.S.)
Chemical Engineering, Chemistry and Environmental Science
Barbara B. Kebbekus
Joseph W. Bozzelli
Volatile organics in ambient air were regularly collected on Tenax cartridges at high (10 ml/min) and low (5 ml/min) intake flows. These Tenax samples were analyzed by using a Tekmar Automatic Thermal Desorber and capillary GC system with parallel flame ionization (FID) and electron capture detectors (ECD). A series of quality assurance procedures has been established to improve and assure the accuracy and precision of sample collector and analysis. These procedures relate to performance of the Tekmar thermal desorber, recovery efficiency from the Tenax, and include studies on breakthrough and co-elution. The results demonstrate (1) that from ambient air data in East Central New Jersey, chlorocarbons, including chloroform, 1,1,1-trichloroethane, carbon tetrachloride, trichloroethylene and perchloroethylene, are present at lower levels than the hydrocarbons: hexane, benzene, toluene and p,m-xylene. Among the chlorocarbons, chloroform and trichloroethylene are present at very low trace levels (within 0.5 ppb) at sampling sites if compared to the other compounds; (2) the ECD is a preferred detector to accurately quantitate the chloro compounds, while hydrocarbons are bset quantitated by FID; (3) The accuracy and precision of Tenax sampling for most of the target compounds warrants its use as judged from studies of breakthrough as well as agreement between high and low flow samples; and (4) Tenax adsorbent is unable to efficiently trap light chlorocarbons such as methylchloride and dichloromethane. A statistical analysis of air data is presented based upon the above studies.
Liao, Chih-Hsiang, "Organics in ambient air by collection on tenax, thermal desorption,and capillary chromatography with parallel FID/ECD analysis" (1989). Theses. 1958.