No abstract

New, highly specific and sensitive analytical methodology has been applied to the determination of chlorinated dibenzo- p -dioxins in particulate matter. The results show that the dioxins are present in particles from many types of combustion sources and in dust and soil in the vicinity of combustion sources. The data indicate that chlorinated dioxins may occur in particulate matter from the combustion of most types of organic material, and suggest the hypothesis that chlorinated dioxins result from trace chemical reactions occurring in fire.

An analytical procedure has been developed and utilized for the determination of approximately 10 to 100 parts per trillion ( lo-'' g/g) concentrations of 2,3,7,8-tetrachlorodibenzo-pdioxin (TCDD) in fish. The technique involves digestion and extraction of the matrix followed by a series of adsorbent, and chemically-modified adsorbent, liquid column chromatographic clean-up steps. A final "residue polishing" step via elevated temperature reversed-phase high performance liquid chromatography is applied prior to detection by multiple ion mode gas chromatography-mass spectrometry. Using 13C-labeled TCDD as an internal standard and carrier, the procedure has been validated for rainbow trout from approximately 10 to 100 ppt TCDD. Relative to this range, TCDD recovery is 75 % f 25 %, and the precision of a single determination at the 95 % confidence level (2a) is f20% relative at 50 ppt TCDD concentration.One compound which has been the subject of intense analytical and toxicological investigations in recent years is 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). As a result of the presence of TCDD as a contaminant in 2,4,5-trichlorophenoxy acetic acid (2,4,5-T) and related ester herbicides and the biological effects associated with exposure to TCDD, many reports have discussed both the determination of this compound and its biological activity.Much of the work up to 1974 is contained in ( I ) , while work since that time is more scattered through the literature. Co-workers have described methods and their application to the determination of part-per-trillion (ppt, g/g) level in a variety of environmental matrices using gas chromatography-mass spectrometry (GC-MS) (2-9). O'Keefe, Meselson, and Baughman ( I O ) have recently described a neutral clean-up procedure for this determination in milk. A similar method has been described by Fukuhara e t al. for low amounts of TCDD in seafoods (11). Workers a t the National Institute for Environmental Health Sciences (12) have also described a procedure which utilizes negative chemical ionization GC-MS which apparently yields high sensitivity. In all the above methods, however, the presence of other lipophilic substances represents a severe limitation. As Hummel (3) has pointed out, many commonly-observed environmental pollutants can be interferences. As part of an investigation into the presence of some halogenated aromatic compounds in fish and water, we have analyzed a variety of fish for the presence of polychlorinated biphenyls (PCB), polybrominated biphenyl (PBB), 4,4'-dichlorodiphenyIethylene (DDE), and TCDD.In order to avoid interference from million-fold excess concentrations of these materials, we have developed a multistep clean-up procedure which is very effective at removing these halogenated aromatic compounds as well as yielding high recovery and good precision for TCDD. EXPERIMENTAL Apparatus. As described by us and co-workers (6,9), we have utilized low resolution GC-MS for the primary determination, with GC-high resolution MS for confirmation of identity. These lo...

silicone + 0.40% Poly S-179 on 80/100 mesh Permabond Methyl Silicone-10 cycle (HNU Systems Inc., Newton, MA); injection port temperature, 280 °C on-column; carrier gas, helium at 14 cm3/min; separator, single stage glass jet operating at column temperature; electron energy, 70 eV. TCDD analyses conditions: column temperature, 246 °C isothermal; ions monitored, native TCDDs at m/e 320, 322, and 324, and 13C-2378-TCDD internal standard at m/e 332. Higher chlorinated dioxin analyses conditions: column temperature, programmed from 230 to 300 °C at 10 °C/min and hold at maximum; ions monitored, native HCDDs at m/e 388, 390, and 392, native H7CDDs at m/e 422, 424, and 426, and native OCDD at m/e 458, 460, and 462. 13C-123478-HCDD and l3C-OCDD are monitored at m/e 398 and 470, respectively.Environmental Particulate Samples. Industrial Dust. Particulates were removed from the air intake filtration system from a research building located in Midland, MI.Electrostatically Precipitated Fly Ash. Particulates were collected from the ash-removal system associated with the electrostatic precipitator on the Nashville Thermal Transfer Corp. refuse incinerator located in Nashville, TN. Activated Municipal Sludge. Representative samples were removed from the center of a commercially purchased 20-kg bag of Milwaukee Milorganite. Urban Particulate Matter. Standard Reference Material No. 1648 was obtained from the National Bureau of Standards (NBS).

By controlled flow pyrolysis conditions, various combinations of di-, tri-, and tetrachlorophenols were reacted to form tetrachlorodlbenzo-p-dloxins (TCDDs). These reaction products were separated by high performance liquid chromatography (HPLC) and were characterized by gas chromatography-mass spectrometry (GC-MS). This combination of HPLC and GC-MS allowed assignment of Identity to all 22 Isomers of TCDD. Applications of this selective analysis to determination of TCDD In a variety of samples are also discussed.Recently considerable attention has been directed toward understanding the formation, distribution, and transport properties of chlorinated aromatic compounds in the environment. Polychlorinated dibenzo-p-dioxins (CDDs) are one class of such compounds that have been identified at trace