ECD chromatogram

Figure 13.2 MDGC-ECD chromatograms of PCB fractions from sediment samples, demonstrating the separation of the enantiomers of (a) PCB 95, (b) PCB 132, and (c) PCB 149 non-labelled peaks were not identified. Reprinted from Journal of Chromatography, A 723, A. Glausch et al, Enantioselective analysis of chiral polyclilorinated biphenyls in sediment samples by multidimensional gas cliromatography-electi on-capture detection after steam distillation-solvent exti action and sulfur removal , pp. 399-404, copyright 1996, with permission from Elsevier Science.

Fig. 13. A GC-ECD chromatogram of polar pesticide fraction analyzed in cod liver oil. Column 60-m capillary column with 5% phenyl-substituted methylpolysiloxane phase (after [179] with permission)...

The purity of the purified triolein is verified as follows. According to standard procedures, replicate standard SPMDs are made using the purified triolein. The SPMDs are dialyzed and the dialysates are subjected to SEC fractionation. (Prior to SEC, dialysates should have <500 xg methyl oleate, and essentially no oleic acid.) The fractions collected from the SEC are evaluated by GC with ECD, FID, and MS. In order to pass the pre-use certification, the dialysate from a standard SPMD, after SEC, should contain less than 5 qg of methyl oleate, GC-ECD chromatograms... 

Fig. 16.19 GC-ECD chromatograms showing appearance of polybrominated diphenyl ether (PBDE) congeners, after sunlight irradiation of BDE-209 (retention time = 88.7 min) adsorbed on montmorillonite, at different times. Reprinted with permission from Ahn MY, Filley TR, Jafvert CT, Nies L, Hua I, Bezares-Cruz J (2006) Photodegradation of decabromodiphenyl ether adsorbed onto clay minerals, metal oxides, and sediment. Environ. Sci. Technol. 40 215-220. Copyright 2006. American Chemical Society...

Figure 1. HSSPME-GC-ECD chromatograms of spiked milk samples (A) skim milk ... 

Figure 1A shows the ECD chromatogram obtained for the skim milk. (From... 

Fig. 5.2. ECD chromatogram of heptafluorobutyryl derivatives of phenols. Peaks 1 = phenol 2 = 4-chlorophenol 3 = 2-chlorophenol 4 = 2-bromophenol 5 = 2,4-dichlorophenol 6 = 2,6-dichloro-phenol 7 = p-rm.-butylphenol 8 = 2,4,6-trichlorophenol 9 = 2,4,5-trichlorophenol 10 = 2,4-di-bromophenol 11= o-phenylphenol. Conditions glass column, 270 cm X 2 mm I.D. nitro-DEGS bonded GC packing nitrogen flow-rate, 33 ml/min temperature, 80°C for 2 min, then programmed at 8°C/min to 170°C. Concentrations of phenols in the initial water sample ranged from 188 ppb (peak 7) to 44 ppb (peak 6). (Reproduced from J. Chromatogr., 156 (1978) 143, by courtesy of L.L. Lamparski.)...

In addition to the three congeners mentioned before, B8-2229 (P-44), B8-1414 (P-40), B8-1945 (P-41), B8-1412, and B7-1453 have been quantified in fish [136,187], B8-806/B8-809 (P-42) was also present in selected samples [187],but B7-515 (P-32) was below the detection limits in most samples analyzed so far. Several organochlorines may coelute with B7-515 (P-32) and pretend its presence in GC/ECD chromatograms. However, at a site which was heavily contaminated with toxaphene [188], Maruya et al. found significant B7-515 (P-32) levels in the respective fish samples [189]. Tribulovich et al. identified in addition B7-1059 as a major toxaphene component in fish as well as B7-1584, B7-1715, B8-789 (P-38), and B9-718 [190]. 

Fig. 6A, B. GC/ECD chromatograms of the phenolic fraction obtained from A a women from the Faeroe islands with a relatively high OHS contamination level in her blood (A. Bergman et al., unpublished data), and B albatross [42] plasma. The structures of the identified congeners are labeled on the peaks. The number labels refer to the corresponding OH-PCB congeners listed in Table 2. The I.S. is 2,3,3, 4, 5,5, 6-heptachloro-4-biphenylol (4-OH-CB193)...

Qualitative FCB distributions of the New Bedford samples suggest that free and bound PCB s may have derived from different sources. Figure 2 presents capillary ECD chromatograms of the FL... 

Twelve sludges have been analysed for chlorobenzenes, the details of which are provided in Table 1. A typical GC-ECD chromatogram for a sludge extract is shown in Fignre 2. This illustrates the considerable complexity of sludge extracts since, even with the relative specificity of electron-capture detection, the presence of many other componnds can be detected. In onr work, the identity of the di-chlorobenzenes in selected samples was confirmed nsing gas chromatography— mass spectrometry. 

Fig. 5 Ion chromatogram of LABs (m/z 91) and ECD chromatogram of PCBs indicating anthropogenic inputs from non-point sources. The superscript on each peak of the LABs indicates the substitution position. Congeners of PCBs are numbered according to Ballschmitter et al. (1987).

Fig. 12 GC-ECD chromatograms of (a) SCCP standard with 60% Cl by weight and (b) a fish extract showing the triangles used in calculating the respective areas [62]...

Figure 6 GCxGC- t.ECD chromatogram of a mixture of 90 RGBs with HP-lxHT-8 column combination. Dotted lines connect CB congeners with the same number of chlorine substituents in the molecule the position of each CB congener within a group is determined by the substitution pattern on the biphenyl skeleton [10].

Figure 5 Overlaid GCxGC- j,ECD chromatogram on DB-1 x007-65HT column combination of PBDES (green), fluorinated PBDEs (orange), other bronminated flame retardants (red), and PBDE metabolites (blue) [27].

Figure 3.28A Comparison of three SPME/C-GC-ECD chromatograms from a blank, spiked blank and thermal desorbed blank (this and the following six figures were taken in the author s laboratory).

Figure 3.28B Overlay of SPME/C-GC-ECD chromatograms for isolating AR 1242 from a blank and a spiked blank.

Figure 3.28G Comparison of SPME vs. LLE C-GC-ECD chromatograms for the isolation and recovery of AR 1242 from a base saponified aqueous sample matrix originally derived from rat feed.

Figure 4.26 Capillary GC-ECD chromatogram for the separation and detection of chloroform, carbon 5 tetrachloride, and trichloroethylene.

Figure 4.27 Comparison of capillary GC-ECD chromatograms between a method blank and building fiberglass insulation suspected of containing AR 1260.

Figure 4 SPME-GC-ECD chromatogram of a water river sample. Elution time of short-chain chlorinated paraffins is indicated in the chromatogram. Experimental conditions GC column DB-5 (J W Scientific) 30m x 0.25mm ID, 0.25pm film thickness. (Reprinted with permission from Castells P, Santos FJ, and Galceran MT (2003) Solid-phase microextraction for the analysis of short-chain chlorinated paraffins in water samples. Journal of Chromatography A 984 1-8.)...

Figure 3 ECD chromatogram of an Aroclor mixture (A1016, A1232, A1248, A1260,1 1 1 1) on a 50m x 0.22 mm x 0. 26 pm CP Sil 19 column. (Reproduced with permission from Larsen B et al. (1992) International Journal of Environment Analytical Chemistry 47 47-68 Taylor Francis Ltd. http //www.tandf.co.uk/journals)...

Commercially available solvents such as acetone, acetonitrile, dichloromethane, hexane and pentane are invariable contaminated with ECD active substances. Concentrations vary with the quality ordered, the batch number and the supplier. Contamination should be checked by concentrating a 100 mL portion of the solvent to 50/iL in a rotary evaporator and injection of 2 pL of the concentrate into a GC with electron capture detection. No peak in the ECD chromatogram (after 10 min) should be larger than that of 0.1 pg of chlorobiphe-nyl. Otherwise, the solvent must be distilled. 

Fig. 1. GC-ECD chromatograms (60 m DB-5 column) of the PCB fraction from a Herring Gull (egg), its main prey, the Alewife (a small forage fish) and a mixture of two technical PCBs (Aroclor 1254 and 1260). PCB congeners are identified by lUPAC No. (see Table 1), H is hexachlorobenzene, E is p,p -DDE, N is t-nonachlor, PM is photomirex, and M is mirex.

Fig. 3. GC-ECD chromatograms (60 m DB-5 Column) of the PCB fraction from eggs of three fish-eating birds from the Bay of Fundy on the Atlantic coast Leach s Storm Petrel (offshore, surface feeding), Double-Crested Cormorant (nearshore, subsurface feeding) and Atlantic Puffin (offshore, subsurface feeding). Peak identities are as in Fig. 1. Peaks labelled ( ) are unidentified. 

Herring Gull eggs to an Aroclor 1254 1260 equivalent calculated from a single peak ( 138) in a capillary GC-ECD chromatogram indicated that there was little difference between the two numbers (CWS unpublished data). Further research is required to relate older data obtained by packed column GC to the sum of individual PCBs from capillary column GC. 

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