Analysis electron capture detection

The special problems for vaUdation presented by chiral separations can be even more burdensome for gc because most methods of detection (eg, flame ionization detection or electron capture detection) in gc destroy the sample. Even when nondestmctive detection (eg, thermal conductivity) is used, individual peak collection is generally more difficult than in Ic or tic. Thus, off-line chiroptical analysis is not usually an option. Eortunately, gc can be readily coupled to a mass spectrometer and is routinely used to vaUdate a chiral separation. 

The analysis of mefloquine in blood, using packed-column sfc, a mobile phase consisting of / -pentane modified with 1% methanol and 0.15% -butylamine, and electron capture detection has been reported (92). The method compares favorably to a previously pubflshed hplc-based procedure having a detection limit of 7.5 ng/mLin 0.1 mL blood sample. 

The first bioanalytical application of LC-GC was presented by Grob et al. (119). These authors proposed this coupled system for the determination of diethylstilbe-strol in urine as a replacement for GC-MS. After hydrolysis, clean-up by solid-phase extraction and derivatization by pentafluorobenzyl bromide, the extract was separated with normal-phase LC by using cyclohexane/1 % tetrahydrofuran (THE) at a flow-rate of 260 p.l/min as the mobile phase. The result of LC-UV analysis of a urine sample and GC with electron-capture detection (ECD) of the LC fraction are shown in Ligures 11.8(a) and (b), respectively. The practical detection limits varied between about 0.1 and 0.3 ppb, depending on the urine being analysed. By use of... 

Several methods are available for the analysis of trichloroethylene in biological media. The method of choice depends on the nature of the sample matrix cost of analysis required precision, accuracy, and detection limit and turnaround time of the method. The main analytical method used to analyze for the presence of trichloroethylene and its metabolites, trichloroethanol and TCA, in biological samples is separation by gas chromatography (GC) combined with detection by mass spectrometry (MS) or electron capture detection (ECD). Trichloroethylene and/or its metabolites have been detected in exhaled air, blood, urine, breast milk, and tissues. Details on sample preparation, analytical method, and sensitivity and accuracy of selected methods are provided in Table 6-1. 

Residue analytical chemistry has extended its scope in recent decades from the simple analysis of chlorinated, lipophilic, nonpolar, persistent insecticides - analyzed in the first Si02 fraction after the all-destroying sulfuric acid cleanup by a gas chro-matography/electron capture detection (GC/ECD) method that was sometimes too sensitive to provide linearity beyond the required final concentration - to the monitoring of polar, even ionic, hydrophilic pesticides with structures giving the chemist no useful feature other than the molecule itself, hopefully to be ionized and fragmented for MS or MS" detection. 

Analytical methods for parent chloroacetanilide herbicides in soil typically involve extraction of the soil with solvent, followed by solid-phase extraction (SPE), and analysis by gas chromatography/electron capture detection (GC/ECD) or gas chromatog-raphy/mass spectrometry (GC/MS). Analytical methods for parent chloroacetanilides in water are similarly based on extraction followed by GC with various detection techniques. Many of the water methods, such as the Environmental Protection Agency (EPA) official methods, are multi-residue methods that include other compound classes in addition to chloroacetanilides. While liquid-liquid partitioning was used initially to extract acetanilides from water samples, SPE using... 

Glausch, A., Blanch, G.P., Schurig, V. (1996). Enantioselective analysis of chiral polychlorinated biphenyls in sediment samples by multidimensional gas chromatography-electron-capture detection after steam distillation-solvent extraction and sulfur removal. J. Chromatogr. A 723, 399 104. 

Eklund [175] developed a method for sensitive gas chromatographic analysis of monosaccharides in seawater, using trifluoracetyl derivatisation and electron capture detection. It is difficult to determine accurately the monosaccharide concentration by this method because a number of chromatographic peaks result from each monosaccharide. 

Trichlorofluoromethane and dichlorofluoromethane have been determined in seawater using headspace analysis and gas chromatography with electron capture detection [226]. 

Techniques for analysis of different mercury species in biological samples and abiotic materials include atomic absorption, cold vapor atomic fluorescence spectrometry, gas-liquid chromatography with electron capture detection, and inductively coupled plasma mass spectrometry (Lansens etal. 1991 Schintu etal. 1992 Porcella etal. 1995). Methylmercury concentrations in marine biological tissues are detected at concentrations as low as 10 pg Hg/kg tissue using graphite furnace sample preparation techniques and atomic absorption spectrometry (Schintu et al. 1992). 

Spectrophotometric determination with 4-hexylresorcinol and a fluorometric method with m-aminophenol are the most commonly used procedures for the determination of acrolein. However, gas chromatography and high-performance liquid chromatography procedures are also used (USEPA 1980 Kissel etal. 1981 Nishikawa and Hayakawa 1986). Acrolein concentrations in rainwater between 4 and 200 pg/L can be measured rapidly (less than 80 min) without interference from related compounds the method involves acrolein bromination and analysis by gas chromatography with electron capture detection (Nishikawa and Hayakawa 1986). Kissel etal. (1981) emphasize that water samples from potential acrolein treatment systems require the use of water from that system in preparing blanks, controls, and standards and that acrolein measurements should be made at the anticipated use concentrations. 

Methods have been described for determining chlorinated aliphatic hydrocarbons in soil and chemical waste disposal site samples. The latter method involves a simple hexane extraction and temperature programmed gas chromatographic analysis using electron capture detection and high resolution glass capillary columns. Combined gas chromatography-mass spectrometry was used to confirm the presence of the chlorocarbons in the samples [4],... 

Petrick G, Schulz DE, Duinker JC. 1988. Clean-up of environmental samples by high-performance liquid chromatography for analysis of organochlorine compounds by gas chromatography with electron- capture detection. J Chromatogr 435(1 ) 241 -248. 

Stan HJ, Mrowetz D. 1983. Residue analysis of pesticides in food by 2 dimensional gas chromatography with capillary columns and parallel detection with flame photometric and electron capture detection. J Chromatogr 279(0) 173-188. 

Bedard and May [452] used congener-specific GC with electron capture detection and mass spectrometric detection to determine the PCBs in sediments of Woods Pond (Lennox,MA). The congener distributions of all samples showed the hexa-, hepta-, and octachlorobiphenyls characteristic of Aroclor 1260, but key hexa- and hepta-CBs had decreased by as much as 45% relative to Aroclor 1260, and the tri-, tetra-, and penta-CBs had increased. GC-MS analysis revealed unusual tetra-, penta-, and hexa-CBs, many containing 2,4- and 2,4,6-chloro-phenyl rings, which are uncommon in higher Aroclors, and provided strong... 

Non-linear concentration/response relationships are as common in pesticide residue analysis as in analytical chemistry in general. Although linear approximations have traditionally been helpful the complexity of physical phenomena is a prime reason that the limits of usefulness of such an approximation are frequently exceeded. In fact, it should be regarded the rule rather than the exception that calibration problems cannot be handled satisfactorily by linear relationships particularly as the dynamic range of analytical methods is fully exploited. This is true of principles as diverse as atomic absorption spectrometry (U. X-ray fluorescence spectrometry ( ), radio-immunoassays (3), electron capture detection (4) and many more. 

Omura M, Hashimoto K, Ohta K, et al. 1990. Relative retention time diagram as a useful tool for gas chromatographic analysis and electron-capture detection of pesticides. J Assoc Off Anal Chem 73(2) 300-306. 

J.M.P. Douse, Trace analysis of explosives at the low nanogram level in handswab extracts using columns of Amberlite XAD-7 porous polymer beads and sdica capillary column gas chromatography with thermal energy analysis and electron capture detection , J. Chromatogr., 328 (1985) 155-165. 

Xu T, Cho IK, Wang D, Rubio FM, Shelver WL, Gasc AME, Li J, Li QX (2009) Suitability of magnetic particle immunoassay for the analysis of PBDEs in Hawaiian euryhaline fish and crabs in comparison with gas chromatography/electron capture detection-ion trap mass spectrometry. Environmental Pollution 157 417 22... 

For the detection, gas chromatography (GC) [15,18-20, 28] and liquid chromatography (LC) [14—16, 21, 22, 24, 26-29] coupled with mass spectrometry (MS) or tandem mass spectrometry (MS/MS) have been the techniques most frequently used in the determination of pesticides in ground water. Examples of the application of both techniques in the area of study, Catalonia, are the work of Garrido et al. [17], who used GC-MS and GC with electron capture detection (ECD) for the analysis of 44 pesticides in groundwater samples from Catalonia and that of Kampioti et al. [25], who used online SPE-LC-MS/MS to analyse 20 pesticides in river water and... 

The inherent insensitivity of these methods prompted an evaluation of gas-liquid chromatography with electron capture detection for the analysis of TRIS. Due to the... 

ECD = electron capture detection GC = gas chromatography GPC = gel permeation chromatography HRMS = high resolution mass spectrometry LC = liquid chromatography MS = mass spectrometry NAA = neutron activation analysis NCI = negative chemical ionization PBDEs = polybrominated diphenyl ethers... 

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