Electron Capture Detection (electron + capture_detection)

Distribution by Scientific Domains


Selected Abstracts


Impact of changes in analytical techniques for the measurement of polychlorinated biphenyls and organochlorine pesticides on temporal trends in herring gull eggs

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 7 2010
Shane R. de Solla
Abstract Changes in analytical approaches during the tenure of monitoring programs for organochlorine (OC) pesticides and polychlorinated biphenyls (PCBs) may affect estimates of temporal trends. We used an in-house reference material to create multiplication factors to adjust the estimates of OC pesticides and PCBs (Aroclor equivalents) in Great Lake herring gull eggs analyzed using electron capture detection (1987,1997) to be more equivalent to estimates using mass spectrometric detection (1998,2005) as well as accompanying differences in analytical procedures. We examined temporal trends in contaminant concentrations in herring gull eggs using change point regressions, to determine whether significant changes in long-term trends were associated with analytical methodology. The highest frequency of change point occurrences shifted from 1997 (when analytical methodology was altered) to 2003 after data adjustment. The explanatory power (r2) of the regressions was lower after adjustment, although only marginally so (mean r2 difference,=,0.04). The initial rates of decline before change points in contaminant concentrations were generally slower after the data adjustment, but after any change points the declines were not significantly different. The regression models did not change for 83.3% of the cases. The effects on the interpretation of long-term temporal trends in herring gull eggs, although not negligible, were minor relative to the magnitude of the temporal changes. Environ. Toxicol. Chem. 2010;29:1476,1483. © 2010 SETAC [source]


Organochlorine contaminants in sea turtles: Correlations between whole blood and fat

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 3 2004
Jennifer M. Keller
Abstract Monitoring toxic organochlorine(OC)compounds is an important aspect in wildlife studies, especially in protected species such as sea turtles. The goal of this study was to determine whether blood OC concentrations can predict those in adipose tissue of sea turtles. Blood offers many benefits for monitoring OCs. It can be collected nondestructively from live turtles and can be sampled repeatedly for continuous monitoring. Organochlorine concentrations in blood may better represent the exposure levels of target tissues, but blood concentrations may fluctuate more than those in fatty tissues following recent dietary exposure or lipid mobilization. Paired fat and blood samples were collected from 44 live, juvenile loggerhead sea turtles and 10 juvenile Kemp's ridley sea turtle carcasses. Organochlorines were analyzed using gas chromatography with electron capture detection and mass spectrometry. Lipid-normalized OC concentrations measured in the blood significantly correlated to levels found in the fat samples of both species. This result suggests that sea turtle blood is a suitable alternative to fatty tissues for measuring OCs because blood concentrations reasonably represent those observed in the paired fat samples. However, blood OC concentrations calculated on a wet-mass basis were significantly and inversely correlated to lipid content in the fat samples. Therefore, caution should be used when monitoring spatial or temporal trends, as OC levels may increase in the blood following mobilization of fat stores, such as during long migrations, breeding, or disease events. [source]


Prenatal polychlorinated biphenyl exposures in eastern Slovakia modify effects of social factors on birthweight

PAEDIATRIC & PERINATAL EPIDEMIOLOGY, Issue 3 2008
Dean Sonneborn
Summary Polychlorinated biphenyls (PCB) were widely used for industrial purposes and consumer products, but because of their toxicity, production was banned by most industrialised countries in the late 1970s. In eastern Slovakia, they were produced until 1985. During 2002,04, a birth cohort of mothers (n = 1057) residing in two Slovak districts was enrolled at delivery, and their specimens and information were collected after birth. Congeners of PCBs were measured in maternal serum by high-resolution gas chromatography with electron capture detection. In this study, we used multiple linear regression to examine the effects of prenatal PCB exposure on birthweight adjusted for gestational age, controlling for inter-pregnancy interval, and maternal smoking, age, education, ethnicity, pre-pregnancy body mass index and height. The association between total maternal serum PCB levels and birthweight was not statistically significant. However, an interaction model indicated that maternal PCB concentrations were associated with lower birthweight in Romani boys. Based on the fitted regression model, the predicted birthweight of Romani boys at the 90th percentile of maternal PCBs (12.8 ng/mL) was 133 g lower than the predicted birthweight at the 10th percentile of maternal PCBs (1.6 ng/mL). This is a similar magnitude of effect to that observed for maternal smoking and birthweight. These results suggest that higher levels of PCBs in maternal blood sera may inhibit growth in boys, particularly in those already affected by social factors related to ethnicity. This study is consistent with previous findings that boys are more susceptible than girls to growth restriction induced by in utero organochlorine exposures, and further indicates that high PCBs may magnify the influence of social disadvantage in this vulnerable group of boys. [source]


Exposures associated with serum organochlorine levels among postmenopausal women from Western New York state

AMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 2 2002
Kirsten B. Moysich PhD
Abstract Background Organochlorines, such as 2,2-bis (4-chlorophenyl)-1,1-dichloroethylene (DDE), polychlorinated biphenyls (PCBs), and hexachlorobenzene (HCB) are lipophilic compounds that are ubiquitous in the environment and may cause adverse health effects in humans. Methods We examined the correlation between epidemiological exposure variables and serum DDE, PCB, and HCB levels in a sample of 192 healthy, female postmenopausal western New York residents; a subset of the control group from a case,control study on breast cancer risk. Usual diet, reproductive and medical histories, and other lifestyle information were obtained by an extensive in person interview. Serum levels (ng/g) of DDE, HCB, and 69 PCB congeners were determined by gas chromatography with electron capture detection. Statistical analyses included computations of crude and age and lipid adjusted correlation coefficients, as well as multiple linear regression analysis. Results Results indicated that the strongest predictors for serum DDE levels were age, serum lipids, parity, and fruit and dairy consumption. Statistically significant predictors of PCB levels included age, serum lipids, parity, and fish consumption. Serum HCB levels were related to age, serum lipids, and fruit and red meat consumption. Conclusions Our findings are consistent with previous investigations that reported strong associations between organochlorine levels and age and serum lipids. The absence of other data showing an association between fruit intake and organochlorine levels make the importance of this finding unclear. Am. J. Ind. Med. 41:102,110, 2002. © 2002 Wiley-Liss, Inc. [source]


Analytical, Risk Assessment, and Remedial Implications Due to the Co-Presence of Polychlorinated Biphenyls and Terphenyls at Inactive Hazardous Waste Sites

REMEDIATION, Issue 1 2000
James J. Pagano
Investigations conducted at three inactive hazardous waste sites in New York State have confirmed the co-presence of polychlorinated hiphenyls (PCBs) and polychlorinated terphenyls (PCTs) in soils, sediments, and biota. The PCTs at all three sites were positively identified as Aroclor 5432, with the most probable source being the hydraulic fluid Pydraul 312A utilized for high-temperature applications. The identification of the lower-chlorinated PCT formulations in environmental samples is problematical, since PCT Aroclors 5432 and 5442 are not chromatographically distinct from the higher-chlorinated (PCB) Aroclors 1254, 1260, 1262, and 1268 using conventional gas chromatography,electron capture detection. Results from this study indicate that U.S. Environmental Protection Agency (USEPA) approved PCB methods routinely utilized by most commercial laboratories based on Florisil adsorption column chromatography cleanup are inadequate to produce valid chromatographic separation and quantitative results with soils, sediment, and biota samples containing both PCBs and PCTs. The presence of co-eluting PCBs and PCTs precludes accurate quantitation due to significant differences in PCB/PCT electron capture detector response factors, and the potential for misidentification of PCT Aroclors as higher chlorinated PCB Aroclors. A method based on alumina column adsorption chromatography was used, allowing for the accurate identification and quantitation of PCB and PCT Aroclors. The results of this study suggest that the utilization of alumina adsorption column separation may have applicability and regulatory significance to other industrially contaminated sites which historically used Pydraul 312A. Inferences. [source]


Decontamination of organochlorine pesticides in Radix Codonopsis by supercritical fluid extractions and determination by gas chromatography

BIOMEDICAL CHROMATOGRAPHY, Issue 9 2006
Chunjie Zhao
Abstract A method involving depuration of 12 organochlorine pesticides (OCPs) from Radix codonopsis was developed using supercritical fluid extraction (SFE). The pesticides investigated in the study included , -, , -, , - and , -benzene hexachloride, PCNB (pentachloro-nitrobenzene), PCA (pentachloroaniline), HEPT (heptachlor), MPCPS (methyl-pentachlorophenyl sulfide), pp,-DDE [1,1-dichloro-2, 2-bis(p -chlorophenyl) ethylene], op,-DDT [1,1,1-trichloro-2-(o -chlorophenyl)-2-(p -chlorophenyl)ethane], pp,-DDD [1,1-dichloro-2-2-bis(p -chlorophenyl)ethane] and pp,-DDT [1,1,1-trichloro-2,2-bis(p -chlorophenyl)ethane]. A series of experiments was conducted to optimize the final extraction conditions as follows: pure CO2, extraction pressure 15 MPa, extraction temperature 60°C, extraction time 20 min and flow rate 55 mL/h. A GC method with electron capture detection was employed for the determination of the OCPs in Radix codonopsis. An HPLC method was developed for the quantitative determination of active constituents. SFE was used to remove the organochlorine pesticide from Radix codonopsis. The results showed that at least 93.5% of the organochlorine pesticide residues in the herb sample were removed by SPE, while 95.0% of the active constituent marker (atractylenoide III) remained. Copyright © 2006 John Wiley & Sons, Ltd. [source]


Supercritical fluid extraction for the separation of organochlorine pesticides residue in Angelica sinensis

BIOMEDICAL CHROMATOGRAPHY, Issue 7 2002
Chunjie Zhao
A method involving the simultaneous extraction and separation of 12 organochlorine pesticides (OCPs) from Angelicae sinensis was developed using supercritical fluid extraction (SFE). The pesticides in the study were ,-, ,-, ,- and ,-benzene hexachloride, PCNB (pentachloro- nitrobenzene), PCA (pentachloroaniline), HEPT (heptachlor), MPCPS (methyl-pentachlorophenyl sulfide), pp,-DDE [1,1-dichloro-2,2-bis (p -chlorophenyl) ethylene], op,-DDT [1,1,1,-trichloro-2-(o -chlorophenyl)-2-(p -chlorophenyl) ethane], pp,-DDD [1,1-dichloro-2,2-bis(p -chlorophenyl) ethane], and pp,-DDT [1,1,1,-trichloro-2,2-bis (p -chlorophenyl)ethane]. The extraction conditions were optimized as follows: pure CO2, extraction pressure 15 MPa, extraction temperature 60°C, extraction time 20,min, and flow-rate 1.5,mL/min. A GC method with electron capture detection was employed to determine the OCPs in Angelicae sinensis. An HPLC method was developed for the quantitative determination of active constituents. The SFE provided high decontamination rate of OCPs and low loss of active constituents in Angelicae sinensis. Copyright © 2002 John Wiley & Sons, Ltd. [source]