Gas Chromatography-triple Quadrupole Mass Spectrometry Research Articles

Determination of Ultratrace Polychlorinated Dibenzo-p-dioxins and Dibenzofurans by Gas Chromatography-Triple Quadrupole Mass Spectrometry

In this study a gas chromatography-tandem mass spectrometry (GC/MS/MS) method with a triple quadrupole mass spectrometer was developed for ultratrace analysis of seventeen 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). The GC and MS/MS parameters were optimized to improve the separation and resolution of the target compounds. In multiple reaction monitoring mode, two pairs of precursor ions and product ions were selected for each target compound for qualitative and quantitative analysis. The average relative response factors were calculated from five-point calibration (0.5-2000 μg L−1) curves for the 17 PCDD/F congeners. The relative standard deviations of all the congeners were <11%. The lower limit of detection ranged from 0.05 to 0.34 μg L−1. The method was applied to analysis of certified reference materials, including one solution sample and four sediment samples. The sediment samples were extracted by accelerated solvent extraction, and then purified using a Power-Prep(tm) automatic cleanup system. The precision of the PCDD/Fs quantitation in the solution sample was determined, and the relative standard deviations were <4%. The results for the solution and sediment samples agreed with their certified values. Consequently, this GC/MS/MS method can be proposed as an alternative to the relatively expensive high-resolution MS method for monitoring PCDD/Fs.

Preparation and characterization of amino functionalized nano-composite material and its application for multi-residue analysis of pesticides in cabbage by gas chromatography–triple quadrupole mass spectrometry

In this paper, a novel and recyclable amino-functionalized nano-composite material (NCM) using tetraethylenepentamine (TEPA) as a coupling agent was synthesized. The properties of the TEPA-NCM were characterized by transmission electron microscopy (TEM), Fourier transform infrared analysis (FTIR), thermogravimetric analysis (TGA) and elemental analysis (EA). An effective dispersive solid-phase extraction (dSPE) procedure using the TEPA-NCM was developed, and comparative studies were carried out among Carbon/NH 2 SPE, primary secondary amine (PSA) dSPE and TEPA-NCM dSPE. The results showed that TEPA-NCM dSPE was faster, easier and more effective to clean and enrich than the Carbon/NH 2 cartridges, and the TEPA-NCM was much more effective to remove the pigments in vegetable samples than the PSA materials. The TEPA-NCM could be reused at least five times without much sacrifice of the cleanup efficiency. Furthermore, a gas chromatography–triple quadrupole mass spectrometry (GC–QqQ-MS/MS) method was established for the simultaneous determination of 29 pesticides (such as organochlorine and organophosphorus pesticides) in vegetables by dSPE using acetonitrile as an extraction solvent and TEPA-NCM as an adsorbent instead of PSA. The recoveries were in the range of 75–114% for all analytes except for trans-chlordane. The RSDs were in the range of 2–17%. The linearities were in the range of 0.4–100.0 μg/kg with determination coefficients ( r 2) higher than 0.986 for all compounds. The limits of detection (LODs) for all pesticides were less than 0.29 μg/kg and the limits of quantification (LOQs) were between 0.17 and 0.95 μg/kg. The developed method was applied to fifteen real vegetable samples, and it was confirmed that the TEPA-NCM was one of a kind of highly effective dSPE materials used for the pesticides analyses.

Validation of a GC–MS/MS method for simultaneous determination of 86 persistent organic pollutants in marine sediments by pressurized liquid extraction followed by stir bar sorptive extraction

A multiresidue method for the analysis of 86 persistent pollutants in marine sediments at ultra-trace level has been developed and validated using pressurized liquid extraction (PLE) and stir-bar sorptive extraction (SBSE) coupled with thermal desorption and gas chromatography–triple quadrupole mass spectrometry (TD–GC–MS/MS QqQ). The compounds analyzed belong to various families such as polychlorinated biphenyls, polycyclic aromatic hydrocarbons, polybrominated diphenylethers, organophosphorus and organochlorine pesticides and other pesticides such as urons, and triazines. The analytes have very different polarities and logKow values, which is an important parameter in the optimization of a SBSE method. Due to PLE high efficiency and throughput rates, along with the proven ability for multiresidue analysis and excellent sensitivity of SBSE, we present an efficient method. The limits of quantification obtained ranged from 0.014 to 1.0ngg−1, with detection limits below pgg−1 levels. In order to validate the proposed methodology, quality parameters such as recovery, linearity and reproducibility were studied. Recoveries ranged from 63% to 119%, reproducibility (in terms of Relative Standard Deviation for ten determinations) was lower than 35% in all cases, and determination coefficients higher than 0.990 for all analytes. The main factors that affect PLE, SBSE and GC–MS/MS procedures were optimized. The method was applied to the analysis of nine marine sediments obtained from the nine main submarine wastewater discharge points (emissaries) presents along the coast of Tenerife Island (Canary Islands, Spain).

Sarcosine as a marker in prostate cancer progression: a rapid and simple method for its quantification in human urine by solid-phase microextraction–gas chromatography–triple quadrupole mass spectrometry

Sarcosine is an amino acid derivative of N-methylglycine and is involved in the amino acid metabolism and methylation processes that are enriched during prostate cancer progression. It could also serve as a new target to be measured during therapeutic interventions and help in the identification of aggressive tumors for radical treatment. In this study, we present a new urine test that can help early diagnosis of prostate cancer. The method for the quantification of sarcosine in urine consists of a solid-phase microextraction (SPME) step followed by gas chromatography-triple quadrupole mass spectrometry analysis. We used a preliminary derivatization step with ethyl chloroformate/ethanol and the corresponding ester was then extracted by SPME in immersion mode. Several fibers were evaluated and the optimization of the parameters affecting the SPME process was carried out using an experimental design. The optimal values were 20 min extraction time, 10% NaCl, and 270°C using a divinylbenzene/Carboxen/polydimethylsiloxane fiber. The triple quadrupole analyzer acquired data in selected reaction monitoring mode, allowing us to obtain reconstructed chromatograms with well-defined chromatographic peaks. The accuracy and precision of this method were evaluated at concentrations of 70, 250, and 800 ng/ml and were found to be acceptable. Very satisfactory values (0.10 and 0.16 ng/ml, respectively) were also achieved for the limit of detection and the limit of quantification. The proposed protocol represents a rapid, simple, selective, and sensitive tool to quantify sarcosine in urine samples for prostate cancer diagnosis and for a screening test.

A fast, comprehensive screening method for doping agents in urine by gas chromatography–triple quadrupole mass spectrometry

The use of performance enhancing drugs in sports is prohibited. For the detection of misuse of such substances gas chromatography or liquid chromatography coupled to mass spectrometry are the most frequently used detection techniques. In this work the development and validation of a fast gas chromatography tandem mass spectrometric method for the detection of a wide range of doping agents is described. The method can determine 13 endogenous steroids (the steroid profile), 19-norandrosterone, salbutamol and 11-nor-Δ9-tetrahydrocannabinol.9carboxylic acid in the applicable ranges and to detect qualitatively over 140 substances in accordance with the minimum required performance levels of the World Anti-Doping Agency in 1 ml of urine. The classes of substances included in the method are anabolic steroids, β2-agonists, stimulants, narcotics, hormone antagonists and modulators and beta-blockers. Moreover, using a short capillary column and hydrogen as a carrier gas the run time of the method is less than 8 min.

Rapid determination of organophosphorous pesticides in leeks by gas chromatography–triple quadrupole mass spectrometry

A rapid multi-residue method was developed for the determination of 20 organophosphorous pesticide residues in leeks by gas chromatography coupled to triple quadrupole mass spectrometry (GC–QqQ-MS/MS). The method was based on the modified QuEChERS sample preparation method. After microwave pre-treatment, leek samples were extracted with acetonitrile containing acetic acid 0.1% and cleaned by dispersive solid phase extraction. The QqQ analyser acquired data in selected reaction monitoring (SRM) mode. Recoveries of 20 organophosphorous pesticides ranged from 81.0% to 109.4% with the relative standard deviations (RSD) below 10.4%. The limits of detection (LODs) were 0.07–1.5 μg/kg. The limits of quantitation (LOQs) ranged from 0.25 to 5 μg/kg. Ten leek samples were analysed for method application.

Comparison of ultrasonic and pressurized liquid extraction for the analysis of polycyclic aromatic compounds in soil samples by gas chromatography coupled to tandem mass spectrometry

A pressurized liquid extraction (PLE) method has been optimized for the determination of polycyclic aromatic hydrocarbons (PAHs) in soil samples and it was compared with ultrasonic extraction. The extraction step was followed by gas chromatography–triple quadrupole mass spectrometry (GC–QqQ-MS/MS) analysis. Parameters such as type of solvent, extraction time, extraction temperature and number of extractions were optimized. There were no significant differences among the two extraction methods although better extraction efficiencies were obtained when PLE was used, minimizing extraction time and solvent consumption. PLE procedure was validated, obtaining limits of detection (LODs) ranging from 0.02 to 0.75 μg kg −1 and limits of quantification (LOQs) ranging from 0.07 to 2.50 μg kg −1 for the selected PAHs. Recoveries were in the range of 59–110%, except for naphthalene, which was the most volatile PAH. Finally, the method was applied to real soil samples from Southeast of Spain. PAHs concentrations were low, and phenanthrene, pyrene, fluorene, benzo[ a]pyrene and chrysene were the most frequently detected analytes in the samples.

Comparative study of pesticide multi-residue extraction in tobacco for gas chromatography–triple quadrupole mass spectrometry

This study was performed to apply the more rapid and accurate sample preparation, and the high selectivity and sensitivity of the analyte detection by gas chromatography–triple quadrupole mass spectrometry (GC–MS/MS). We compared with the three-sample preparation methods of pesticide residues in tobacco such as the conventional liquid–liquid extraction (LLE), pressurized liquid extraction (PLE) and QuEChERS (quick, easy, cheap, effective, rugged and safe) methods. These methods were validated for 49 pesticides in the CORESTA Agrochemical Advisory Committee guide and amenable to GC–MS/MS determination. LLE with acetonitrile, and PLE with acetone were followed by solid-phase extraction (SPE) and analyzed by GC–MS/MS. In QuEChERS method, the effects of sorbents, such as primary secondary amine (PSA), octadecylsilane (C 18) and graphitized carbon black (GCB), and matrix of the analytes in tobacco types, such as flue-cured, burley and oriental were investigated. MS/MS acquisition provided high specificity and selectivity for pesticides and low limit of detection and quantification. QuEChERS by using PSA alone and the matrix-matched standards gave good recoveries and RSD values in three types of tobaccos. The method yielded higher and more consistent recoveries of these analytes than LLE and PLE. QuEChERS method was no needed to be complex clean-up procedure and would be used to rapid and sensitive analysis of pesticides as an alternative to LLE and PLE methods.

Application of gas chromatography-triple quadrupole mass spectrometry in the quantification-confirmation of pesticides and polychlorinated biphenyls in eggs at trace levels

A new multiresidue method has been developed and validated for the simultaneous analysis of 57 compounds, including organochlorine and organophosphorus pesticide residues (OCPs and OPPs) and polychlorinated biphenyls (PCBs), in eggs at trace levels by gas chromatography coupled to triple quadrupole mass spectrometry (GC-QqQ-MS/MS). Egg samples were extracted by a simple and fast matrix solid phase dispersion (MSPD) procedure using C18 as sorbent, and ethyl acetate and acetonitrile saturated in n-hexane (85:15, v/v) as elution solvent with a simultaneous clean up with Florisil in-line. The QqQ analyzer acquired data in selected reaction monitoring (SRM) mode, permitting both quantification and confirmation in a single injection with a running time reduced up to 17.70 min. Recovery was in the range of 70–110% and 70–106% at 15 and 50 μg/kg, respectively. Precision values expressed as relative standard deviation (RSD) were lower than 20%. Linearity in the range of 10–150 μg/kg provided determination coefficients ( R 2) higher than 0.98 for all compounds. Limits of detection (LODs) for pesticides were ≤2.25 μg/kg and limits of quantification (LOQs) ranged from 0.02 to 7.78 μg/kg. LODs for PCBs were ≤0.41 μg/kg and LOQ were ≤0.71 μg/kg. The method was applied to real samples. Endosulfan sulphate and p, p′-DDE were found in two samples at concentrations below the first calibration level.

Characterization of recovery profiles using gas chromatography-triple quadrupole mass spectrometry for the determination of pesticide residues in meat samples

The assessment of the recovery factor with the analyte concentration in meat samples has been studied for the determination of organochlorine and organophosphorus pesticides in meat by gas chromatography-triple quadrupole mass spectrometry (GC–MS/MS). For that purpose, recent IUPAC recommendations, which distinguishes between two terms, recovery factor and apparent recovery, have been followed. Besides, the systematic error due to the matrix effect has been evaluated by a new term recently proposed, calibration recovery. Recovery profiles were obtained analyzing spiked blank matrix, where the analytes were added before and after the extraction procedure. In a first step, the quantification of the compounds was carried out using a solvent calibration curve. The systematic errors due to the matrix effect during the quantification step and the error due to the sample treatment have been evaluated. Both apparent and calibration recovery components depend on the actual analyte concentration in the sample while the recovery factor remains constant except for analyte concentration close to quantification limit. In addition, the concentration limits, from which an acceptable recovery value (70–110%) can be obtained, are given. If spiked samples are quantified by matrix-matched calibration, the matrix effect is minimized and the calibration recovery component is 100%, and apparent recovery only depends on the recovery factor. The obtained values indicate recovery factor does not depend on the analyte concentration, except for those values closed to quantification limit.

Multiresidue analysis of organochlorine and organophosphorus pesticides in muscle of chicken, pork and lamb by gas chromatography–triple quadrupole mass spectrometry

A method was optimized and validated for the simultaneous determination of residues of organochlorine (OCPs) and organophosphorus (OPPs) pesticides in meat samples from chicken, pork and lamb. The method is based in the extraction of homogenized meat mixed with sodium sulphate and ethyl acetate in polytron, although both Soxhlet and accelerated solvent extraction (ASE) were also tested. Then, a clean-up step by gel permeation chromatography (GPC) was applied, before the final determination by gas chromatography (GC) coupled to a triple quadrupole (QqQ) mass spectrometry (MS) detection system. Confirmation criteria of the pesticides were based in the 2002/657/EC European Commission Decision that establishes at least three identification points (IPs) for organic residues in live animals and animal products. The analytical process was validated in each matrix by the analysis of spiked blank samples. Performance characteristics, such as linearity, detection limit (LOD), quantitation limit (LOQ), precision and recovery were studied. Recoveries and precision values were 70.0–90.0% and 15%, respectively, for the bulk majority of pesticides. LOD < 2.0 and LOQ < 5.0 μg/kg were obtained for all the target compounds, except for acephate. The proposed analytical methodology was applied to the analysis of the pesticides in 30 samples, 10 from chicken, 10 from pork and 10 from lamb. Only three OCPs, endosulfan α, endosulfan sulfate and dichloran were detected in three different lamb samples, while endosulfan α was detected in only one pork sample, at concentration levels lower than the LOQ values. However, pesticide residues were not found in any of the other 10 chicken samples analyzed.

Acetylcholine suppresses the propagation of excitation in the rat visual cortex revealed by optical recording with voltage-sensitive dye

A multiresidue method for the analysis of 86 persistent pollutants in marine sediments at ultra-trace level has been developed and validated using pressurized liquid extraction (PLE) and stir-bar sorptive extraction (SBSE) coupled with thermal desorption and gas chromatography–triple quadrupole mass spectrometry (TD–GC–MS/MS QqQ). The compounds analyzed belong to various families such as polychlorinated biphenyls, polycyclic aromatic hydrocarbons, polybrominated diphenylethers, organophosphorus and organochlorine pesticides and other pesticides such as urons, and triazines. The analytes have very different polarities and log Kow values, which is an important parameter in the optimization of a SBSE method. Due to PLE high efficiency and throughput rates, along with the proven ability for multiresidue analysis and excellent sensitivity of SBSE, we present an efficient method. The limits of quantification obtained ranged from 0.014 to 1.0 ng g−1, with detection limits below pg g−1 levels. In order to validate the proposed methodology, quality parameters such as recovery, linearity and reproducibility were studied. Recoveries ranged from 63% to 119%, reproducibility (in terms of Relative Standard Deviation for ten determinations) was lower than 35% in all cases, and determination coefficients higher than 0.990 for all analytes. The main factors that affect PLE, SBSE and GC–MS/MS procedures were optimized. The method was applied to the analysis of nine marine sediments obtained from the nine main submarine wastewater discharge points (emissaries) presents along the coast of Tenerife Island (Canary Islands, Spain).

The effects of disparity in the peripheral field on human smooth pursuit eye movement

A multiresidue method for the analysis of 86 persistent pollutants in marine sediments at ultra-trace level has been developed and validated using pressurized liquid extraction (PLE) and stir-bar sorptive extraction (SBSE) coupled with thermal desorption and gas chromatography–triple quadrupole mass spectrometry (TD–GC–MS/MS QqQ). The compounds analyzed belong to various families such as polychlorinated biphenyls, polycyclic aromatic hydrocarbons, polybrominated diphenylethers, organophosphorus and organochlorine pesticides and other pesticides such as urons, and triazines. The analytes have very different polarities and log Kow values, which is an important parameter in the optimization of a SBSE method. Due to PLE high efficiency and throughput rates, along with the proven ability for multiresidue analysis and excellent sensitivity of SBSE, we present an efficient method. The limits of quantification obtained ranged from 0.014 to 1.0 ng g−1, with detection limits below pg g−1 levels. In order to validate the proposed methodology, quality parameters such as recovery, linearity and reproducibility were studied. Recoveries ranged from 63% to 119%, reproducibility (in terms of Relative Standard Deviation for ten determinations) was lower than 35% in all cases, and determination coefficients higher than 0.990 for all analytes. The main factors that affect PLE, SBSE and GC–MS/MS procedures were optimized. The method was applied to the analysis of nine marine sediments obtained from the nine main submarine wastewater discharge points (emissaries) presents along the coast of Tenerife Island (Canary Islands, Spain).

1611 Acetylcholine suppresses the propagation of excitation in the rat visual cortex revealed by optical recording with voltage-sensitive dye

A multiresidue method for the analysis of 86 persistent pollutants in marine sediments at ultra-trace level has been developed and validated using pressurized liquid extraction (PLE) and stir-bar sorptive extraction (SBSE) coupled with thermal desorption and gas chromatography–triple quadrupole mass spectrometry (TD–GC–MS/MS QqQ). The compounds analyzed belong to various families such as polychlorinated biphenyls, polycyclic aromatic hydrocarbons, polybrominated diphenylethers, organophosphorus and organochlorine pesticides and other pesticides such as urons, and triazines. The analytes have very different polarities and log Kow values, which is an important parameter in the optimization of a SBSE method. Due to PLE high efficiency and throughput rates, along with the proven ability for multiresidue analysis and excellent sensitivity of SBSE, we present an efficient method. The limits of quantification obtained ranged from 0.014 to 1.0 ng g−1, with detection limits below pg g−1 levels. In order to validate the proposed methodology, quality parameters such as recovery, linearity and reproducibility were studied. Recoveries ranged from 63% to 119%, reproducibility (in terms of Relative Standard Deviation for ten determinations) was lower than 35% in all cases, and determination coefficients higher than 0.990 for all analytes. The main factors that affect PLE, SBSE and GC–MS/MS procedures were optimized. The method was applied to the analysis of nine marine sediments obtained from the nine main submarine wastewater discharge points (emissaries) presents along the coast of Tenerife Island (Canary Islands, Spain).

Trihalomethanes and Other Environmental Factors That Contribute to Colorectal Cancer.

Research ArticleOpen AccessTrihalomethanes and Other Environmental Factors That Contribute to Colorectal Cancer. RL Melnick, JK Dunnick, DP Sandler, MR Elwell, and JC Barrett RL Melnick National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709 USA. Search for more papers by this author , JK Dunnick National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709 USA. Search for more papers by this author , DP Sandler National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709 USA. Search for more papers by this author , MR Elwell National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709 USA. Search for more papers by this author , and JC Barrett National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709 USA. Search for more papers by this author Published:1 January 1994https://doi.org/10.1289/ehp.94102586Cited by:14AboutSectionsPDF ToolsDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InReddit FiguresReferencesRelatedDetailsCited By Domínguez-Tello A, Arias-Borrego A, García-Barrera T and Gómez-Ariza J (2017) A two-stage predictive model to simultaneous control of trihalomethanes in water treatment plants and distribution systems: adaptability to treatment processes, Environmental Science and Pollution Research, 10.1007/s11356-017-9629-6, 24:28, (22631-22648), Online publication date: 1-Oct-2017. Iqbal M (2016) Vicia faba bioassay for environmental toxicity monitoring: A review, Chemosphere, 10.1016/j.chemosphere.2015.09.048, 144, (785-802), Online publication date: 1-Feb-2016. Charisiadis P and Makris K (2014) A sensitive and fast method for trihalomethanes in urine using gas chromatography–triple quadrupole mass spectrometry, Journal of Chromatography B, 10.1016/j.jchromb.2013.11.060, 947-948, (17-22), Online publication date: 1-Feb-2014. Henry H (2013) EPA's Stage 2 Disinfection Byproducts Rules (DBPR) and Northern Kentucky Water: An Economic and Scientific Review, Dose-Response, 10.2203/dose-response.12-056.Henry, 11:4, (dose-response.1), Online publication date: 1-Oct-2013. Card J, Fikree H, Haighton L, Lee-Brotherton V, Wan J and Sangster B (2012) Lack of human tissue-specific correlations for rodent pancreatic and colorectal carcinogens, Regulatory Toxicology and Pharmacology, 10.1016/j.yrtph.2012.10.001, 64:3, (442-458), Online publication date: 1-Dec-2012. Leme D and Marin-Morales M (2009) Allium cepa test in environmental monitoring: A review on its application, Mutation Research/Reviews in Mutation Research, 10.1016/j.mrrev.2009.06.002, 682:1, (71-81), Online publication date: 1-Jul-2009. MacLehose R, Savitz D, Herring A, Hartmann K, Singer P and Weinberg H (2008) Drinking Water Disinfection By-Products and Time to Pregnancy, Epidemiology, 10.1097/EDE.0b013e31816a23eb, 19:3, (451-458), Online publication date: 1-May-2008. Maffei F, Buschini A, Rossi C, Poli P, Forti G and Hrelia P (2005) Use of the Comet test and micronucleus assay on human white blood cells for in vitro assessment of genotoxicity induced by different drinking water disinfection protocols, Environmental and Molecular Mutagenesis, 10.1002/em.20139, 46:2, (116-125), . Kargalioglu Y, McMillan B, Minear R and Plewa M (2002) Analysis of the cytotoxicity and mutagenicity of drinking water disinfection by-products inSalmonella typhimurium, Teratogenesis, Carcinogenesis, and Mutagenesis, 10.1002/tcm.10010, 22:2, (113-128), . HUFF J (1999) Long-Term Chemical Carcinogenesis Bioassays Predict Human Cancer Hazards: Issues, Controversies, and Uncertainties, Annals of the New York Academy of Sciences, 10.1111/j.1749-6632.1999.tb08077.x, 895:1 UNCERTAINTY I, (56-79), Online publication date: 1-Dec-1999. Boorman G (2018) Drinking water disinfection byproducts: review and approach to toxicity evaluation., Environmental Health Perspectives, 107:suppl 1, (207-217), Online publication date: 1-Feb-1999. Koivusalo M and Vartiainen T Drinking Water Chlorination By-Products And Cancer, Reviews on Environmental Health, 10.1515/REVEH.1997.12.2.81, 12:2 Doyle T, Zheng W, Cerhan J, Hong C, Sellers T, Kushi L and Folsom A (1997) The association of drinking water source and chlorination by-products with cancer incidence among postmenopausal women in Iowa: a prospective cohort study., American Journal of Public Health, 10.2105/AJPH.87.7.1168, 87:7, (1168-1176), Online publication date: 1-Jul-1997. Carvalho E, Consolin Filho N, Venancio E, O. O, Mattoso L and Martin-Neto L (2007) Detection of Brominated By-Products Using a Sensor Array Based on Nanostructured Thin Films of Conducting Polymers, Sensors, 10.3390/s7123258, 7:12, (3258-3271) Vol. 102, No. 6-7 January 1994Metrics About Article Metrics Publication History Originally published1 June 1994Published in print1 January 1994 Financial disclosuresPDF download License information EHP is an open-access journal published with support from the National Institute of Environmental Health Sciences, National Institutes of Health. All content is public domain unless otherwise noted. Note to readers with disabilities EHP strives to ensure that all journal content is accessible to all readers. However, some figures and Supplemental Material published in EHP articles may not conform to 508 standards due to the complexity of the information being presented. If you need assistance accessing journal content, please contact [email protected]. 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Determination of phthalate esters in sediment by accelerated solvent extraction and gas chromatography-triple quadrupole mass spectrometry

A method for the determination of seventeen phthalate esters in sediment by accelerated solvent extraction (ASE), gel-permeation chromatography (GPC) and gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS) has been developed. The target compounds were extracted at 100 degrees C and 103.4 MPa (1500 psi) by ASE using the mixtures of dichloromethane and acetone (1:1, v/v) as solvent. In order to eliminate the interferences from larger molecular sizes, the extract was purified at a flow rate of 5.0 mL/min by GPC. Following that, the extract was concentrated to a final volume of 1 mL exactly. The GC-MS/MS was applied to quantitative and qualitative analysis. Internal standard calibration approach was adopted, and the detection limits of seventeen phthalate esters ranging from 0.05 to 0.40 microg/kg were obtained. The correlation coefficients were beyond 0.996, the recoveries were from 50.5% to 107.9%, and the relative standard deviations were from 3.5% to 13.9%. Besides, the surrogate compounds spiked were used to monitor the performance of the method, and the recoveries were from 65.3% to 95.8% for the three surrogate compounds. The method is fast, sensitive and exact for analyzing seventeen phthalate esters simultaneously.

Determination of Chlorinated Dibenzo-p-Dioxins and Dibenzofurans in Various Materials

Determination of Chlorinated Dibenzo-p-Dioxins and Dibenzofurans in Various Materials

2081. Dioxane induction of nasal carcinomas

Nine N-nitrosamines (i.e., N-nitrosomethylamine, N-nitrosodiethylamine (NDEA), N-nitrosodimethylamine (NDMA), N-nitrosodi-n-propylamine (NDPA), N-nitrosomorpholine (NMor), N-nitrosopyrrolidine (NPyr), N-nitrosopiperidine (NPip), N-nitorosodi-n-butylamine (NDBA), and N-nitrosodiphenylamine (NDPhA) in atmospheric PM2.5 collected in the fall season from an roadside site and a residential in Seoul, Korea have been analyzed using a newly developed method consisting of simple direct liquid extraction assisted by ultrasonication and subsequent quantification using a gas chromatography-triple quadrupole mass spectrometry (GC-TQMS). Excellent recovery values (92–100%) and method detection limits for the target compounds atmospheric PM samples could be achieved even without an evaporation step for sample concentration. The concentration of total N-nitrosamines in PM2.5 was ranged from 0.3 to 9.4 ng m−3 in this study; NDMA, NDEA, NDBA, NPyr, and NMor in PM2.5 were found to be the most frequently encountered compounds at the sampling sites. Since no industrial plant is located in Seoul, vehicle exhausts were considered major cause of the formation of nitrosamines in this study. The mechanisms how these compounds are formed and detected in the atmosphere are explained from the viewpoint of secondary organic aerosol. Considering the concentrations of N-nitrosamines and their associated potential health risks, a systematic monitoring of nitrosamines present in both ambient air and PM2.5 including seasonal and diurnal variations of selected sites (including potential precursor sources) should be carried out in the future. The proposed sample pretreatment method along with the analytical method will definitely help us perform the monitoring study.