Measurement of nitrosamine and nitramine formation from NOx reactions with amines during amine-based carbon dioxide capture for postcombustion carbon sequestration.

With years of full-scale experience for precombustion CO(2) capture, amine-based technologies are emerging as the prime contender for postcombustion CO(2) capture. However, concerns for postcombustion applications have focused on the possible contamination of air or drinking water supplies downwind by potentially carcinogenic N-nitrosamines and N-nitramines released following their formation by NO(x) reactions with amines within the capture unit. Analytical methods for N-nitrosamines in drinking waters were adapted to measure specific N-nitrosamines and N-nitramines and total N-nitrosamines in solvent and washwater samples. The high levels of amines, aldehydes, and nitrite in these samples presented a risk for the artifactual formation of N-nitrosamines during sample storage or analysis. Application of a 30-fold molar excess of sulfamic acid to nitrite at pH 2 destroyed nitrite with no significant risk of artifactual nitrosation of amines. Analysis of aqueous morpholine solutions purged with different gas-phase NO and NO(2) concentrations indicated that N-nitrosamine formation generally exceeds N-nitramine formation. The total N-nitrosamine formation rate was at least an order of magnitude higher for the secondary amine piperazine (PZ) than for the primary amines 2-amino-2-methyl-1-propanol (AMP) and monoethanolamine (MEA) and the tertiary amine methyldiethanolamine (MDEA). Analysis of pilot washwater samples indicated a 59 µM total N-nitrosamine concentration for a system operated with a 25% AMP/15% PZ solvent, but only 0.73 µM for a 35% MEA solvent. Unfortunately, a greater fraction of the total N-nitrosamine signal was uncharacterized for the MEA-associated washwater. At a 0.73 µM total N-nitrosamine concentration, a ~25000-fold reduction in concentration is needed between washwater units and downwind drinking water supplies to meet proposed permit limits.

Quantification of dichloroiodomethane and bromochloroiodomethane in human blood by solid-phase microextraction coupled with gas chromatography-high-resolution mass spectrometry.

Iodine-containing trihalomethanes (iodo-THMs) are formed as disinfection byproducts when iodide-containing water is disinfected using chloramination process. Subsequent water use may lead to human exposure to iodo-THMs. Because of health concerns surrounding exposure to iodo-THMs, a rapid, reliable, and high-throughput analytical method was developed to quantify trace levels of two iodo-THMs: dichloroiodomethane (IDCM) and bromochloroiodomethane (IBCM) in human blood. These analytes from the headspace above blood samples were extracted using solid-phase microextraction. Analytes were then desorbed and separated by capillary gas chromatography and analyzed by high-resolution mass spectrometry with multiple ion monitoring. This method utilizes stable isotope dilution to quantify parts-per-trillion levels of all analytes, with excellent precision of < 9% coefficient of variation. At three spiked levels, method accuracy of IDCM and IBCM ranged between 6 and 20% difference when comparing spiked and measured amounts. The method limit of detection was 2 ng/L for both IDCM and IBCM. This selective, sensitive, and rapid method will help to assess human exposure to iodo-THMs and to study potential associations between exposure and adverse health outcomes.

Gene expression profiles for detecting and distinguishing potential endocrine-disrupting compounds in environmental samples.

Industrial and municipal processes may produce and release endocrine-disrupting compounds (EDCs) into the environment, but the exact nature of their effects is difficult to investigate. EDCs typically exert their effect by affecting gene expression aberrantly. To determine if gene expression profiles could be used to detect and distinguish estrogenic EDCs, an estrogen receptor positive human breast cancer cell line (MCF-7) was exposed to known estrogenic compounds, suspected EDCs, and extracts from three effluent samples. A set of specifically estrogen-regulated genes was identified by microarray analysis. Nine estrogen up-regulated genes (IGFBP4, HSPA8, B4GALT1, XBP1, KRT8, GTPBP4, HNRPAB, SLC2A1, and CALM1) and two estrogen down-regulated genes (ID2 and ZNF217) were consistently detectable in response to estrogen and other estrogenic compounds. Gene expression patterns in cells that were exposed to effluent sample extracts were compared to gene expression patterns in cells that were exposed to known endocrines. Using this technique, two of the effluent samples were shown to have estrogenic activity. This approach could easily be extended to screen for other types of receptor-mediated endocrine disruption. For example, cells expressing androgen or aryl hydrocarbon receptors could be used in gene expression profiling assays to detect androgenic effects or for the presence of bioactive aromatic hydrocarbons. Gene expression profiling is emerging as a sensitive and specific method to screen complex samples for endocrine disrupting activity.

A comparative evaluation of accelerated solvent extraction and Polytron extraction for quantification of lipids and extractable organochlorine in fish.

Optimal conditions for extraction methods using an accelerated solvent extractor (ASE) and a Polytron homogenizer were established for quantification of (crude) lipids and extractable organochlorine (EOCl) in fish. The two methods, an ASE consecutive extraction at 55 and 100 degrees C for ground, freeze-dried filets, and a Polytron extraction at room temperature with four repetitions for ground, wet filets and with two repetitions for wet fish livers were evaluated in terms of reproducibility and comparability. With respect to lipid measurement, the two methods have comparable reproducibility and the experimental errors are relatively small compared to natural variations of fish to fish within a sampling site. For EOCl measurement, the relative standard deviation tends to increase with decreasing levels of EOCl in specimens. An important factor for the relative standard deviation of measurements of analytes present at trace levels in fish matrices is sampling error in taking aliquots. Statistical analysis using a paired comparison design showed that measurement values (crude lipids or EOCl) obtained from these two extraction methods are, in general, not equivalent. There is a good correlation between the two methods for lipid measurement; whereas for EOCl measurements, high degrees of correlation exist within the exposed fish group, but not in the reference group.

Identification and confirmation of traces of chlorinated fatty acids in fish downstream of bleached kraft pulp mills by gas chromatography with halogen-specific detection.

Methyl esters of threo-9,10-dichlorooctadecanoic, threo-7,8-dichlorohexadecanoic, and threo-5,6-dichlorotetradecanoic acids, present in transesterified extracts of filets, gonad, intestinal fat and carcass of white sucker (Catostomus commersoni) sampled in receiving waters of bleached kraft pulp mill effluents, were identified by gas chromatography with halogen-specific detection (XSD). Identification was based on (1) a comparison of the retention times of a sample peak with a prospective reference standard on two stationary phases of very different polarities by spiking, and (2) elution behavior of configurational and positional isomers of dichloro fatty acid methyl esters.