GC/MS-Nontargetanalytik zur Aufklärung einer organischen Grundwasserkontamination. Teil I: Probennahme – Analytik – Identifikation der organischen Verbindungen

GC/MS Nontarget Analysis to Examine an Organic Groundwater Contamination. Part I: Sampling – Analysis – Identification GC/MS nontarget analysis is a combination of an extraction sequence and a GC/MS analysis without standards. The extraction sequence should enrich a wide range of organic substances with different chemical and physical properties. The GC/MS analysis without standards evaluates the total chromatogram whereas the possibilities of compound identification are limited. This kind of view is suited very well if the task of examinations are unknown organic contaminations and the conventional target analysis has to be expanded to a large number of compounds with the uncertainty of detecting the main contaminants. The extraction sequence is similar to the EPA 625 analysis of base/neutral and acid extractable organic compounds. Basis are liquid extraction and solid-phase extraction at different pH values. This extraction procedure covers approximately 30 % of total organic carbon of these groundwater samples from a contaminated area near a low temperature carbonization plant. Relevant groups of organic compounds analyzed in the contaminated groundwater or in the reference sample are substituted aromatics, phenols, benzoamines (anilines), and derivates of benzothiophene. Differences in the trace substance mixtures between the contaminated samples and the reference sample are demonstrated by applying modern graphical methods.     

Rapid Analysis of 1,4‐Dioxane in Groundwater by Frozen Micro‐Extraction with Gas Chromatography/Mass Spectrometry

An innovative micro‐extraction of aqueous samples coupled with gas chromatography/mass spectrometry in selected ion‐monitoring mode (GC/MS‐SIM) was developed to selectively analyze for 1,4‐dioxane with low part‐per‐billion detection sensitivity. Recoveries of 1,4‐dioxane ranged from 93% to 117% for both spiked laboratory reagent water and natural groundwater matrices, the later having elevated organic carbon content (8.34 ± 0.31 mg/L as total organic carbon). We observed that freezing the aqueous sample along with the extraction solvent enhanced the extraction efficiency, minimized physical interferences, and improved sensitivity resulting in a limit of detection for 1,4‐dioxane to approximately 1.6 μg/L. This method substantially reduces the labor, time, reagents and cost, and uses instruments that are commonly found in analytical laboratories. This method requires a relatively small sample volume (200 μL), and can be considered a green analytical method as it minimizes the use of toxic solvents and the associated laboratory wastes.     

Phytoscreening: A Comparison of In Planta Portable GC‐MS and In Vitro Analyses

Phytoscreening has been proven to rapidly delineate subsurface contaminant plumes for semiquantitative site assessment, with minimal impact to property or ecology through the collection and analysis of tree cores. Here, three phytoscreening methods were applied concurrently to identify multiple chlorinated volatile organic compounds (cVOCs) in a phytoremediation treatment system at a contaminated industrial facility. Tree coring, in planta gas chromatography–mass spectrometry (GC‐MS), and in planta passive sampling showed general agreement, with the in planta GC‐MS providing the quickest but least quantitative results. The portable GC‐MS sampling and analysis method identified six cVOCs in the xylem of hybrid poplars (Populus sp.) in the phytoremediation plot. These real‐time data can permit onsite identification and delineation of the contaminants, allowing for adaptive sampling during a single mobilization to a site. The in vitro methods provided quantitative data across two sampling campaigns, as relative cVOC concentrations remained similar between the two trips, despite a decrease in absolute cVOC concentrations from August to October. Overall, this research demonstrates the advantages and limitations of three phytoscreening techniques.     

Application of Dispersive Liquid–Liquid Microextraction Based on Solidification of Floating Organic Droplet Multi‐residue Method for the Simultaneous Determination of Polychlorinated Biphenyls,Organochlorine, and Pyrethroid Pesticides in Aqueous Sample

Dispersive liquid–liquid microextraction based on solidification of floating organic droplet (DLLME‐SFO) technique was successfully applied for simultaneous assay of eight polychlorinated biphenyls, two organochlorine, and four pyrethroid pesticides multi‐residue in aqueous samples by using GC‐electron capture detection. The effects of various parameters such as kind of extractant and dispersant and volume of them, extraction time, effect of salt addition, and pH were optimized. As a result, 5.0 µL 1‐dodecanol was chosen as extraction solvent, 600 µL methanol were used as dispersive solvent without salt addition, pH was adjusted to 7. Under the optimized conditions, the limits of detection (LOD) were ranged from 1.4 to 8.3 ng L^?1. Satisfactory linear range was observed from 5.0 to 2000 ng L^?1 with correlation coefficient better than 0.9909. Good precisions were also acquired with RSD better than 13.6% for all target analytes. The enrichment factors of the method were ranged from 786 to 1427. The method can be successfully applied to simultaneous separation and determination of three class residues in real water samples and good recoveries were obtained ranging from 76 to 130, 73 to 129, and 78 to 130% for tap water, lake water, and industrial waste water, respectively.     

Potential Occurrence of MTBE and BTEX in Groundwater Resources of Amman–Zarqa Basin,Jordan

This study investigates potential occurrence, distribution, and sources of the newly added gasoline oxygenate, methyl‐tert‐butyl ether (MTBE) and the petroleum derivatives benzene, toluene, ethylbenzene, and xylenes called collectively, BTEX, in Jordan's heavily populated Amman–Zarqa Basin (AZB). It presents the first data on the levels of MTBE and BTEX in the aquifers of this basin. One hundred and seventy‐nine (179) groundwater wells were sampled near petrol service stations, oil refinery storage tanks, car wrecks, bus stations, and chemical industries at different locations in the basin. Headspace GC and purge and trap GC–MS were utilized to determine the target substances in the samples. Concentrations of BTEX varied between no‐detection (minimum) for all of them to 6.6 µg/L (maximum) for ethylbenzene. MTBE was found in few samples but none has exceeded the regulated levels; its concentrations ranged between no‐detection to 4.1 µg/L. However, though the contamination levels are very low they should be considered alarming.     

Chemical speciation of polycyclic aromatic hydrocarbons in sediments: Partitioning and extraction of humic substances

The primary objective of this study was to examine the chemical speciation of polycyclic aromatic hydrocarbons (PAHs) found in sediments endowed with different characteristics. To achieve this purpose and because the nature of the sediments influences the distribution of PAHs, we have analyzed four different types of sediments. To study the role of organic matter in the sequestration of PAHs, we fractionated humic substances into humic acids and humin-mineral fractions. After their separation and purification, the humic components were examined for their sorptive reactivity by extracting them with organic solvents; these extracts were subsequently subjected to GC/MS analysis. Our results show that PAHs are distributed between labile and sequestered fractions in sediments. A slower uptake of PAHs occurs when the sequestered fraction is formed, and this process can be prolonged and may be influenced by the characteristics if the sediment. Our study suggests that organic contaminants are available in muddy sediments for a longer period of time than in sandy sediments.     

Nature and Estimated Human Toxicity of Polar Metabolite Mixtures in Groundwater Quantified as TPHd/DRO at Biodegrading Fuel Release Sites

Polar metabolites resulting from petroleum biodegradation are measured in groundwater samples as TPHd unless a silica gel cleanup (SGC) is used on the sample extract to isolate hydrocarbons. Even though the metabolites can be the vast majority of the dissolved organics present in groundwater, SGC has been inconsistently applied because of regulatory concern about the nature and toxicity of the metabolites. A two‐step approach was used to identify polar compounds that were measured as TPHd in groundwater extracts at five sites with biodegrading fuel sources. First, gas chromatography with mass spectrometry (GC‐MS) was used to identify and quantify 57 individual target polar metabolites. Only one of these compounds—dodecanoic acid, which has low potential human toxicity—was detected. Second, nontargeted analysis was used to identify as many polar metabolites as possible using both GC‐MS and GC×GC‐MS. The nontargeted analysis revealed that the mixture of polar metabolites identified in groundwater source areas at these five sites is composed of approximately equal average percentages of organic acids, alcohols and ketones, with few phenols and aldehydes. The mixture identified in downgradient areas at these five sites is dominated by acids, with fewer alcohols, far fewer ketones, and very few aldehydes and phenols. A ranking system consistent with systems used by USEPA and the United Nations was developed for evaluating the potential chronic oral toxicity to humans of the different classes of identified polar metabolites. The vast majority of the identified polar metabolites have a “Low” toxicity profile, and the mixture of identified polar metabolites present in groundwater extracts at these five sites is unlikely to present a significant risk to human health.     

Gaschromatographische Spurenanalyse von leichtflüchtigen Halogenkohlenwasserstoffen in Wässern mittels simultaner ECD/FID-Detektion

The substances which are expulsed from the water sample by a nitrogen current are first adsorbed on a column filled with Tenax GC and subsequently expulsed at 200° and fed into the gas-chromatographic column. The parallel detection improves the identification of individual substances and makes the detection of aromatics possible at the same time. Characteristics of the process (detection limit, standard deviation, coefficient of variation, rate of retrieval) are determined and examples of analysis are given. For a water sample of 10 ml the detection limit lies at or below 1 μg/l.     

Simultaneous Analysis of Natural Free Estrogens and Their Conjugates in Wastewater by GC‐MS

A solid‐phase extraction (SPE)‐gas chromatography (GC)‐mass spectrometry (MS) analytical method was developed for the simultaneous analysis of natural free estrogens and their conjugates in wastewater samples. Natural free estrogens and their conjugates in wastewater were successfully separated by the oasis hydrophilic‐lipophilic balance solid phase extraction (Oasis HLB SPE) method, and the conjugates were initially enzyme hydrolyzed by β‐glucuronidase or arylsulfatase from Helix pomatia prior to derivatization. N‐methyl‐N‐(tert‐butyldimethylsilyl)trifluoroacetamide (MTBSTFA) plus 1% tert‐butyldimetheylchlorosilane (TBDMCS) was chosen as the derivatization reagent, and the most appropriate conditions of derivatization were determined to be at 95°C for 90 min. The recovery ratios of nine target chemicals were determined by spiking them in 1 L of ultra‐purified water or the influent of a wastewater treatment plant (WWTP). The recovery ratios of six out of nine for the analytes ranged from 73.3–114.9% with relative standard deviations (RSD) from 1.6–19.9%. The established method was successfully applied to environmental wastewater samples which were collected from one municipal wastewater treatment plant (WWTP) in Osaka, Japan, for the determination of natural free estrogens and their conjugates. In the influent sample, E1, E2, E1‐3S, E3‐3S, and E1‐3G were detected at concentrations of 16.6, 9.6, 8.2, 21.9, and 3.2 ng L^–1, respectively. However, only E1 was detected at a high concentration of 44 ng L^–1 in the effluent sample, suggesting that it is the dominant natural free estrogen in the effluent.     

Bestimmung von Organochlorpestiziden in Schlämmen und Sedimenten

A method for the determination of organohalogens by gas chromatography using electron capture (EDC) and mass-spectrometric (MS) detection was developed for sediments from lakes and sludges of water treatment plants. The method was described and separate techniques for sample preparation were investigated to compare the retrieval rates and the best approach to the “real value”. With the help of solid-liquid-phase- and liquid-liquid-phase extraction sulphur, most of the organosulphur compounds and carbon acids were effectively removed. The compounds were identified by comparing temperature programmed retention indices with those of reference compounds and by high-resolution GC/MS.     

Speciation of Arsenic Using Chelation Solvent Extraction and High Performance Liquid Chromatography

Research interest in speciation of arsenic stems from its species dependent behavior in the environment and in living organisms. The complexity of the matrix to be analyzed and low concentrations of target arsenic species that may be labile or difficult to chromatogram, indicate that a suitable pre‐treatment methodology is required. This study investigated the usefulness of chelation solvent extraction – high performance liquid chromatography (CSE‐HPLC) for the speciation of arsenic in water. It involved reacting arsenic with the chelant known for its affinity towards arsenic, followed by extraction, separation, and identification of the arsenic‐chelant‐arsenic complex. Arsenic species having different physicochemical properties were investigated. Species, such as, As₂O₃, As₃O₅, KH₂AsO₄, Na₂HAsO₄, and NaAsO₂ were detected as a group of closely eluted peaks with different retention times and spectral properties, whereas, the organic arsenic species CH₃Na₂AsO₃, o‐arsanilic acid, roxarson and triphenyl arsine separated quite well on the EnviroseP‐CM HPLC column. Key method parameters, such as, type of HPLC column, composition of mobile phase and organic solvents affecting peak resolution and sensitivity were optimized. Real environmental matrices contaminated with arsenic were analyzed under varying wavelengths (λ_max = 190, 210, 220, 234, 244, and 282 nm), with good precision. Different arsenic species were detected in these samples with excellent background and signal‐to‐noise ratios demonstrating the robustness of the method. The detection limit, reproducibility, selectivity, accuracy, and dynamic range of the calibration curves were evaluated.     

Degradation of Coking Wastewater under Microwave Irradiation in the Presence of Modified Activated Carbon

In this study, a new material consisting of activated‐carbon‐containing magnetic oxide is prepared for assisted microwave (MW) irradiation treatment of coking wastewater. The optimum condition for degrading coking wastewater is 98.14% chemical oxygen demand (COD), under which 87.57% ammonia nitrogen (NH₃–N) can be removed. The results are verified by GC–MS, showing that most organic pollutants can be adsorbed by modified activated carbon (MAC). The surface morphology and elemental composition of MAC before and after microwave irradiation and adsorption is determined by scanning electron microscopy. After microwave irradiation, many apertures of pores looked relatively large. It can be shown that MAC as a catalyst in the microwave‐assisted treatment process has many advantages, including rapid degradation of COD and NH₃–N. In conclusion, microwave‐irradiation‐assisted MAC treatment of coking wastewater is a novel technology that is economical, efficient, and has broad prospects for development.     

Einsatz eines Immunoassays als Screening-Verfahren für die Untersuchung von Grundwasserproben auf Mecoprop

Application of an Enzyme Immunoassay for the Detection of Mecoprop in a Ground water Screening Procedure A competitive solid-phase enzyme immunoassay based on rabbit polyclonal antibodies was tested for its reliability. This assay, used for the detection of the phenoxycarboxylic acid mecoprop [2-(4-chloro-2-methylphenoxy-)propionic acid], has already been characterized in terms of middle of the test (0.36 μg/L at 50% B/B₀) and detection limit (0.06 μg/L at 80% B/B₀) by Weber (Acta hydrochim. hydrobiol. 22, 53–59 (1994)). For the reliability test, a small number from a batch of one hundred groundwater samples were spiked. The analyst was neither aware of which nor of how many samples were spiked. The spiked samples were all detected as positive. There were no false negative results. From these findings, values of 1 were obtained for the diagnostic sensitivity and for the diagnostic specificity. Based on these results, the mecoprop contents of 228 groundwater samples from various waterlevel gauges of a test field were determined. The test site had previously been treated repeatedly with this herbicide. Confirmation of the enzyme immunoassay results was carried out by GC/MS. This showed that the enzyme immunoassay gave one false positive result only. All other results from immunoassay and GC/MS showed good correlation.     

Anodic Oxidation as Green Alternative for Removing Diethyl Phthalate from Wastewater Using Pb/PbO2 and Ti/SnO2 Anodes

The electrochemical oxidation (EO) of diethyl phthalate (DEP) in aqueous solution was studied at Pb/PbO₂ and Ti/SnO₂ anode materials under galvanostatic‐experimental conditions. Results obtained clearly demonstrated that the anode plays a significant role for the optimization of the oxidation process, deciding the mechanisms and by‐products formed. DEP and by‐products of oxidation were also analyzed during various stages of the electrolysis reaction by HPLC and GC/MS techniques. Before the analysis by GC/MS technique, the samples were treated by solid phase microextraction (SPME) in order to concentrate the compounds from the reaction solution and identify all electrolysis intermediates. Current efficiencies (instantaneous current efficiency; ICE and total current efficiency; TCE) achieved during EO experiments were dependent on anode used and current density (20–40 mA cm^?2) at 40°C. The results obtained demonstrated that the environmental electrochemical methods can be a feasible alternative for the wastewater treatment containing hazardous phthalates.     

Portable GC/MS Methods to Evaluate Sources of cVOC Contamination in Indoor Air

A portable gas chromatograph‐mass spectrometer (GC/MS) was used to investigate sources of chlorinated volatile organic compound (cVOC) contamination in indoor air at 46 residences around Hill AFB, Utah, that were potentially affected by vapor intrusion. Analytical methods were developed to allow sample turnaround times of less than 10 min and method detection limits (MDLs) generally less than 1 μg/m³ for a selected list of cVOCs. Area‐by‐area sampling was used to identify the likely vapor source locations. In many cases, individual container/enclosure sampling and subsequent field emission rate measurements from isolated consumer products were used to determine if identified products were likely to be the primary source of vapors in the residence. The portable GC/MS was also used to characterize vapor intrusion in two residences. In one of these two residences, building pressure control was used to enhance vapor entry in order to facilitate the investigation resulting in confirmation of vapor intrusion and identification of a primary route of vapor entry. cVOCs were identified in 42 of the 46 homes investigated, subsurface vapor intrusion was identified in two homes, and two homes had inconclusive results.     

The contribution of bacteria to organic matter in coal-measure source rocks

On the basis of GC–MS analysis, a suite of nine coal-measure source rocks(Ro 0.51%–0.63%) from the southern margin of Junggar basin was found to contain many biomarkers for bacterially-generated hydrocarbons:hopane, sesquiterpene, C₂₃+ monomethyl alkanes(even carbon predominance), and C₂₄+ alkyl cyclohexane.Rock–eval and microscope analysis indicate that vitrinite(especially desmocollinite and homocollinite) plays a significant role in the generation of hydrocarbons in coalmeasure source rocks. Vitrinite performs this role by absorbing ultramicroscopic organic matter, generally in the form of resins or bacterial plastids. C₂₃+ monomethyl alkanes(even carbon predominance) and C₂₄+ alkyl cyclohexane series compounds are derived from bacterial metabolites of higher plants. The ultramicro organic matter adsorbed by vitrinite source rocks in the study area is probably ultramicro bacterial plastids. Because the organic matter of higher plants with low hydrogen content has been transformed into organic matter rich in hydrogen by bacteria, the hydrocarbon generation capacity of source rocks is greatly improved. In other words, in coal-measure source rocks, bacteria play an important role in hydrocarbon generation.     

Simultaneous Analysis of Natural Free Estrogens and Their Sulfate Conjugates in Wastewater

Natural estrogens from humans increasingly attract attention because of their strong endocrine disrupting potency. The discharge of sewage water is considered as the most important source of these endocrine disrupting chemicals (EDCs) in the environment. Therefore, a GC‐MS method was developed for the simultaneous analysis of six natural free estrogens and their sulfate conjugates in municipal wastewater, in which natural free estrogens and sulfate conjugates were successfully separated from an Oasis HLB solid phase extraction (SPE) cartridge with two different eluents, and the sulfate conjugates were then transformed to their corresponding free estrogens by acid solvolysis. Before the analysis with GC‐MS, samples were derivatized by N,O‐bis (trimethylsilyl) trifluoroacetamide (BSTFA) plus 1% trimethylchlorosilane (TMCS) at 80°C for 40 min. Satisfactory recoveries ranging from 64 to 112.3% were obtained by spiking ultra‐purified water, raw, and treated municipal wastewater with the six estrogens at 50, 100, and 50 ng/L, respectively. The method was successfully applied to wastewater samples from one WWTP, which suggested that E1 was the dominant natural estrogens in effluent and E3‐3S was one of the conjugates possibly occurring in the effluent.     

Removal of Nitro Aromatic Compounds from 2,4,6‐Trinitrotoluene Red Water Using 1,2‐Ethanediamine Modified Macroporous Polystyrene Microspheres

To remove nitro aromatic compounds (NACs) from 2,4,6‐trinitrotoluene (TNT) red water, large‐pore‐size (pore size = 200 nm) polystyrene (PSt) microspheres were activated with chloroacetyl chloride followed by reaction with 1,2‐ethanediamine (EDA). Fourier transform IR analyses showed that the amino group was introduced onto PSt microspheres. Determination of the total amino group and primary amino densities suggested that the imino group was the functional group of EDA–PSt. Scanning electron microscope images and mercury porosimetry measurements indicated that the pore structure was well maintained during the reaction. After adsorption with EDA–PSt, 98.5% chemical oxygen demand and 99% acute toxicity of TNT red water was removed. As shown by HPLC and GC–MS, all the neutral and acid NACs in TNT red water were removed by EDA–PSt, while the basic NACs were not. The results showed that hydrogen bonding and electrostatic attraction were involved in adsorption. The adsorbed neutral and acid NACs were eluted using methanol and 0.1 mol L^?1 NaOH, respectively.     

Determination of Selected Endocrine Disrupter Compounds at Trace Levels in Sewage Sludge Samples

Simultaneous determination of endocrine disrupter compounds (EDCs), namely diltiazem, progesterone, benzylbutylphthalate (BBP), estrone, and carbamazepine (Cbz) were performed by using high performance LC–electrospray tandem MS. The ultrasound‐aided sequential extraction of sludge samples was optimized to increase extraction efficiencies of the analytes; ranging between 93.0–98.3% recovery. The limit of detection values for diltiazem, progesterone, BBP, estrone, and Cbz were found as 0.78, 0.72, 0.24, 0.75, and 0.72 µg/kg, respectively. Sludge samples taken from Ankara Tatlar; Hurma, Lara and Kemer of Antalya, and Middle East Technical University‐vacuum rotating membrane wastewater treatment plant (WWTP) aeration tanks were analyzed for their EDCs contents under optimized conditions. Diltiazem was found in all the samples in the range between 116.4–180.8 ng/g while progesterone and estrone were not detected in any of the samples analyzed with the exception of Tatlar WWTP. The BBP concentration was between beyond detection and 9195.5 ng/g. In addition, Cbz was found in all the samples ranging from 25.6 to 118.8 ng/g.     

Estimation of Organic Pesticide Residues in Wines of Moldova

This paper presents the study of pesticide residues in Moldovan wine products originating from traditional agriculture because the appreciation of these compounds is an important aspect of food safety. During 2007–2010, about 3000 analyses of wine samples using GC‐MS were investigated. Persistent organic pollutants (POPs), i.e., α‐, β‐, γ‐HCH, aldrine, and heptachlor were not found in any of the samples. Insignificant quantities of metalaxyl and mefenoxam were found in some wine samples. The missing of POPs in wine products represents an important quality feature. The study showed that if growers comply with rules of phytosanitary treatments and the waiting period is respected, the content of pesticide residues can be reduced to safe limits. Also, the list of approved pesticides must be regularly revised, taking into account the degree of toxicity. Additionally, growers are to be constantly informed about effectuated changes.