Determination of phosphoric acid mono- and diesters in municipal wastewater by solid-phase extraction and ion-pair liquid chromatography-tandem mass spectrometry

The first analytical method for the determination of 13 phosphoric acid mono- and diesters from aqueous samples is presented. The method consists of solid-phase extraction (SPE) and ion-pair liquid chromatographic separation with tri-n-butylamine coupled to electrospray ionization tandem mass spectrometry in the negative ion mode. Due to a lack of pure standards, only 3 of the 13 esters could be quantified. SPE recoveries ranged from 71 to 112% for di-n-butyl phosphate, diphenyl phosphate, and di-(2-ethylhexyl) phosphate (DEHP) with limits of quantification from 7 to 14 ng/L for 100-mL samples. At analyte concentrations >or=1 microg/L, aqueous samples can be analyzed by direct injection without extraction. In municipal wastewater, six diesters and one monoester were unambiguously identified by comparison with synthesized reference material. DEHP showed highest concentrations of 60 and 5 microg/L in raw and treated wastewater, respectively. The detection of monoethylhexyl phosphate was confirmed by LC-Q-TOF-MS analysis, and it was found at a concentration level comparable to DEHP. Laboratory degradation tests show that phosphoric acid diesters can be formed as intermediates in the microbial degradation of trialkyl phosphates that are being used as flame retardants and plasticizers.     

Multiclass determination of sunscreen chemicals in water samples by liquid chromatography-tandem mass spectrometry

A novel analytical method based on solid-phase extraction (SPE) and liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) for the determination of UV sunscreen agents in the water environment is presented. After a thorough investigation of SPE and LC-MS/MS conditions, it permits the enrichment and determination of nine of these compounds in a single methodology, including three very polar sulfonates (e.g., 2-phenylbenzimidazole-5-sulfonic acid, PBSA) and six other less polar compounds (e.g., benzophenone-3, BP-3; octocrylene, OC,...). Other important matters of concern in the determination of UV filters at trace levels in water, i.e., adsorption on glassware and blank contamination problems, have also been discussed and minimized. This methodology affords detection limits between 7 and 46 ng L-1 and SPE recoveries in the range 63-102% from different real water matrixes, except for butylmethoxydibenzoylmethane (BM-DBM), which was not determinable in wastewater samples due to adsorption problems. The application of the method allowed reporting the levels of benzophenone-4 (BP-4) in environmental water samples for the first time, where it was identified as one of the most important in concentration among the UV filters studied, particularly in wastewater (237-1481 ng L-1).     

Determination of benzotriazole corrosion inhibitors from aqueous environmental samples by liquid chromatography-electrospray ionization-tandem mass spectrometry

The first method for the determination of commonly used corrosion inhibitors in environmental water samples by liquid chromatography-electrospray ionization-tandem mass spectrometry is presented. Benzotriazole (BTri) and the two isomers of tolyltriazole (5- and 4-TTri) are separated in an isocratic run. By gradient elution, BTri, 4-TTri, 5-TTri, and xylyltriazole can be determined simultaneously with three benzothiazoles, but here TTri isomers coelute. The instrumental detection limit of 2 pg allows the determination of the three most important benzotriazoles from municipal wastewater and most surface waters by direct injection into the HPLC system without previous enrichment. When solid-phase extraction is employed with mean recovery rates of 95-113%, the limit of quantification for benzotriazoles range from 10 ng/L in groundwater to 25 ng/L in untreated wastewater. BTri and TTri were determined in municipal wastewater in microgram per liter concentrations. Elimination in wastewater treatment appears to be poor, and BTri and TTri can be followed through a water cycle from treated municipal wastewater through surface water to bank filtrate used for drinking water production. The TTri isomers show markedly different biodegradation behavior with 4-TTri being more stable.     

Liquid chromatography-tandem mass spectrometry application, for the determination of extracellular hepatotoxins in Irish lake and drinking waters

A novel method for the determination of hepatotoxins; microcystins (MCs), and nodularin (Nod) in lake water and domestic chlorinated tap water has been developed using liquid chromatography hyphenated with electrospray ionization triple quadrupole mass spectrometry (LC-ESI-MS/MS). Optimization of the mass spectrometer parameters and mobile-phase composition was performed to maximize the sensitivity and reproducibility of the method. Detection of the hepatotoxins was carried out using multiple reaction monitoring experiments, thus improving the selectivity of the method. A total ion chromatogram and a precursor ion scan on ion m/z 135 was also applied to all samples to detect unknown microcystins or microcystins for which there are no standards available. A comprehensive validation of the LC-ESI-MS/MS method was completed that took into account matrix effects, specificity, linearity, accuracy, and precision. Good linear calibrations were obtained for MC-LR (1-200 microg/L; R2=0.9994) in spiked lake and tap water samples (1-50 microg/L; R2=0.9974). Acceptable interday repeatability was achieved for MC-LR in lake water with RSD values (n=9) ranging from 9.9 (10 microg/L) to 5.1% (100 microg/L). Excellent limits of detection (LOD) and limits of quantitation (LOQ) were achieved with spiked MCs and Nod samples; LOD=0.27 microg/L and LOQ=0.90 microg/L for MC-LR in the "normal linear range" and LOD=0.08 microg/L and LOQ=0.25 microg/L in the "low linear range" in both lake and chlorinated tap water. Similar results were obtained for a suite of microcystins and nodularin. This sensitive and rapid method does not require any sample preconcentration, including the elimination of solid-phase extraction (SPE) for the effective screening of hepatotoxins in water below the 1 microg/L WHO provisional guideline limit for MC-LR. Furthermore, SPE techniques are time-consuming, nonreproducible at trace levels, and offer poor recoveries with chlorinated water. The application of this LC-ESI-MS/MS method for routine screening of hepatotoxins in lake and chlorinated tap water (average Cl2=0.23 mg/L) is achieved and this study represents the first direct method for the screening of hepatotoxins in chlorinated tap water.     

Application of porous membrane-protected micro-solid-phase extraction combined with HPLC for the analysis of acidic drugs in wastewater

This report describes the use of a porous membrane-protected micro-solid-phase extraction (micro-SPE) procedure to extract acidic drugs from wastewater that are then determined by high-performance liquid chromatography with ultraviolet detection. The micro-SPE device consists of C18 sorbent held within a membrane envelope made of polypropylene. Ketoprofen and ibuprofen were selected as model compounds, and extraction parameters were optimized. Correlation coefficients of 0.9980 and 0.9953 were obtained for ketoprofen and ibuprofen, respectively, across a concentration range of 1-250 microg/L. Relative extraction recoveries were between 94 and 112%. The relative standard deviation of the analytical method ranged between 2 and 10%, respectively. The method detection limits for these target analytes in wastewater ranged from 0.03 to 0.08 microg/L. When compared to conventional solid-phase extraction (SPE), this new method showed better detection limits with good reproducibility. The results shows that this micro-SPE technique is a feasible alternative to multistep SPE for the extraction of analytes in complex samples.     

Simultaneous analysis of multiple classes of antibiotics by ion trap LC/MS/MS for assessing surface water and groundwater contamination

Solid-phase extraction (SPE) and liquid chromatography in combination with ion trap mass spectrometry (LC/MS/MS) conditions were optimized for the simultaneous analysis of 13 antibiotics belonging to multiple classes and caffeine in 3 different water matrixes. The single-cartridge extraction step was developed using a reversed-phase cartridge, resulting in recoveries for the 14 compounds ranging from 71 to 119% with relative standard deviations of 16% or lower. The analytes were separated in one chromatographic run, and the SPE-LC/MS/MS detection limits ranged from 0.03 to 0.19 microg/L. The SPE procedure was validated in groundwater, surface water, and wastewater. The analysis of samples from each of the three water matrixes revealed clindamycin (1.1 microg/L) in surface water and multiple antibiotics in wastewater (0.10-1.3 microg/L). The use of identification points to unambiguously assign the identity of antibiotics in various water matrixes was applied to an ion trap data-dependent scanning method, which simultaneously collects full scan and full scan MS/MS data for the unequivocal identification of target analytes.     

Low part per trillion determination of reactive alkanethiols in wastewater by in situ derivatization-solid-phase microextraction followed by GC/MS

A solid-phase microextraction (SPME) procedure for the simultaneous determination of volatile alkanethiols (i.e., methane-, ethane-, propanethiol) and dihydrogen sulfide in aqueous samples as stable thioethers followed by GC/MS determination was developed. Accordingly, N-ethylmaleimide as derivatization reagent in the aqueous phase was used for the first time, improving the analyte stability and method sensitivity in comparison to the determination of free forms. Thus, pH of the aqueous medium, reaction time, and derivatization reagent concentration have been evaluated, and the main parameters affecting the SPME process (i.e., coating selection, extraction mode and time profile, extraction and desorption temperatures) optimized. At the selected derivatization and extraction conditions, the proposed method provided no matrix effect either in the derivatization reaction or in the microextraction steps. RSD values were lower than 11% and LODs from 0.74 to 5.2 ng L(-1). The developed procedure was successfully applied to different water and wastewater samples, where dihydrogen sulfide and some of the target alkanethiols were identified at low-microgram per liter concentrations.     

Trace analysis of antidepressant pharmaceuticals and their select degradates in aquatic matrixes by LC/ESI/MS/MS

Treated wastewater effluent is a potential environmental point source for antidepressant pharmaceuticals. A quantitative method was developed for the determination of trace levels of antidepressants in environmental aquatic matrixes using solid-phase extraction coupled with liquid chromatography-electrospray ionization tandem mass spectrometry. Recoveries of parent antidepressants from matrix spiking experiments for the individual antidepressants ranged from 72 to 118% at low concentrations (0.5 ng/L) and 70 to 118% at high concentrations (100 ng/L) for the solid-phase extraction method. Method detection limits for the individual antidepressant compounds ranged from 0.19 to 0.45 ng/L. The method was applied to wastewater effluent and samples collected from a wastewater-dominated stream. Venlafaxine was the predominant antidepressant observed in wastewater and river water samples. Individual antidepressant concentrations found in the wastewater effluent ranged from 3 (duloxetine) to 2190 ng/L (venlafaxine), whereas individual concentrations in the waste-dominated stream ranged from 0.72 (norfluoxetine) to 1310 ng/L (venlafaxine).     

Membrane-assisted solvent extraction of triazines, organochlorine, and organophosphorus compounds in complex samples combined with large-volume injection-gas chromatography/mass spectrometric detection

The performance of the fully automated membrane-assisted solvent extraction was investigated for 47 environmental contaminants (among them 30 organochlorine compounds, 9 organophosphorus compounds, and 7 triazines). The extraction took place in a 20-mL headspace vial filled with the aqueous sample and containing a polypropylene membrane bag with 1 mL of cyclohexane as extractant. This device was handled by a multipurpose sampler, which enabled the sample to be mixed at a defined temperature with subsequent large-volume injection of the organic extract taken out of the membrane bag. After optimization of extraction parameters, the method was validated for the three compound classes, triazines and organochlorine and organophosphorus compounds, using spiked distilled water. Then, the extraction yield of these analytes from several complex samples such as a natural and a synthetic wastewater, a bacterial culture, and orange juice was determined and compared to a conventional liquid-liquid extraction. Furthermore, the possibility of reducing matrix interference by adding salt, methanol, or detergent during membrane-assisted solvent extraction was investigated.     

Analysis of endocrine disruptors, pharmaceuticals, and personal care products in water using liquid chromatography/tandem mass spectrometry

A method has been developed for the trace analysis of 27 compounds from a diverse group of pharmaceuticals, steroids, pesticides, and personal care products. The method employs solid-phase extraction (SPE) and liquid chromatography/tandem mass spectrometry (LC/MS/MS), using electrospray ionization (ESI) in both positive and negative modes and atmospheric pressure chemical ionization in positive mode. Unlike many previous methods, a single SPE procedure using 1 L of water coupled to a simple LC method is used for all ionization modes. Instrument detection limits for most compounds were below 1.0 pg on column with reporting limits of 1.0 ng/L in water. Recoveries for most compounds in deionized water were greater than 80%. Sulfuric acid was found to be the preferred sample preservative, and structures of all MS/MS product ions are proposed. Matrix effects from waters with a high content of treated municipal effluent were observed in both ESI modes and are discussed in the paper.     

Trace determination of macrolide and sulfonamide antimicrobials, a human sulfonamide metabolite, and trimethoprim in wastewater using liquid chromatography coupled to electrospray tandem mass spectrometry

An analytical method has been developed and validated for the simultaneous trace determination of four macrolide antibiotics, six sulfonamides, the human metabolite N4-acetylsulfamethoxazole, and trimethoprim in wastewater. The method was validated for tertiary, secondary, and-unlike in previously published methods-also for primary effluents of municipal wastewater treatment plants. This wide range of application is necessary to thoroughly investigate the occurrence and fate of chemicals in wastewater treatment. Wastewater samples were enriched by solid-phase extraction, followed by reversed-phase liquid chromatography coupled to tandem mass spectrometry using positive electrospray ionization. Recoveries from all sample matrixes were generally above 80%, and the combined measurement uncertainty varied between 2 and 18%. Concentrations measured in tertiary effluents ranged between 10 ng/L for roxithromycin and 423 ng/L for sulfamethoxazole. Corresponding levels in primary effluents varied from 22 to 1450 ng/L, respectively. Trace amounts of these emerging contaminants reach ambient waters, since all analytes were not fully eliminated during conventional activated sludge treatment followed by sand filtration. In the case of sulfamethoxazole, the amount present as human metabolite N4-acetylsulfamethoxazole had to be taken into account in order to correctly assess the fate of sulfamethoxazole in wastewater treatment.     

Determination of perfluorinated surfactants in surface water samples by two independent analytical techniques: liquid chromatography/tandem mass spectrometry and 19F NMR

Perfluorinated surfactants are an important class of specialty chemicals that have received recent attention as a result of their persistence in the environment. Two analytical methods for the determination of perfluorinated surfactants in aqueous samples were developed in order to investigate a spill of 22000 L of fire retardant foam containing perfluorinated surfactants into Etobicoke Creek (Toronto, Ontario). With the first method, aliquots of surface water (0.2-200 mL) were preconcentrated using solid-phase extraction. Liquid chromatography/tandem mass spectrometry was employed for identification and quantification of each perfluorinated surfactant. Total perfluorinated surfactant concentrations in surface water samples ranged from 0.011 to 2270 microg/L, and perfluorooctanesulfonate was the predominant surfactant observed. Interestingly, perfluorooctanoate was detected in surface water sampled upstream of the spill. A second method employing 19F NMR was developed for the determination of total perfluorinated surfactant concentrations in aqueous samples (2-100 mL). By 19F NMR, the surface water concentrations ranged from nondetect (method detection limit, 10 microg/L for a 100-mL sample) to 17000 microg/L. These methods permit comprehensive evaluation of aqueous samples for the presence of perfluorinated surfactants and have applicability to other sample matrixes.     

燃烧裂解-离子色谱法测定工业废水中的可吸附有机卤素

可吸附有机卤素(AOX)是用来表征水体有机卤化物污染程度的有效指标.有机卤化物的广泛应用还会增加工业废水中AOX的残留水平,而有机卤化物往往具有高的毒性,因此需要重视工业废水中AOX的污染水平.AOX包括可吸附有机氯(AOCl)、可吸附有机溴(AOBr)和可吸附有机碘(AOI).该研究建立燃烧裂解-离子色谱法测定工业废...     

Determination of carbamazepine and its metabolites in aqueous samples using liquid chromatography-electrospray tandem mass spectrometry

A quantitative method is described for solid-phase extraction (SPE) followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the simultaneous analysis of carbamazepine and its five metabolites, 10,11-dihydro-10,11-epoxycarbamazepine, 10,11-dihydro-10,11-dihydroxycarbamazepine, 2-hydroxycarbamazepine, 3-hydroxycarbamazepine, and 10,11-dihydro-10-hydroxycarbamazepine. An SPE procedure was used to concentrate target compounds from aqueous samples collected from sewage treatment plant (STP) wastewater and surface water. Extracts were analyzed using electrospray LC-MS/MS with time-scheduled selected reaction monitoring. The recoveries of the analytes were 83.6-102.2% from untreated sewage (influent), 90.6-103.5% from treated sewage (effluent), and 95.7-102.9% from surface water samples. The instrumental detection limits were 0.8-4.8 pg for the analytes. Matrix effects were investigated for the analytes in HPLC-grade water, surface water, and STP influent and effluent. Ion suppression increased for analytes in order of surface water to STP effluent to STP influent, but no ion suppression was observed for analytes in HPLC-grade water. The developed method was validated by analysis of environmental aqueous samples: STP influent and effluent and surface water. Carbamazepine and all five metabolites were detected in STP influent and effluent samples. Only carbamazepine and 10,11-dihydro-10,11-dihydroxycarbamazepine were detected in the surface water sample. Notably, 10,11-dihydro-10,11-dihydroxycarbamazepine was detected at approximately 3 times higher concentrations than the parent drug, carbamazepine, in all of the aqueous samples. To our knowledge, this is the first report on the simultaneous determination of carbamazepine and its metabolites in environmental samples.     

Simultaneous HPLC determination of peroxyacetic Acid and hydrogen peroxide

The first instrumental method for simultaneous determination of peroxyacetic acid (PAA) and hydrogen peroxide has been developed. The successive quantitative reaction of PAA with methyl p-tolyl sulfide (MTS) and hydrogen peroxide with triphenylphosphine (TPP) yields the corresponding sulfoxide MTSO and phosphine oxide TPPO. The reagents and their oxides are separated by HPLC on reversed-phase columns with acetonitrile/water gradient elution within 5 min. External calibration with the solid standards of MTSO and TPPO leads to a very accurate and reliable method. Samples are stable and can be stored after derivatization for several days prior to analysis. Real samples from brewery disinfection were analyzed in comparison to titration with excellent correlation.     

Evaluation and optimization of an on-line admicelle-based extraction-liquid chromatography approach for the analysis of ionic organic compounds

Admicelles-based solid-phase extraction (SPE) was on-line coupled with liquid chromatography/electrospray ionization/ion trap mass spectrometry, and it was proposed for the extraction of ionic organic compounds based on the formation of surfactant-analyte ion pairs. The approach was illustrated by studying the preconcentration of quaternary ammonium herbicides (quats) on sodium dodecyl sulfate (SDS) admicelles produced on alumina. Optimization of the parameters affecting SPE were studied on the basis that admicelles are dynamic entities in equilibrium with the aqueous phase. Some general guidelines could be established for method development from the results obtained. Factors influencing on-line operation were elucidated. On-line regeneration of the sorbent in each run was easily achieved by disruption of SDS admicelles with methanol and posterior coating of the alumina with SDS. The recovery of quats from drinking water samples were found quantitative for paraquat, diquat, and difenzoquat and above to 70% for chlormequat and mepiquat. Concentration factors of about 250, using sample volumes of 50 mL, were achieved. The detection limits ranged from 10 to 30 ng/L. The approach developed permits compliance with the directives of the European Community for drinking waters (100 ng/L) and goes deeply into the basis of solid-phase extractions that use surfactant-coated mineral oxide as sorbents.     

In situ derivatization/solid-phase microextraction: determination of polar aromatic amines

A solid-phase microextraction GC/MS method for the trace determination of a wide variety of polar aromatic amines in aqueous samples was developed. Prior to extraction the analytes were derivatized directly in the aqueous solution by diazotation and subsequent iodination in a one-pot reaction. The derivatives were extracted by direct-SPME using a PDMS/DVB fiber and analyzed by GC/MS in the full-scan mode. By diazotation/iodination, the polarity of the analytes was significantly decreased and as a consequence extraction yields were dramatically improved. The derivatization proved to be suitable for strongly deactivated aromatic amines and even the very polar diamino compounds can efficiently be enriched after derivatization. We investigated 18 anilines comprising a wide range of functional groups, which could be determined simultaneously. The method was thoroughly validated, and the precision at a concentration of 0.5 microg/L was 3.8-11% relative standard deviation for nonnitrated analytes using aniline-d(5) as internal standard and 3.7-10% for nitroaromatic amines without internal standard. The in situ derivatization/SPME/GC/MS method was calibrated over the whole analytical procedure and was linear over 2 orders of magnitude. Using 10-mL samples, detection limits of 2-13 ng/L were achieved for 15 of the 18 analytes. For two aminodinitrotoluene isomers and a diaminonitrotoluene, detection limits ranged from 27 to 38 ng/L. By allowing quantification at the 0.1 microg/L level, analysis of all target compounds meets EU drinking water regulations. The method provides high sensitivity, robustness, and high sample throughput by automation. Finally, the method was applied to various real water samples and in wastewater from a former ammunition plant the contents of several aromatic amines were quantified.     

Anaerobic stabilisation of sludge produced during municipal wastewater treatment by electrocoagulation

Anaerobic digestion of sludge from small electrocoagulation wastewater treatment plant (SEWWTP) is described. The sludge for digestion (SEWWTP sludge) was taken from pilot-scale SEWWTP with the capacity of about 200-population equivalent (25 m3 of municipal wastewater per day). Due to the technology of wastewater treatment, the characteristics of SEWWTP sludge was different from sludge produced in conventional mechanical-biological wastewater treatment plant. Therefore, experiments were focused on possibilities of anaerobic sludge digestion and determination of conditions and parameters (amount and quality of the sludge, biogas production, etc.). Average COD removal efficiency in the pilot-scale SEWWTP exceeded 80%. Organic content of excess sludge (volatile suspended solids (VSS)) was in the range of 52.1-59.2% (these values are much lower compared to VSS content in raw sludge from conventional municipal wastewater treatment plant, where VSS is about 75%). Biogas production from anaerobic digestion of SEWWTP sludge was approximately three times lower compared to standard production in conventional municipal wastewater treatment plant. Low pH (6.5-6.7), high concentration of iron (up to 1400 mg/L) and aluminium (up to 1300 mg/L) and very low (almost zero) concentration of dissolved phosphorus in sludge water were the main factors limiting the rate of anaerobic processes. Based on these results, anaerobic digestion of SEWWTP sludge was not recommended as an appropriate stabilisation method.     

Identification and measurement of illicit drugs and their metabolites in urban wastewater by liquid chromatography-tandem mass spectrometry

Residues of illicit drugs and their metabolites that are excreted by humans may flow into and through wastewater treatment plants. The aim of this study was to develop a method for the determination of cocaine, amphetamines, morphine, cannabinoids, methadone, and some of their metabolites in wastewater. Composite 24-h samples from urban treatment plants were enriched with deuterated internal standards before solid-phase extraction. High-pressure liquid chromatography tandem mass spectrometry with multiple reaction monitoring was used for quantitation. Recoveries were generally higher than 80%, and limits of quantifications were in the low nanograms-per-liter range for untreated and treated wastewater. The overall variability of the method was lower than 10% for untreated and 5% for treated wastewater. The method was applied to wastewater samples coming from two treatment plants in Italy and Switzerland. Quantification ranges were found to be 0.2-1 microg/L for cocaine and its metabolite benzoylecgonine, 80-200 ng/L for morphine, 10 ng/L for 6-acetylmorphine, 60-90 ng/L for 11-nor-9-carboxy-Delta9-tetrahydrocannabinol, 10-90 ng/L for methadone and its main metabolite 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine, and lower than 20 ng/L for amphetamines. As previously reported for cocaine, this method could be useful to estimate and monitor drug consumption in the population in real time, helping social scientists and authorities to combat drug abuse.