Simultaneous determination of selected endocrine disrupters (pesticides,phenols and phthalates) in water by in-field solid-phase extraction (SPE) using the prototype PROFEXS followed by on-line SPE (PROSPEKT) and analysis by liquid chromatography-atmospheric pressure chemical ionisation-mass spectrometry

In this study, a new procedure, based on on-line solid-phase extraction (SPE) and analysis by liquid-chromatography-atmospheric pressure chemical ionization-mass spectrometry (LC-APCI-MS), has been developed for the simultaneous, multianalyte determination of 21 selected pesticides, phenols and phthalates in water. SPE was carried out on polymeric PLRP-s cartridges by percolating 20 mL-samples. For sample preconcentration, the performance of a prototype programmable field extraction system (PROFEXS) was evaluated against the commercial laboratory bench Prospekt system used for method development. The Profexs is designed for the automated on-site sampling, SPE preconcentration, and storage of up to 16 samples in SPE cartridges. These cartridges are further eluted and on-line analyzed with the Prospekt coupled to the chromatographic system. In the optimized method, where completely on-line SPE-LC-MS analysis of the samples is carried out with the Prospekt in the laboratory, detection limits lower than 100 ng/L, and satisfactory precision (relative standard deviations <25%) and accuracies (recovery percentages >75%) were obtained for most investigated compounds from the analysis of spiked Milli-Q water. The extraction efficiency achieved with the Profexs was comparable to that of the Prospekt for most compounds and somewhat lower for the most apolar analytes, probably due to adsorption on the pump filters. The completely on-line optimized method was applied to the analysis of surface water, ground water and drinking water from a waterworks in Barcelona. Some pesticides and phenols were found in both surface water and groundwater at ng/L or µg/L levels, but not in the final drinking water. Di(2-ethylhexyl)phthalate (DEHP) was present in all samples investigated, including blanks. To the author's knowledge, this is the first work describing the application of a fully automated on-line SPE-LC-MS method for the simultaneous analysis of pesticides, phenols, and phthalates in water, and the second one that examines the possibilities of the prototype Profexs for automated on-site SPE preconcentration of organic pollutants from water samples.     

Determination of microcystins in blue-green algae, fish and water using liquid chromatography with ultraviolet detection after sample clean-up employing immunoaffinity chromatography

Anti-microcystin LR immunnoaffinity cartridges were evaluated for their ability to selectively remove microcystins from extracts of blue-green algae, fish and water samples for subsequent analysis by liquid chromatography with UV absorbance detection at 238 nm. Blue-green algae and fish samples were extracted with 75% methanol in water. A portion of the extract was diluted and passed through an immunoaffinity cartridge. Water samples were applied directly to the cartridge. The cartridge was rinsed with water and 25% methanol in water. The microcystins were eluted with 80% methanol in water containing 4% acetic acid. It was found that the cartridges were effective in isolating the microcystins from blue-green algae, fish and water samples, resulting in extracts that were clean enough to enable direct LC-UV detection down to approximately 0.03 microg/g in the blue-green algae and fish samples, and as low as 0.02 ng/ml for water samples. The cartridges were found to have a capacity of approximately 200 ng each for a mixture of microcystins RR, YR, LR and LA, or as much as 525-800 ng for individual compounds. Recoveries trough the complete analytical procedure ranged from 64 to 115% (all values) with an overall average of approximately 80% at spiking levels of 0.5-4.0 microg/g for the microcystins in blue-green algae. The average recoveries (n=8) from spiked (0.1-0.5 microg/g) fish samples were 73% for RR, 79% for YR, 81% for LR and 77% for LA, while from the spiked (2.0-0.04 ng/g) tap and river water samples (n=6), recoveries were 78% for RR, 86% for YR, 94% for LR and 89% for LA.     

Analysis of perfluorooctanesulfonate and related fluorochemicals in water and biological tissue samples by liquid chromatography-ion trap mass spectrometry

A method for the determination of perfluorinated compounds (PFCs) in various water and biological tissue samples was developed and validated. The contents of selected PFCs (i.e., perfluorooctanesulfonate (PFOS), perfluorooctanoate (PFOA) and perfluorodecanoate (PFDA)) in water samples were extracted by the C(18) solid-phase extraction (SPE). The biological tissue samples (frozen-dried fish and oysters) were simply extracted by liquid-solid extraction with MTBE and adding tetrabutylammonium hydrogensulfate (TBA) as an ion-pairing reagent. The analytes were then identified and quantitated by liquid chromatography-ion trap negative electrospray mass spectrometry (LC-ESI ion-trap-MS). Limits of quantitation (LOQ) were established between 0.5 and 6 ng/l in 250 ml of water sample, while 5-50 ng/g (dry weight) for biological tissue sample. Intrabatch and interbatch precision with their accuracy at two concentration levels were also investigated. Precision for these three PFCs, as indicated by RSD, proved to be less than 11 and 17%, respectively. The total contents of PFOA, PFOS and PFDA were detected in concentrations of up to 400 ng/l in various water samples, while up to 1,100 ng/g in fish and oyster samples. PFOA and PFDA was the major PFCs detected in water samples and biological tissue samples, respectively.     

Trace Determination of Rhodamine B and Rhodamine 6G Dyes in Aqueous Samples by Solid‐phase Extraction and High‐performance Liquid Chromatography Coupled with Fluorescence Detection

A simple and reliable method was developed to detect two basic synthetic dyes, rhodamine B (RB) and rhodamine 6G (R6G), in wastewater and surface water samples by high performance liquid chromatography with fluorescence detection (HPLC‐FLD). These dyes have been reported to be both mutagenic and carcinogenic in various organisms. The contents of these two dyes in water samples were extracted by Oasis HLB solid‐phase extraction (HLB‐SPE), and were then determined by an isocratic HPLC using an Atlantis® T3‐C18 column. Water samples at various pH conditions and the compositions of eluents for SPE were evaluated. The results indicate that the proposed method is precise and sensitive in analyzing these two basic synthetic dyes, and the limits of quantitation were 1.5 ng/L for RB and 0.3 ng/L for R6G in 100 mL of water samples. The recovery of analytes in spiked surface water and municipal wastewater treatment plant (WWTP) effluent samples ranged from 61 to 90% with the precision (RSD) ranging from 2 to 12%. The concentrations of analytes were detected in various water samples ranging from 0.7 to 81 ng/L.     

Automated trace level determination of glyphosate and aminomethyl phosphonic acid in water by on-line anion-exchange solid-phase extraction followed by cation-exchange liquid chromatography and post-column derivatization.

An automated method based on the on-line coupling of anion-exchange solid-phase extraction (SPE) and cation-exchange liquid chromatography followed by post-column derivatization and fluorescence detection has been developed for the trace level determination of glyphosate and its primary conversion product aminomethyl phosphonic acid (AMPA) in water. PRP-X100 poly(styrene-divinylbenzene)-trimethylammonium anion-exchange cartridges (20 x 2 mm, 10 microm) were selected for the SPE of glyphosate and AMPA. The ionic compounds present in the samples strongly influenced the extraction of both analytes; however, when an on-line ion-exchange clean-up step was introduced before sample SPE, the problem was largely solved. By processing 100-ml samples detection limits better than 0.02 microg/l for glyphosate and 0.1 microg/l for AMPA were achieved in river water. Both analytes were unstable in solution and the approach of storing samples on the PRP-X100 SPE cartridges was evaluated for a period of 1 month under three different storage conditions (deep freeze, refrigeration and 20 degrees C).     

Enhancing concentration and mass sensitivities for liquid chromatography trace analysis of clopyralid in drinking water

A theoretical treatment was developed and validated that relates analyte concentration and mass sensitivities to injection volume, retention factor, particle diameter, column length, column inner diameter and detection wavelength in liquid chromatography, and sample volume and extracted volume in solid‐phase extraction (SPE). The principles were applied to improve sensitivity for trace analysis of clopyralid in drinking water. It was demonstrated that a concentration limit of detection of 0.02 ppb (μg/L) for clopyralid could be achieved with the use of simple UV detection and 100 mL of a spiked drinking water sample. This enabled reliable quantitation of clopyralid at the targeted 0.1 ppb level. Using a buffered solution as the elution solvent (potassium acetate buffer, pH 4.5, containing 10% of methanol) in the SPE procedures was found superior to using 100% methanol, as it provided better extraction recovery (70–90%) and precision (5% for a concentration at 0.1 ppb level). In addition, the eluted sample was in a weaker solvent than the mobile phase, permitting the direct injection of the extracted sample, which enabled a faster cycle time of the overall analysis. Excluding the preparation of calibration standards, the analysis of a single sample, including acidification, extraction, elution and LC run, could be completed in 1 h. The method was used successfully for the determination of clopyralid in over 200 clopyralid monoethanolamine‐fortified drinking water samples, which were treated with various water treatment resins.     

Analysis of 29 per- and polyfluorinated compounds in water,sediment, soil and sludge by liquid chromatography–tandem mass spectrometry

Several analytical methods were optimised for the analysis of 29 per- and polyfluoroalkyl substances (PFASs), including perfluorocarboxylic acids, perfluoroalkyl sulphonic acids and fluorotelomers (FTs), such as sulphonate, saturated carboxylic acid, unsaturated carboxylic acid, sulphonamide and sulphonamide betaine (FTAB), in environmental samples in order to assess pollution by PFASs around heavily contaminated sites. Non-filtered water samples were extracted, purified and pre-concentrated by a solid-phase extraction (SPE) procedure. Solid samples (sediments, soils and sludges) were extracted through solvent extraction under acidic conditions and thereafter purified and pre-concentrated using the same SPE procedure as for the water samples. An ultra-high performance liquid chromatography coupled to tandem mass spectrometry in negative electrospray ionisation mode was employed to separate and detect targeted compounds. Twelve labelled internal standards were used to provide an adequate correction compensating for matrix effects. The limits of quantification (LOQs) were between 4 and 10 ng/L in water depending on the analytes. For solid samples, the LOQs were 2 ng/g dry weight (dw) in sediments and soils, and 20 ng/g dw in sludges for all analytes. A surrogate parameter method based on the carboxylation of perfluoroalkyl acid precursors under basic pH conditions was furthermore implemented to estimate the occurrence of non-targeted PFAS compounds. In order to evaluate the reliability of these analytical methods, environmental samples collected around a training area in France, where aqueous fire-fighting foam is used, were analysed. Of all the compounds detected in these environmental samples, 6:2 FTAB was found in the highest concentrations.     

A Microwave‐assisted Headspace Solid‐phase Microextraction for Rapid Determination of Synthetic Polycyclic and Nitro‐aromatic Musks in Fish Samples

Rapid solvent‐free microwave‐assisted headspace solid‐phase microextraction (MA‐HS‐SPME) coupled with gas chromatography‐mass spectrometry (GC‐MS) was developed to determine synthetic polycyclic and nitro‐aromatic musks in fish samples. Four commonly used synthetic musks, galaxolide (HHCB), tonalide (AHTN), musk xylene (MX) and musk ketone (MK) were employed in the method development and validation. The parameters (microwave irradiation time, irradiation power, amount of water addition, pH value and addition of NaCl) affecting the extraction efficiency of analytes from fish slurry were systematically investigated and optimized. The best extraction conditions were achieved when the fish sample 2‐g mixed with 4‐mL methanol and 15‐mL deionized water (containing 4 g of NaCl, pH 2.0 in a 40‐mL sample‐vial) was microwave irradiated at 80 watt for 5 min. The limits of quantification (LOQ) were 0.4 to 1.2 ng/g in 2‐g of wet tissue. The precision for these analytes, as indicated by relative standard deviations, were less than 9% for both intra‐ and inter‐day analysis. Accuracy, expressed as the mean extraction recovery, was between 80 to 92%. A standard addition method was used to quantitate these four synthetic musks, and the total concentrations ranged from 2.1 to 23.1 ng/g in various fish samples.     

Enrichment and low‐level determination of glyphosate,aminomethylphosphonic acid and glufosinate in drinking water after cleanup by cation exchange resin

For the determination of glyphosate, aminomethylphosphonic acid and glufosinate in drinking water, different procedures of enrichment and cleanup were examined using anion exchange or SPE. In many cases interactions of, e.g. alkaline earth metal ions especially calcium could be observed during enrichment and cleanup resulting in loss of analytes. For that reason, a novel cleanup and enrichment procedure for the determination of these phosphonic acid herbicides has been developed in drinking water using cation‐exchange resin. In summary, the cleanup procedure with cation‐exchange resin developed in this study avoids interactions as described above and is applicable to calcium‐rich drinking water samples. After derivatization with 9‐fluorenylmethylchloroformate followed by LC with fluorescence detection, LOD of 12, 14 and 12 ng/L and mean recoveries from real‐world drinking water samples of 98±9, 100±16 and 101±11% were obtained for glyphosate, aminomethylphosphonic acid and glufosinate, respectively. The low LODs and the high precision permit the analysis of these phosphonic acid herbicides according to the guidelines of the European Commission.     

高效液相色谱法同时测定食品中6种对羟基苯甲酸酯

建立了同时检测食品中6种对羟基苯甲酸酯的高效液相色谱-二极管阵列检测器( HPLC-DAD)定量分析方法.样品用乙腈提取,经LC-C18固相萃取柱净化,采用Agilent C18色谱柱分离,甲醇/水溶液梯度洗脱,二极管阵列检测器检测,外标法定量.结果表明:6种对羟基苯甲酸酯在1.0～500.0 mg/L范围内线性关系良好(r≥0.9997);检出限为0.0016～0.0081 mg/L(S/N=3);6种对羟基苯甲酸酯各添加水平在经表面处理的新鲜蔬菜、水果、醋、碳酸饮料及牛奶,食品馅料中的回收率为85.1％～95.4％;相对标准偏差为3.6％～10.9％.     

On-line solid phase extraction LC-MS/MS analysis of pharmaceutical indicators in water: A green alternative to conventional methods

A method using automated on-line solid phase extraction (SPE) directly coupled to liquid chromatography/tandem mass spectrometry (LC-MS/MS) has been developed for the analysis of six pharmaceuticals by isotope dilution. These selected pharmaceuticals were chosen as representative indicator compounds and were used to evaluate the performance of the on-line SPE method in four distinct water matrices. Method reporting limits (MRLs) ranged from 10 to 25 ng/L, based on a 1 mL extraction volume. Matrix spike recoveries ranged from 88 to 118% for all matrices investigated, including finished drinking water, surface water, wastewater effluent and septic tank influent. Precision tests were performed at 50 and 1000 ng/L with relative standard deviations (RSDs) between 1.3 and 5.7%. A variety of samples were also extracted using a traditional off-line automated SPE method for comparison. Results for both extraction methods were in good agreement; however, on-line SPE used approximately 98% less solvent and less time. On-line SPE coupled to LC-MS/MS analysis for selected indicators offers an alternative, more environmentally friendly, method for pharmaceutical analysis in water by saving time and costs while reducing hazardous waste and potential environmental pollution as compared with off-line SPE methods.     

Pipette tip solid-phase extraction and gas chromatography – mass spectrometry for the determination of methamphetamine and amphetamine in human whole blood

Methamphetamine and amphetamine were extracted from human whole blood samples using pipette tip solid-phase extraction (SPE) with MonoTip C₁₈ tips, on which C₁₈-bonded monolithic silica gel was fixed. Human whole blood (0.1 mL) containing methamphetamine and amphetamine, with N-methylbenzylamine as an internal standard, was mixed with 0.4 mL of distilled water and 50 μL of 5 M sodium hydroxide solution. After centrifugation, the supernatant was extracted to the C₁₈ phase of the tip (pipette tip volume, 200 μL) by 25 repeated aspirating/dispensing cycles using a manual micropipettor. Analytes retained in the C₁₈ phase were eluted with methanol by five repeated aspirating/dispensing cycles. After derivatization with trifluoroacetic anhydride, analytes were measured by gas chromatography – mass spectrometry with selected ion monitoring in the positive-ion electron impact mode. Recoveries of methamphetamine and amphetamine spiked into whole blood were more than 87.6 and 81.7%, respectively. Regression equations for methamphetamine and amphetamine showed excellent linearity in the range of 0.5–100 ng/0.1 mL. The limits of detection for methamphetamine and amphetamine were 0.15 and 0.11 ng/0.1 mL, respectively. Intra- and interday coefficients of variation for both stimulants were not greater than 9.6 and 13.8%, respectively. The determination of methamphetamine and amphetamine in autopsy whole blood samples is presented, and was shown to validate the present methodology.     

Gas chromatography with atomic emission detection for dimethylselenide and dimethyldiselenide determination in waters and plant materials using a purge-and-trap preconcentration system

Dimethylselenide (DMSe) and dimethyldiselenide (DMDSe) were determined in plant and water samples by capillary gas chromatography using microwave induced-plasma atomic emission spectrometry for detection. The analytes were leached from the solid samples into methanol by using an ultrasonic probe, and a portion of the extract was preconcentrated by means of a purge-and-trap system before being chromatographed. The analytes were directly purged from the water samples in the presence of 6% (v/v) methanol. Element-specific detection and quantification was carried out by monitoring the selenium (196 nm) emission line. Calibration curves were obtained by plotting peak area versus concentration and the correlation coefficients for linear calibration were 0.9999 for both analytes. Detection limits of 0.8 and 1.1 ng l(-1) were obtained for DMSe and DMDSe, respectively, for water samples. For plant materials, the detection limits calculated for 0.5 g samples were 0.3 and 0.4 ng g(-1) for DMSe and DMDSe, respectively. Concentration levels of DMSe ranging from 1.2 to 4.2 ng g(-1) were found in some of the plant materials analyzed. No DMDSe was found in any of the samples. The accuracy of the method was checked by analyzing different spiked water and plant samples.     

高效液相色谱-串联质谱法测定果蔬中7种植物生长促进剂残留

建立了果蔬样品中对氯苯氧乙酸、赤霉酸(GA3)、2,4-二氯苯氧乙酸、α-萘乙酸、吲哚丁酸、6-苄氨基嘌呤、氯吡脲残留的高效液相色谱-串联质谱(HPLC-MS/MS)分析方法。样品用甲醇匀质提取2次,经Waters C18固相萃取小柱净化后,在高效液相色谱-串联质谱仪(HPLC-MS/MS)选择反应监测(SRM)模式下测定。采用质谱定性,外标法定量。色谱柱为Hypersil GOLD aQ(150 mm×2.1 mm,3μm)柱,以甲醇和水为流动相,梯度洗脱。果蔬样品在低、中、高3个加标水平下的平均回收率为79%～97%,相对标准偏差均不高于7.6%。7种植物生长促进剂在果蔬样品中的方法检出限为0.40～20.0μg/kg。该方法灵敏度高、操作简单,可作为大批量果蔬中植物生长促进剂残留的检测方法。     

Fast analysis of quaternary ammonium pesticides in food and beverages using cation‐exchange chromatography coupled with isotope‐dilution high‐resolution mass spectrometry

A fast separation based on cation‐exchange liquid chromatography coupled with high‐resolution mass spectrometry is proposed for simultaneous determination of chlormequat, difenzoquat, diquat, mepiquat and paraquat in several food and beverage commodities. Solid samples were extracted using a mixture of water/methanol/formic acid (69.6:30:0.4, v/v/v), while liquid samples were ten times diluted with the same solution. Separation was carried out on an experimental length‐modified IonPac CS17 column (2 × 15 mm²) that allowed the use of formic acid and acetonitrile as mobile phase. Detection limits for food and beverage matrices were established at 1.5 μg/L for chlormequat, difenzoquat and mepiquat, and 3 μg/L for diquat and paraquat, while for drinking water a pre‐analytical sample concentration allowed detection limits of 9 and 20 ng/L, respectively. Precision, as repeatability (RSD%), ranged from 0.2 to 24%, with a median value of 6%, and trueness, as recovery, ranged from 64 to 118%, with a median value of 96%. The method developed was successfully applied to investigate the presence of herbicide residues in commercial commodities (mineral water, orange juice, beer, tea, green coffee bean, toasted coffee powder, cocoa bean, white corn flour, rice and sugar samples).     

On‐line flow‐through extraction–preconcentration‐large volume injection‐RP LC for trace determination of pyrethroids in Slovak soil

A rapid micro‐analytical multiresidue method was developed for analysis of pyrethroids (kadethrin K, cypermethrin C and permethrin P) in soil micro‐sample (200 mg). It uses on‐line flow‐through extraction of soil micro‐samples (packed into a short glass column) with a methanol‐aqueous citric acid buffer mixture, successive on‐line SPE preconcentration of analytes from the extract and on‐line RP‐HPLC analysis with UV photometric detection. The separation of pyrethroids is performed on a Purospher RP‐18e column with methanol/water as mobile phase. Effects of sorbent placed at the bottom of a short column holding the soil sample and different kinds of on‐line SPE columns were tested. Besides, the influence of volume of the effluent on the pyrethroids recovery was also studied. Calibration curves were linear over the range assayed from 0.01 to 0.2 μg/mL with correlation coefficients of linear regression (least‐squares method) in the range 0.998–0.999. Recovery studies were carried out at 0.25–1.00 μg/g dry soil fortification level and obtained recoveries were for K 81–84%, C 56–59% and for P 58–63%. Achieved LOD (confidence band) of studied pyrethroids were for large‐volume injection (1 mL) 4.5 ng K, 3.7 ng C, 3.6 ng P or 27 ng/g K, 32 ng/g C and 29 ng/g P in dry soil “solid sampling HPLC”.     

Determination of phenoxyacid herbicides and their phenolic metabolites in surface and drinking water.

An evaluation was made of the feasibility of using reversed-phase liquid chromatography/tandem mass spectrometry with an electrospray interface (LC/ESI-MS/MS) to measure traces of phenoxyacid herbicides and their metabolites in surface and drinking water samples. The procedure involved passing 0.5 L of river and drinking water samples through a 0.5 g graphitized carbon black (GCB) extraction cartridge. Recovery was higher than 85% irrespective of the aqueous matrix in which the analytes were dissolved. A conventional 4.6-mm i.d. reversed-phase LC C-18 column operating with a mobile phase flow rate of 1 mL/min was used to chromatograph the analytes. A flow of 200 microL/min of the column effluent was diverted to the ESI source. The limits of detection (signal-to-noise ratio = 3) of the method for the pesticides considered in drinking and surface water samples are less than 0.1 ng/L for phenoxyacid herbicides, and about 5-10 ng/L for their metabolites (2,4-dichlorophenol and 4-chloro-2-methylphenol).     

在线固相萃取/液相色谱-线性离子阱质谱法同时检测生物样品中18种氨基甲酸酯类农药

建立了同时测定全血、尿液和肝组织等生物样品中18种氨基甲酸酯类农药的在线固相萃取/液相色谱-线性离子阱质谱(On-line SPE/LC-LIT/MS)分析方法。样品经乙腈处理,稀释和离心后直接进样。经Waters OasisHLB在线SPE柱富集纯化,以BETASIL C18柱为分析柱,甲醇-水(均含0.1%甲酸)为流动相进行梯度洗脱;使用电喷雾电离(ESI)正离子模式测定,扫描方式为选择反应监测(SRM)和连续反应监测(CRM)。18种农药在考察的质量浓度范围内线性关系良好(权重因子1/X),相关系数为0.994 3~0.999 4;在全血和尿液中的检出限为0.1~5 ng/m L,在肝组织中的检出限为0.1~5 ng/g;3个加标水平的回收率为90.2%~114.5%,相对标准偏差(n=4)为0.5%~7.5%。该方法简单准确,灵敏度高,能够满足生物样品中18种氨基甲酸酯类农药的快速分析要求。     

Analysis of nitrosamines in water by automated SPE and isotope dilution GC/HRMS Occurrence in the different steps of a drinking water treatment plant, and in chlorinated samples from a reservoir and a sewage treatment plant effluent

A method based on automated solid-phase extraction (SPE) and isotope dilution gas chromatography/high resolution mass spectrometry (GC/HRMS) has been developed for the analysis of nine nitrosamines in water samples. The combination of automated SPE and GC/HRMS for the analysis of nitrosamines has not been reported previously. The method shows as advantages the selectivity and sensitivity of GC/HRMS analysis and the high efficiency of automated SPE with coconut charcoal EPA 521 cartridges. Low method detection limits (MDLs) were achieved, along with a greater facility of the procedure and less dependance on the operator with regard to the methods based on manual SPE. Quality requirements for isotope dilution-based methods were accomplished for most analysed nitrosamines, regarding to trueness (80–120%), method precision (<15%) and MDLs (0.08–1.7 ng/L).Nineteen water samples (16 samples from a drinking water treatment plant {DWTP}, 2 chlorinated samples from a sewage treatment plant {STP} effluent, and 1 chlorinated sample from a reservoir) were analysed. Concentrations of nitrosamines in the STP effluent were 309.4 and 730.2 ng/L, being higher when higher doses of chlorine were applied. N-Nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA) were the main compounds identified in the STP effluent, and NDEA was detected above 200 ng/L, regulatory level for NDMA in effluents stated in Ontario (Canada). Lower concentrations of nitrosamines were found in the reservoir (20.3 ng/L) and in the DWTP samples (n.d. −28.6 ng/L). NDMA and NDEA were respectively found in the reservoir and in treated and highly chlorinated DWTP samples at concentrations above 10 ng/L (guide value established in different countries). The highest concentrations of nitrosamines were found after chlorination and ozonation processes (ozonated, treated and highly chlorinated water) in DWTP samples.     

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A gas chromatography/ion trap mass spectrometry method was used for the trace analysis of atrazine and its deethylated degradation product deethylatrazine in environmental water and sediment samples. The isotope dilution technique was applied for the quantitative analysis of atrazine at parts-per-trillion levels. Water samples were pre-concentrated by solid-phase extraction using a C18 cartridge while the sediment samples were extracted by sonication with methanol. The concentrated extracts were analysed by a GC/ion trap MS operated in the MS/MS method. The extraction recoveries for the analytes were better than 83% when 1 L of water or 10 g of sediment was analysed. The method detection limits were 0.75 ng/L and 0.13 ng/g for atrazine and deethylatrazine detected in water and sediment, respectively. The precisions of the method represented by the relative standard deviation were in the range of 3.2-16.1%. The method was successfully applied to analyse surface water and sediment samples collected from Beijing Guanting reservoir. Trace levels of atrazine at 35.9-217.3 ng/L and 2.4-8.4 ng/g were detected in the water and sediment samples, respectively. The levels of deethylatrazine were five to 20 times lower that those of atrazine.