Investigating the presence of pesticide transformation products in water by using liquid chromatography-mass spectrometry with different mass analyzers

Many pesticide transformation products (TPs) can reach environmental waters as a consequence of their normally having a higher polarity than their parent pesticides. This makes the development of analytical methodology for reliable identification and subsequent quantification at the sub-microgram per liter levels necessary, as required under current legislation. In this paper we report the photodegradation of several pesticides frequently detected in environmental waters from the Spanish Mediterranean region using the high-resolution and exact-mass capabilities of hybrid quadrupole time-of-flight mass spectrometry (QTOF MS) hyphenated to liquid chromatography (LC). Once the main photodegradation/hydrolysis products formed in aqueous media were identified, analytical methodology for their simultaneous quantification and reliable identification in real water samples was developed using on-line solid-phase extraction (SPE)-LC-tandem MS with a triple-quadrupole (QqQ) analyzer. The methodology was validated in both ground and surface water samples spiked at the limit of quantification (LOQ) and 10 x LOQ levels, i.e. 50 and 500 ng/l, obtaining satisfactory recoveries and precision for all compounds. Subsequent analysis of ground and surface water samples resulted in the detection of a number of TPs higher than parent pesticides. Additionally, several soil-interstitial water samples collected from the unsaturated zone were analyzed to explore the degradation/transformation of some pesticides in the field using experimental plots equipped with lisimeters. Several TPs were found in these samples, with most of them having also been detected in ground and surface water from the same area. This paper illustrates the extraordinary potential of LC-MS(/MS) with QTOF and QqQ analyzers for qualitative/structural and quantitative analysis, respectively, offering analytical chemists one of the most powerful tools available at present to investigate the presence of pesticide TPs in water.     

Efficient approach for the reliable quantification and confirmation of antibiotics in water using on-line solid-phase extraction liquid chromatography/tandem mass spectrometry

The potential of solid-phase extraction coupled on-line to liquid chromatography/electrospray tandem mass spectrometry (SPE-LC-ESI-MS/MS) has been investigated in this paper for the efficient sensitive quantification and confirmation of 16 antibiotics in water. The list of targeted analytes included 10 quinolones (oxolinic acid (OXO), nalidixic acid (NAL), flumequine (FLU), marbofloxacine (MAR), ofloxacine (OFLO), enrofloxacine (ENR), pefloxacine (PEF), ciprofloxacine (CIP), pipemidic acid (PIPE), norfloxacine (NOR)) and 6 penicillins (penicillin G (PEN), oxacillin (OXA), dicloxacillin (DIC), piperacillin (PIP), cloxacillin (CLO) and ampicillin (AMP)) that were determined in ground and surface water. The procedure is based on the injection of 9.8 mL of sample into the SPE-LC-MS/MS system and the measurement of antibiotics by selected reaction monitoring mode, using a triple quadrupole analyser. The method has been validated at realistic low concentrations that might be present in environmental water, i.e. 10 and 100 ng L(-1), obtaining recoveries between 74% and 123% with relative standard deviation lower than 14%. Matrix effects were not relevant in most of cases, except for ampicillin in surface water, where notable signal suppression was observed. The limits of detection were as low as 0.4-4.3 ng L(-1). The method developed allows the rapid screening and quantification of all the analytes selected by acquiring one MS/MS transition (normally the most sensitive) for each compound. It was applied to a number of actual surface and groundwater samples with several compounds being detected, mainly quinolones, at low ng L(-1) levels. Special attention was given to the confirmation of compounds detected in water due to the difficulties of obtaining confident confirmation at low ng L(-1). This matter has been of growing concern in the last few years as reflected by recent papers and correspondence. The acquisition of several MS/MS transitions for each compound detected in a second independent analysis allowed the unequivocal confirmation of identity, avoiding reporting false-positives. Finally, the potential of QTOF instruments to confirm positive samples has also been evaluated and compared with triple quadrupole analysers.     

Simultaneous ultra-high-pressure liquid chromatography–tandem mass spectrometry determination of amphetamine and amphetamine-like stimulants,cocaine and its metabolites,and a cannabis metabolite in surface water and urban wastewater

An ultra-high-pressure liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) method has been developed for the simultaneous quantification and confirmation of 11 basic/acidic illicit drugs and relevant metabolites in surface and urban wastewater at ng/L levels. The sample pre-treatment consisted of a solid-phase extraction using Oasis MCX cartridges. Analyte deuterated compounds were used as surrogate internal standards (except for norbenzoylecgonine and norcocaine) to compensate for possible errors resulting from matrix effects and those associated to the sample preparation procedure. After SPE enrichment, the selected drugs were separated within 6 min under UHPLC optimized conditions. To efficiently combine UHPLC with MS/MS, a fast-acquisition triple quadrupole mass analyzer (TQD from Waters) in positive-ion mode (ESI+) was used. The excellent selectivity and sensitivity of the TQD analyzer in selected reaction monitoring mode allowed quantification and reliable identification at the LOQ levels. Satisfactory recoveries (70–120%) and precision (RSD < 20%) were obtained for most compounds in different types of water samples, spiked at two concentration levels [limit of quantification (LOQ) and 10LOQ]. Thus, surface water was spiked at 30 ng/L and 300 ng/L (amphetamine and amphetamine-like stimulants), 10 ng/L and 100 ng/L (cocaine and its metabolites), 300 ng/L and 3000 ng/L (tetrahydrocannabinol-COOH). Recovery experiments in effluent and influent wastewater were performed at spiking levels of three and fifteen times higher than the levels spiked in surface water, respectively. The validated method was applied to urban wastewater samples (influent and effluent). The acquisition of three selected reaction monitoring transitions per analyte allowed positive findings to be confirmed by accomplishment of ion ratios between the quantification transition and two additional specific confirmation transitions. In general, drug consumption increased in the weekends and during an important musical event. The highest concentration levels were 27.5 μg/L and 10.5 μg/L, which corresponded to 3,4-methylenedioxymethamphetamine (MDMA, or ecstasy) and to benzoylecgonine (a cocaine metabolite), respectively. The wastewater treatment plants showed good removal efficiency (>99%) for low levels of illicit drugs in water, but some difficulties were observed when high drug levels were present in wastewaters.     

Determination of priority organic micro-pollutants in water by gas chromatography coupled to triple quadrupole mass spectrometry

A multiclass method has been developed for screening, quantification and confirmation of organic micro-pollutants in water by gas chromatography coupled to mass spectrometry with a triple quadrupole analyzer. The work has been focused on the determination of more than 50 compounds belonging to different chemical families: 19 organochlorine and organophosphorus insecticides, 6 herbicides, 7 polychlorinated biphenyls, 16 polycyclic aromatics hydrocarbons, 2 brominated diphenyl ethers, and 3 octyl/nonyl phenols and pentachlorobenzene. Most of these analytes are included in the list of priority substances in the framework on European Water Policy.Analyte extraction was performed by solid phase extraction using C₁₈ cartridges, and five isotopically labeled standards were added before extraction as surrogates. Analyses were performed by gas chromatography with tandem mass spectrometry (MS/MS) in electron impact mode. Accuracy and precision were evaluated by means of recovery experiments using water samples fortified at two concentration levels (25 and 250 ng L⁻¹), with satisfactory results for most of analytes. The excellent selectivity and sensitivity reached in selected reaction monitoring mode allowed us satisfactory quantification and confirmation at levels as low as 25 ng L⁻¹. Two MS/MS transitions were acquired for each analyte, using the Q/q intensity ratio as a confirmatory parameter. The method developed was applied to the analysis of surface, ground and wastewater samples collected from the Valencia Region (Spain).Analytical methodology using negative chemical ionization mode was also validated for the organochlorine compounds selected, showing a superior sensitivity and lower detection limits.     

Simultaneous determination of triazines and their main transformation products in surface and urban wastewater by ultra-high-pressure liquid chromatography–tandem mass spectrometry

This work describes the optimization, validation and application of an ultra-high-pressure liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS) method for the quantification and confirmation of 11 compounds (atrazine, simazine, terbuthylazine, terbumeton, terbutryn and their main transformation products) in surface and wastewater samples. Several of these analytes are included in the list of priority substances in the framework on European Water Policy. The application of this method to water samples reveals that the most relevant transformation products (TPs) should be incorporated into current analytical methods to obtain a more realistic knowledge of water quality regarding pesticide contamination. TPs are generally more polar and mobile than parents and can be transported to the aquatic environment more easily than their precursors. This can explain their concentrations found in water, which in many cases are much higher than intact triazines. To efficiently combine UHPLC with MS/MS, a fast-acquisition triple quadrupole mass analyser was used. Working in selected reaction monitoring mode, up to three simultaneous transitions per compound were acquired, allowing a reliable quantification and confirmation at nanogram per litre levels. The method developed includes a pre-concentration step based on solid-phase extraction (OASIS HLB cartridges). Satisfactory recoveries (70–120%) and relative standard deviations (<20%) were obtained for all compounds in different water sample types spiked at two concentrations (0.025 and 0.1 μg/L in surface water; 0.25 and 1.0 μg/L in effluent wastewater; 0.5 and 2.0 μg/L in influent wastewater). The optimized method was found to have excellent sensitivity with instrumental detection limits as low as 0.03 pg. In addition, the influence of the matrix constituents on the ionization efficiency and the extraction recovery was studied in different types of Italian and Spanish surface and urban wastewater. Signal suppressions were observed for all compounds, especially for influent wastewater. The use of isotope-labelled internal standards was found to be the best approach to assure an accurate quantification in all matrix samples.     

固相萃取/超高效液相色谱-串联质谱法快速测定不同水体中5种人造甜味剂、6种造影剂及咖啡因

建立了快速检测不同水样(地表水、污水处理厂进水和出水)中5种人造甜味剂、6种造影剂和咖啡因的超高效液相色谱-串联质谱(UPLC-MS/MS)方法。利用HR-X固相萃取柱对过滤后的水样进行富集净化。采用Zorbax SB-C_(18)色谱柱分离,电喷雾正模式(ESI+)和负模式(ESI-)下分别以乙腈-水(10 mmol/L乙酸铵,0.01%甲酸)和乙腈-水(5 mmol/L乙酸铵,1 mmol/L Tris)为流动相,多反应监测模式(MRM)检测。各目标化合物在5~5 000μg/L范围内线性关系良好,相关系数均大于0.998。地表水、污水处理厂进水和出水的回收率为70%~120%,相对标准偏差(RSD)为0.8%~19.0%,方法检出限(MDL)分别为0.43~13.8、1.80~34.8、2.30~134 ng/L。应用该方法对广州某污水处理厂进水和出水及受纳河流河水进行检测,除阿斯巴甜、碘他拉酸、碘普罗胺、碘美普尔外,其他物质均有检出且浓度较高。该方法准确、灵敏、操作简便,适用于多种环境水样中人造甜味剂、造影剂和咖啡因的分析检测。     

Simultaneous determination of acidic,neutral and basic pharmaceuticals in urban wastewater by ultra high-pressure liquid chromatography-tandem mass spectrometry

In this work, an ultra high-pressure liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method has been developed for the simultaneous quantification and confirmation of the 20 most consumed pharmaceuticals in Spain in urban wastewater and surface water samples. The scope of the method included acidic, neutral and basic compounds belonging to different therapeutic classes and allows their simultaneous determination in just a single injection, giving realistic information of the most widely consumed pharmaceuticals in only one analysis. An enrichment step based on solid-phase extraction using Oasis HLB cartridges was carried out, followed by UHPLC-MS/MS measurement with a fast-acquisition triple quadrupole mass analyzer. It allowed working with short dwell times and made possible to acquire three simultaneous SRM transitions per compound to assure a reliable identification. Several isotope-labelled internal standards were used as surrogates to correct SPE losses, as well as matrix effects that notably affect quantification of analytes. The method was validated in surface water and effluent and influent urban wastewater at different concentrations from 0.005 μg/L (surface water) to 1.25 μg/L (influent wastewater). The optimized method was applied to the analysis of 84 urban wastewater samples (influent and effluent), with the result that 17 out of 20 compounds monitored were detected in the samples. Analgesics and anti-inflamatories, cholesterol lowering statin drugs and lipid regulators were the major groups found, with diclofenac, ketoprofen, naproxen, 4-aminoantipyrine, bezafibrate, gemfibrozil and venlafaxine being the most frequently detected. The highest concentration level reached was 277 μg/L for salicylic acid in influent wastewater.     

Simultaneous determination of benzotriazoles and ultraviolet filters in ground water, effluent and biosolid samples using gas chromatography-tandem mass spectrometry

A new method using gas chromatography-tandem mass spectrometry (GC-MS/MS) was developed for the determination of four benzotriazoles, i.e. benzotriazole (BT), 5-methylbenzotriazole (5-TTri), 5-chlorobenzotriazole (CBT), 5,6-dimethylbenzotriazole (XTri), and six UV filters, i.e. benzophenone-3 (BP-3), 3-(4-methylbenzylidene)camphor (4-MBC), octyl 4-methoxycinnamate (OMC), 2-(3-t-butyl-2-hydroxy-5-methylphenyl)-5-chloro benzotriazole (UV-326), 2-(2'-hydroxy-5'-octylphenyl)-benzotriazole (UV-329), and octocrylene (OC) in ground water, effluent and biosolid samples. Solid phase extraction (SPE) and pressurized liquid extraction (PLE) were applied as the preconcentration method for water samples (ground water and effluent) and biosolid samples, respectively. The optimized method allowed us to quantify all target compounds with the method detection limits ranging from 0.29 to 11.02 ng/L, 0.5 to 14.1 ng/L and 0.33 to 8.23 ng/g in tap water, effluent and biosolid samples, respectively. The recoveries of the target analytes in tap water, effluent and biosolid samples were 70-150%, 82-127% and 81-133%, respectively. The developed analytical method was applied in the determination of these target compounds in ground water, effluent and biosolid samples collected from Bolivar sewage treatment plants in South Australia. In effluent samples, the target compounds BT, 5-TTri, CBT, XTri and BP-3 tested were detected with the maximum concentration up to 2.2 μg/L for BT. In biosolid samples, eight out of ten compounds tested were found to be present at the concentrations ranging between 18.7 ng/g (5-TTri) and 250 ng/g (4-MBC).     

Determination of estrogenic steroids in surface water and wastewater by liquid chromatography-electrospray tandem mass spectrometry

An analytical method is presented which permits trace level determination of 17alpha-ethynylestradiol (EE2), 17beta-estradiol (E2), and estrone (E1). Using this method, the estrogenic steroids were analyzed in drinking water, surface water, and wastewater (sewage influents and effluents) at concentrations down to 0.1 ng/L. Sample volumes between 100 and 500 mL are concentrated using automated solid-phase extraction. Analysis is performed by liquid chromatography with detection by tandem mass spectrometry. Applying simple clean-up procedures and internal standard calibration, recovery losses resulting from matrix-dependent ion suppression during electrospray ionization could be compensated for all of the investigated compounds. Recoveries around 100% were obtained for all analytes after correction using the internal standards. Limits of quantification (LOQ) were between 0.1 and 0.4 ng/L for purified sewage, surface, ground, and drinking water and between 1 and 2 ng/L in the case of raw sewage. Water treatment by wastewater treatment plants (WWTPs) or by a surface water treatment plant affected the removal of all estrogenic steroids. Thus, E1, E2, and EE2 were removed in the municipal WWTPs to the extent of 93%, 93%, and 80%, respectively. In the effluents of the WWTP in Ruhleben (Berlin, Germany), E1, E2, and EE2 were detected at the low ng/L level. E2 and EE2 were, however, not present in the Berlin surface water above the LOQ (0.2 ng/L). E1 was the only compound that could be detected in surface water samples. After additional surface water treatment it was still detectable but only at trace-level concentrations with a mean value of 0.16 ng/L.     

Multiresidue fully automated online SPE-HPLC-MS/MS method for the quantification of endocrine-disrupting and pharmaceutical compounds at trace level in surface water

The present work describes the development and validation of a sensitive method for the determination of traces of diverse groups of pharmaceuticals and endocrine disruptors in surface water. Thirty-seven substances have been selected, including 10 pesticides, 6 hormonal steroids and assimilates, 12 pharmaceuticals, 5 alkylphenols, 1 chlorophenol and 3 other well-known human contaminants, 1 UV filter and 2 plasticisers. An automated online solid-phase extraction (SPE) is directly coupled to liquid chromatography–tandem mass spectrometry. Different SPE columns have been tested, and the injection volume has been optimised. The developed analytical methodology is based on the direct injection of 2.5 mL of water sample acidified at pH 1.6 on an Oasis HLB loading column (20 × 2.1 mm) with 5-µm particles. Then, the chromatographic separation is achieved on a Kinetex XB C18 (100 × 2.1 mm; 1.7 µm) column, and the quantification is realised in multiple-reaction monitoring mode. The online SPE step warrants minimal sample handling, low solvent consumption, high sample throughput, saving time and costs. This method allows the quantification of the target analytes in the lower ng/L concentration range, with limits of quantification (LQs) between 100 pg/L and 10 ng/L, 26 compounds having LQ lower than 1 ng/L. The monitoring of two selected MS/MS transitions for each compound allows the reliable confirmation of positive findings even at the LQ level. The developed and validated methodology has been applied to the analysis of various real samples from two French rivers. Twelve target compounds have been detected in the environmental samples, and the major pollutants are pharmaceuticals usually used by humans (paracetamol, carbamazepine, oxazepam, ketoprofen, trimethoprim). The pesticides atrazine and carbendazim have been ubiquitously detected in real samples too. Metronidazole, sulfamethoxazole and diuron were also frequently quantified in the water samples.     

Trace determination of sulphur mustard and related compounds in water by headspace-trap gas chromatography–mass spectrometry

A method for trace determination of sulphur mustard (HD) and some of its cyclic decomposition compounds in water samples has been developed using headspace-trap in combination with gas chromatography–mass spectrometry (GC–MS). Factorial design was used for optimisation of the method. The trap technology allows enrichment and focusing of the analytes on an adsorbent, hence the technique offers better sensitivity compared to conventional static headspace. A detection limit of 1 ng/ml was achieved for HD, while the cyclic sulphur compounds 1,4-thioxane, 1,3-dithiolane and 1,4-dithiane could be detected at a level of 0.1 ng/ml. The method was validated for the stable cyclic compounds in the concentration range from the limit of quantification (LOQ: 0.2–0.4 ng/ml) to hundred times LOQ. The within and between assay precisions at hundred times LOQ were 1–2% and 7–8% relative standard deviation, respectively. This technique requires almost no sample handling, and the total time for sampling and analysis was less than 1 h. The method was successfully employed for muddy river water and sea water samples.     

Determination of isoflavones and coumestrol in river water and domestic wastewater sewage treatment plants

Phytoestrogens activate a biological response in vertebrata where they can mime or modulate the action of endogenous estrogens. For this reason they have been subjected to several studies about their physiological effects on humans and many analytical methodologies for their determination in food matrices and physiological fluids have been developed. On the contrary, little information can be found in literature about the presence of isoflavones and coumestrol in the environment, even if it is known that this may have significance. In the present study we investigated the presence of nine selected free and conjugated phytoestrogens in environmental water. A liquid chromatography-mass spectrometry (LC-MS/MS) based analytical methodology was developed and employed for detection of target compounds in surface water and wastewater.The methodology uses solid-phase extraction, followed by high performance liquid chromatography coupled to tandem mass spectrometry using an electrospray (ESI) interface operating in positive ion mode (LC-ESI-MS/MS). The extraction was made with 200 mg, 6 mL OASIS HLB^® cartridges. Recoveries for the selected compounds were in the 67-97% range for all the considered analytes. The method was employed for environmental monitoring. Samples of river water and wastewater collected over a 4-month period were analyzed with the developed procedure. Results showed the presence of isoflavones in most of the samples analyzed. Average concentration of target analytes found in wastewater sewage treatment plant influent ranged from 454 to 12 ng/L. In effluent water and river water the analytes were present at lower concentration.     

Hollow-fibre supported liquid membrane extraction for determination of fluoxetine and norfluoxetine concentration at ultra trace level in sewage samples

In this study, a method was developed for determining the concentration of the pharmaceutical fluoxetine and its metabolite, norfluoxetine, in sewage water samples. Sample preparation was performed by hollow-fibre supported liquid membrane (HF-SLM) extraction with final analysis using liquid chromatography with UV detection. Several parameters were studied including type of organic solvent, sample and acceptor pH, and salt and humic acid content. The optimised method allowed determination of the analyte at the ng/L level in sewage water. A linear plot gave a correlation coefficient better than 0.991 for both analytes and resulted in limits of detection in sewage water of 11 and 12 ng/L, for fluoxetine and norfluoxetine, respectively. The enrichment factor was over 1700 for both analytes in sewage water. The repeatability and reproducibility were better than 8% and 17%, respectively. The developed methodology was used to study daily variations of fluoxetine and norfluoxetine in municipal sewage streams. Norfluoxetine has been detected for the first time in sewage water and a preliminary analysis gave average concentrations of 150 and 225 ng/L for norfluoxetine and fluoxetine, respectively.     

Determination of two oxy-pyrimidine metabolites of diazinon in urine by gas chromatography/mass selective detection and liquid chromatography/electrospray ionization/mass spectrometry/mass spectrometry

An analytical method was developed for the determination in urine of 2 metabolites of diazinon: 6-methyl-2-(1-methylethyl)-4(1H)-pyrimidinone (G-27550) and 2-(1-hydroxy-1-methylethyl)-6-methyl-4(1H)-pyrimidinone (GS-31144). Two of the urine sample preparation procedures presented rely on gas chromatography/mass selective detection (GC/MSD) in the selected ion monitoring mode for determination of G-27550. For fast sample preparation and a limit of quantitation (LOQ) of 1.0 ppb, urine samples were purified by using ENV+ solid-phase extraction (SPE) columns. For analyte confirmation at an LOQ of 0.50 ppb, classical liquid/liquid partitioning was used before further purification in a silica SPE column. An SPE sample preparation procedure and liquid chromatography/electrospray ionization/mass spectrometry/mass spectrometry (LC/ESI/MS/MS) were used for both G-27550 and GS-31144. The limit of detection was 0.01 ng for G-27550 with GC/MSD, and 0.016 ng when LC/ESI/MS/MS was used for both G-27550 and GS-31144. The LOQ was 0.50 ppb for G-27550 when GC/MSD and the partitioning/SPE sample preparation procedure were used, and 1.0 ppb for the SPE only sample preparation procedure. The LOQ was 1.0 ppb for both analytes when LC/ESI/MS/MS was used.     

Hydrophilic interaction liquid chromatography/tandem mass spectrometry for the analysis of diallyldimethylammonium chloride in water

We report a selective, sensitive and fast liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for the determination of diallyldimethylammonium chloride (DADMAC) in water. Hydrophilic interaction liquid chromatography (HILIC) was used to avoid ion-pairing reagents, which are generally employed to retain cationic compounds. The complementary information obtained in a triple quadrupole mass spectrometer and in an ion trap Orbitrap has been used to study the fragmentation of the DADMAC cation [M](+) and for the correct assignment of the products ions. The HILIC/MS/MS method developed, using electrospray ionization in positive ion mode and selected reaction monitoring (SRM) acquisition mode, led to a reliable determination and confirmation of the DADMAC cation in water samples down to 50 ng L(-1). The low detection limit achieved, in combination with the absence of matrix effects, allowed the direct analysis of samples without any pretreatment, preconcentration or clean-up step. DADMAC was determined in samples collected in a drinking water treatment plant (DWTP) in Barcelona (Spain) and it was found in the influent at the μg L(-1) level.     

Drugs of abuse and their metabolites in waste and surface waters by liquid chromatography-tandem mass spectrometry

A solid‐phase extraction and liquid chromatography‐tandem mass spectrometry (SPE/LC‐MS‐MS) method was developed and validated for the simultaneous determination of nicotine, five drugs of abuse (morphine, cocaine, codeine, methadone, and 2‐ethylidene‐1,5‐dimethyl‐3,3‐diphenylpyrrolidine) and four metabolites (dihydrocodeine, 6‐acetylmorphine, 11‐nor‐carboxy‐Δ⁹‐tetrahydrocannabinol, and benzoylecgonine) in water samples. A Fused‐Core? particle column was used as an alternative to sub‐2‐μm particles in chromatographic separations to work with low backpressures and high efficiencies in short analysis times. Drugs were extracted from waste and surface water with SPE using Oasis MCX cartridges. Electrospray (ESI) in positive and negative mode and tandem MS selected reaction monitoring mode were used for identification and quantification. Calibration by linear regression analysis with deuterated internal standards was used to compensate the matrix effects. Limits of detection were found as low as 0.5–1 ng/L (surface water) and 1–50 ng/L (wastewater). The method was applied to the analysis of different kinds of samples. Wastewater from a sewage treatment plant was collected from three sampling points (after primary, secondary, and tertiary treatments) for a week. The analysis of the samples revealed a significant presence of these drugs in samples from primary treatments, where maximum concentrations of nicotine (1105 ng/L) and benzoylecgonine (3336 ng/L) were found. Most of the compounds showed values between 相似文献   

液相色谱-串联质谱法测定花生中丙硫菌唑及其脱硫代谢物

建立了液相色谱-串联质谱(HPLC-MS/MS)同时检测花生中丙硫菌唑及其主要代谢物硫酮菌唑的方法.花生样品经乙腈提取后,用乙腈饱和的正己烷除掉脂类杂质,C18分散固相萃取净化样品.采用含有5 mmol/L乙酸铵、0.2％乙酸和乙腈作为流动相进行梯度洗脱,在电喷雾-多反应监测离子模式下进行定性与定量分析.丙硫菌唑和硫酮菌唑在2.0,4.0和20.0 μg/kg的添加浓度时回收率为87.22％～102.46％;相对标准偏差小于10.0％;方法定量限为2.0 μg/kg.     

Determination of endogenous and exogenous estrogens in effluents from sewage treatment plants at the ng/L-level

An analytical method for the determination of the major endogenous and exogenous estrogenic steriods in effluent water samples of sewage treatment plants (STPs) with a LOQ down to 1 ng/L and below has been developed. The exogenous estrogen 17alpha-ethynylestradiol, frequently used as estrogenic component in oral contraceptives, and the endogenous estrogen 17beta-estradiol show the highest estrogenic potential, therefore they were part of our target compounds. In addition, the content of the synthetic gestagen levonorgestrel, also often administered in oral contraceptives, was determined. A solid-phase extraction system for high volume sampling of water up to 25 L was implemented. Two types of adsorbent, Amberlite XAD 2 and a mixture of LiChrolut EN/Bondesil C-18, respectively, were tested for their extraction efficiency of these polar analytes. Recovery rates with LiChrolut EN/Bondesil C-18 ranged up to 94%, whereas sampling on XAD 2 led only to poor recoveries below 40%. After a liquid chromatographic clean-up step on silicagel the steroids were converted into their trimethylsilyl-ethers by the reaction with MSTFA/TMSI (N-methyl-N-trimethylsilyl-2,2,2-trifluoroacetamide, trimethylsilyliodide) and were then determined by HRGC/MS in the selected ion mode. A limit of quantification over the whole procedure of at least 1 ng/L was reached for all analytes. In several effluent samples the input of estrogens by the STP of the cities Ulm and New Ulm into the river Danube was characterised. The concentrations commonly found ranged from 1 ng/L up to 13 ng/L, depending on the respective steroid.     

Determination of antihypertensive and anti-ulcer agents from surface water with solid-phase extraction-liquid chromatography-electrospray ionization tandem mass spectrometry

Pharmaceuticals are emerging contaminants in surface water and they must be measured to follow their effects on the aquatic environment. We developed a solid-phase extraction and liquid chromatography-electrospray ionization tandem mass spectrometry (SPE-LC-ESI-MS/MS) method for the determination of twenty-six pharmaceutical compounds - which belong to antihypertensive and anti-ulcer agents - from surface water samples. The selection of pharmaceuticals was based on usage frequency in Hungary. During method development Oasis HLB, SampliQ Polymer SCX and Si-SCX SPE cartridges were tested. As LC eluent ammonium formate, ammonium acetate buffers at pH 3 and 5 were investigated and for quantitation both matrix-matched and internal standard calibration was used. For matrix effect assessment post-extraction spike method was applied which can separate the extraction efficiency from ion suppression for better determination of recovery. Method detection limits (MDLs) varied between 0.2 and 10 ng/L. Precision of the method, calculated as relative standard deviation (RSD), ranged from 0.2 to 14.6% and from 1.2 to 22.4% for intra- and inter-day analysis, respectively. The method was applied to analyze Danube water samples. Measured average concentrations varied between 2 and 39 ng/L for eleven compounds and another one could be detected under LOQ.     

Application of dispersive liquid–liquid microextraction followed by HPLC–MS/MS for the trace determination of clotrimazole in environmental water samples

A method for the analysis of clotrimazole was developed with dispersive liquid–liquid microextraction for sample pre‐concentration and HPLC–MS/MS for analysis. A linear ion trap was used for the confirmation of clotrimazole identity in the samples. The developed method enables the analysis of clotrimazole in river water and sewage effluent from wastewater treatment plants with a LOQ of 0.7 ng/L. Environmental monitoring of clotrimazole was undertaken. Samples from river water and sewage effluents were analysed over a one‐year period. Clotrimazole was found in every tested sample with concentration range from 1 to 31 ng/L. The amount of clotrimazole in tested samples was highly dependent on sampling season. The highest results were obtained in summer and autumn.