Multiresidue method for the analysis of emerging contaminants in wastewater by ultra performance liquid chromatography-time-of-flight mass spectrometry

A multiresidue method for screening of emerging contaminants in aquatic environments was developed. The method was based on sample pretreatment with solid phase extraction (SPE) and analysis with an ultra performance liquid chromatograph-time-of-flight mass spectrometer (UPLC-TOF-MS). The method was optimized and tested with standard solutions of model compounds containing 84 pesticides and pharmaceuticals. Four different SPE sorbents were evaluated to gain maximum recovery for the analytes. For the final procedure a combination of two different sorbents was chosen. In spite of high matrix suppression, the method quantification limits (MQLs) were acceptable. Therefore, the method can be used for screening known target compounds. The applicability of the method for posttarget and nontarget screening will be reported later. To preliminarily assess the quantitative performance of the method, some compounds in wastewater effluent were quantified using the standard addition method. Three pesticides and eight pharmaceuticals were found in concentrations up to ～2200 ng/L.     

A simple,fast method for the analysis of 20 contaminants of emerging concern in river water using large-volume direct injection liquid chromatography-tandem mass spectrometry

Analytical and Bioanalytical Chemistry - A fast and sensitive method for the determination of a structurally and physico-chemically diverse group of contaminants of emerging concern (CEC) based on...     

基于色谱-质谱联用的新型有机污染物分析方法与技术

新型有机污染物是目前国内外关注的热点。在发现和分析新型有机污染物方面色谱-质谱联用技术发挥着至关重要的作用。本文对5类新型有机污染物(全氟化合物、药物、饮用水消毒副产物、农药转化产物和新农药、溴化阻燃剂)的主要色谱-质谱联用技术进行了介绍和评价,并对色谱-质谱联用的发展趋势进行了展望。     

Development of a multiresidue method for the determination of multiclass pesticides in soil using GC

The principal objective of the present study was to develop a multiresidue analytical method for 62 pesticides in a soil matrix. Soil samples were fortified with known quantities of pesticides at two different concentration levels (0.1 and 0.01 μg/g) and the analytes were extracted via a liquid–solid extraction method. The pesticides were separated on an HP5 capillary column and were detected by gas chromatography coupled to an electron capture detector (GC‐ECD). The method was validated, considering its good linearities (r² = 0.978–0.999), specificity and recovery characteristics. Recoveries were found between 70.3 and 113.4% for all pesticides except edifenphos (67.5%) and dichlobenil (69.5%) spiked at a 0.1 μg/mL concentration level and 74.5–117% except ethalfluralin (63.3%) and dichlobenil (51.9%) spiked at a concentration of 0.01 μg/mL. The developed method could be utilized as a simple and cost‐effective method for the routine analysis of 62 pesticides in soil samples. Copyright © 2009 John Wiley & Sons, Ltd.     

Development of an economic ultrafast liquid chromatography with tandem mass spectrometry method for trace analysis of multiclass mycotoxins in Polygonum multiflorum

Rapid, economic, and highly effective determination of multiple mycotoxins in complex matrices has given huge challenges for the analytical method. In this study, an economic analytical strategy based on sensitive and rapid ultrafast liquid chromatography coupled to hybrid triple quadrupole/linear ion trap mass spectrometry technique was developed for the determination of seven mycotoxins of different chemical classes (aflatoxin B₁, B₂, G₁, and G₂, ochratoxin A, T‐2 toxin, and HT‐2 toxin) in Polygonum multiflorum. Target mycotoxins were completely extracted using a modified quick, easy, cheap effective, rugged, and safe method without additional clean‐up steps. The types of extraction solvents and adsorbents for the extraction procedure were optimized to achieve high recoveries and reduce coextractives in the final extracts. Due to significant matrix effects for all analytes (≤68.9% and ≥110.0%), matrix‐matched calibration curves were introduced for reliable quantification, exploring excellent linearity for the seven mycotoxins with coefficients of determination >0.9992. The method allowed high sensitivity with limit of detection in the range of 0.031–2.5 μg/kg and limit of quantitation in the range of 0.078–6.25 μg/kg, as well as satisfactory precision with relative standard deviations lower than 8%. Recovery rates were between 74.3 and 119.8% with relative standard deviations below 7.43%. The proposed method was successfully applied for 24 batches of P. multiflorum samples, and six samples were found to be positive with aflatoxin B₁, B₂, G₁, or ochratoxin A. The method with significant advantages, including minimum analytical time, low time and solvent consumption, and high sensitivity, would be a preferred candidate for economic analysis of multiclass mycotoxins in complex matrices.     

Development of a high‐throughput method based on thin‐film microextraction using a 96‐well plate system with a cork coating for the extraction of emerging contaminants in river water samples

In this study, a new method was developed in which a biosorbent material is used as the extractor phase in conjunction with a recently described sample preparation technique called thin‐film microextraction and a 96‐well plate system. The method was applied for the determination of emerging contaminants, such as 3‐(4‐methylbenzylidene) camphor, ethylparaben, triclocarban, and bisphenol A in water samples. The separation and detection of the analytes were performed by high‐performance liquid chromatography with diode array detection. These contaminants are considered hazardous to human health and other living beings. Thus, the development of an analytical method to determine these compounds is of great interest. The extraction parameters were evaluated using multivariate and univariate optimization techniques. The optimum conditions for the method were 3 h of extraction time, 20 min of desorption with 300 μL of acetonitrile and methanol (50:50, v/v), and the addition of 5% w/v sodium chloride to the sample. The analytical figures of merit showed good results with linear correlation coefficients higher than 0.99, relative recoveries of 72–125%, interday precision (n = 3) of 4–18%, and intraday precision (n = 9) of 1–21%. The limit of detection was 0.3–5.5 μg/L, and the limit of quantification was 0.8–15 μg/L.     

Cellulose membrane modified with polypyrrole as an extraction device for the determination of emerging contaminants in river water with gas chromatography–mass spectrometry

In this study, a simple, efficient, and reusable device based on cellulose membranes modified with polypyrrole was developed to extract 14 emerging contaminants from aqueous matrices. For chemical polymerization, a low‐cost cellulose membrane was immersed in 0.1 mol/L pyrrole and 0.5 mol/L ammonium persulfate for 40 min in an ice/water bath. The cellulose membranes modified with polypyrrole were accommodated in a polycarbonate holder suitable for solid‐phase extraction disks. Solid‐phase extraction parameters that affect extraction efficiency, such as sample volume, pH, flow rate, and desorption were optimized. Subsequently, determination of target compounds was performed by gas chromatography with mass spectrometry. The linear range for analytes ranged from 0.05 to 500 μg/L, with coefficients of determination above 0.990. The limits of quantification varied between 0.05 and 10 μg/L, with relative standard deviations lower than 17%. The performance of the proposed cellulose membranes modified with polypyrrole device for real samples was evaluated after extraction of emerging contaminants from a river water sample from the city of Curitiba, Brazil. Bisphenol A (6.39 μg/L), caffeine (17.83 μg/L), and paracetamol (19.28 μg/L) were found in these samples.     

Development of an ultra-performance liquid chromatography-mass spectrometry method for the detection of lipophilic marine toxins

A rapid method for the detection of marine toxins was developed using an ultra-performance liquid chromatography (UPLC) system coupled to a latest generation mass spectrometry (MS) system. The analysis of 21 lipophilic marine toxins was achieved on an Acquity C18 column using a water-acetonitrile gradient with a cycle time of 6.6 min, reducing analysis time by more than a factor two compared to HPLC while maintaining peak resolution. Linear ranges, limits of detection and limits of quantification were established for okadaic acid (OA), pectenotoxin-2, azaspiracid-1 (AZA1), yessotoxin, gymnodimine and 13-desmethylspirolide C. The method was found to be accurate when using a triplicate methanolic extraction. Matrix effects were assessed by standard addition of OA and AZA1 in extracts of raw and heat-treated flesh of mussels and oysters. For the analysis of AZA1, the UPLC-MS method was always prone to signal suppression, while for OA analysis signal suppression was observed in extracts of raw shellfish flesh and signal enhancement in extracts of heat-treated flesh. Matrix effects occurring in the method presented are diminished compared to previous studies.     

Critical evaluation of screening techniques for emerging environmental contaminants based on accurate mass measurements with time‐of‐flight mass spectrometry

Emerging contaminants from wastewater effluent samples were analysed, using posttarget and nontarget analysis techniques. The samples were analysed with an ultra performance liquid chromatograph‐time‐of‐flight mass spectrometer (UPLC‐TOF‐MS), and the resulting data were processed with commercial deconvolution software. The method works well for posttarget analysis with prior information about the retention times of the compounds of interest. With positive polarity, 63 of 66 compounds and with negative polarity, 18 of 20 compounds were correctly identified in a spiked sample, while two compounds of a total of 88 fell out of the mass range. Furthermore, a four‐stage process for identification was developed for the posttarget analysis lacking the retention time data. In the process, the number of candidate compounds was reduced by using the accurate mass of selected compounds in two steps (stages 1 and 2), structure–property relationships (stage 3) and isotope patterns of the analytes (stage 4). The process developed was validated by analysing wastewater samples spiked with 88 compounds. This procedure can be used to gain a preliminary indication of the presence of certain analytes in the samples. Nontarget analysis was tested by applying a theoretical mass spectra library for a wastewater sample spiked with six pharmaceuticals. The results showed a high number of false identifications. In addition, manual processing of the data was considered laborious and ineffective. Finally, the posttarget analysis was applied to a real wastewater sample. The analysis revealed the presence of six compounds that were afterwards confirmed with standard compounds as being correct. Three psycholeptics (nordiazepam, oxazepam and temazepam) could be tentatively identified, using the identification process developed. Posttarget analysis with UPLC‐TOF‐MS proved to be a promising method for analysing wastewater samples, while we concluded that the software for nontarget analysis will need improvement before it can be used in environmental analytical work with LC‐TOF‐MS systems. Copyright © 2012 John Wiley & Sons, Ltd.     

Development of a single‐run analytical method for the detection of ten multiclass emerging contaminants in agricultural soil using an acetate‐buffered QuEChERS method coupled with LC–MS/MS

This study was undertaken to develop and validate a single multiresidue method for the monitoring of ten multiclass emerging contaminants, viz. ceftiofur, clopidol, florfenicol, monensin, salinomycin, sulfamethazine, sulfathiazole, sulfamethoxazole, tiamulin, and tylosin in agricultural soil. Samples were extracted using an acetate‐buffered, modified quick, easy, cheap, effective, rugged, and safe method followed by liquid chromatography with tandem mass spectrometric analysis in positive ion mode. Separation on an Eclipse Plus C₁₈ column was conducted in gradient elution mode using a mobile phase of methanol (A) and distilled water (B), each containing 0.1% formic acid and 5 mM ammonium formate. The linearity of the matrix‐matched calibrations, expressed as determination coefficients, was good, with R ² ≥ 0.9908. The limits of quantification were in the range 0.05–10 μg/kg. Blank soil samples spiked with 4 × and 20 × the limit of quantification provided recovery rates of 60.2–120.3% (except sulfamethoxazole spiked at 4 × the limit of quantification, which gave 131.9%) with a relative standard deviation < 13% (except clopidol spiked at 20 × the limit of quantification, which gave 25.2%). This method was successfully applied to the monitoring of 51 field‐incurred agricultural loamy‐sand soil samples collected from 17 provincial areas throughout the Korean Peninsula. The detected and quantified drugs were clopidol (≤ 4.8 μg/kg), sulfathiazole (≤ 7.7 μg/kg), sulfamethazine (≤ 6.6 μg/kg), tiamulin (≤ 10.0 μg/kg), and tylosin (≤ 5.3 μg/kg). The developed method is simple and versatile, and can be used to monitor various classes of veterinary drugs in soil.     

Development and validation of a multiclass method for the analysis of antibiotic residues in eggs by liquid chromatography-tandem mass spectrometry

A multiclass method for the analysis of residues, in egg matrices, of 41 antimicrobial agents belonging to seven families (sulfonamides, diaminopyridine derivates, quinolones, tetracyclines, macrolides, penicillins and lincosamides) was developed and validated according to the requirements of European Commission Decision 2002/657. Compounds were extracted with a pressurized liquid extraction (PLE) technique using a 1:1 mixture of acetonitrile and a succinic acid buffer (pH 6.0) at 70 °C. As this resulted in clear extracts, no further clean-up was necessary. Analytes were determined by ultra-high-pressure liquid chromatography–tandem mass spectrometry (UHPL–MS/MS) in a chromatographic run of 13 min. Calibration was carried out with spiked blank samples subjected to the entire analytical procedure. Five compounds, two of them isotopically labelled, were used as internal standards. Most analytes were quantified with errors below 10%. Precision in terms of reproducibility standard deviation was between 10% and 20% in most cases. CCα values were in the range 0.5–3.8 μg kg⁻¹ for the non-authorized compounds. The proposed method would enable an experienced analyst to process about 25 samples per day.     

Preconcentration of emerging contaminants in environmental water samples by using silica supported Fe3O4 magnetic nanoparticles for improving mass detection in capillary liquid chromatography

A magnetic material based on Fe(3)O(4) magnetic nanoparticles incorporated in a silica matrix by using a sol-gel procedure has been used to extract and preconcentrate emerging contaminants such as acetylsalicylic acid, acetaminophen, diclofenac and ibuprofen from environmental water samples prior to the analysis with Capillary LC-MS. The use of the proposed silica supported Fe(3)O(4) magnetic nanoparticles enables surfactant free extracts for the analysis with MS detection without interferences in the ionisation step. Under the optimum conditions, we demonstrated the reusability of the magnetic sorbent material during 20 uses without loss in the extraction efficiency. In addition, no cleanup was necessary. The preconcentration factor was 100 and the detection limits were between 50 and 150 ng/L. The proposed procedure has been applied to the analysis of water samples obtaining recoveries between 80 and 110% and RSD values lower than 12%. Concentrations of the target analytes over the range 1.7 and 0.1 μg/L have been found in different water samples.     

A natural and renewable biosorbent phase as a low‐cost approach in disposable pipette extraction technique for the determination of emerging contaminants in lake water samples

This study proposes an efficient analytical methodology using a biosorbent (cork) as an extraction phase in disposable pipette extraction technique for the rapid determination of the emerging contaminants methyl paraben, ethyl paraben, benzophenone, 3‐(4‐methylbenzylidene) camphor and 2‐(ethylhexyl)‐4‐(dimethylamino) benzoate in lake water samples using high‐performance liquid chromatography with diode array detection. The optimized conditions were comprised of 800 μL of sample, three cycles of 30 s each for the extraction, pH 6, addition of 30% w/v of NaCl. For the desorption step, the optimized desorption conditions were achieved with 100 μL of a mixture comprised of 50% methanol and 50% acetonitrile v/v, using one cycle of 30 s. Excellent analytical performance was achieved with limits of detection of 0.6 μg/L for methyl paraben to 1.4 μg/L for 3‐(4‐methylbenzylidene) camphor, and the limit of quantitation varied from 2 μg/L for methyl paraben to 4.3 μg/L 3‐(4‐methylbenzylidene) camphor, respectively. The correlation coefficients ranged from 0.9962 for ethyl paraben to 0.9980 for methyl paraben. The method accuracy varied from 71–132%, and the intraday precision ranged from 3 to 23% (n = 3) and interday from 9 to 23% (n = 9). The robustness was evaluated through Youden and Lenth's methods and indicated no significant variations in the results.     

Development and validation of a liquid chromatography-mass spectrometry method for the determination of 4,5-diazafluoren-9-one

A new liquid chromatography-mass spectrometry (LC-MS) method is developed and validated for the identification and determination of novel 4,5-diazafluoren-9-one compound. The method employs a Waters XTerra RP-18 column (150 mmx4.6 mm, i.d. 5 microm) with a mobile phase comprised of a (50:50, v/v) mixture of deionized water containing 0.2% acetic acid (solvent A) and methanol (solvent B) at a flow rate of 1 mL/min, at 35 degrees C. The detection is performed with photodiode-array (PDA) set at 210-400 nm and single quadropole mass spectrometer with electrospray ionization (ESI) positive ion mode. The chromatographic separation is achieved in less than 3 min. The linearity is established over the concentration range of 0.1-0.5 mg/mL (r2=1.000). The mean RSD values for intra- and inter-day precision studies are <2%. The recovery of 4,5-diazafluoren-9-one ranged between 99.84 and 99.97%. The limits of detection and quantitation are determined to be 0.58 and 0.1 mg/mL, respectively.     

Comparison of several extraction techniques for multiclass analysis of veterinary drugs in eggs using ultra-high pressure liquid chromatography-tandem mass spectrometry

This study compared four extraction methods for the simultaneous determination of tetracyclines, macrolides, quinolones, sulphonamides and anthelmintics (including benzimidazoles and avermectins) in eggs by ultra-high pressure liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). Solvent extraction, solid-phase extraction (SPE), matrix solid-phase dispersion (MSPD) and modified QuEChERS procedure were compared in terms of recovery and number of veterinary drugs extracted. The solvent extraction procedure with a clean-up step provided better results than the other tested procedures. The QuEChERS procedure was simpler and faster, but extracted fewer compounds than solvent extraction. MSPD did not extract tetracyclines and quinolones, whereas macrolides and tetracyclines were not extracted when SPE was applied. The solvent extraction procedure was validated, obtaining recoveries ranging from 60% (sulfaquinoxaline) to 119% (levamisole) with repeatability values (expressed as relative standard deviations, RSDs) lower than 20% at two concentration levels (10 and 100 μg kg⁻¹), except for erythromycin, emamectin and ivermectin that showed RSD values close to 25% at 10 μg kg⁻¹. Limits of quantification (LOQs) were always equal or lower than 5 μg kg⁻¹. Finally the method was applied to egg samples, and erythromycin, enrofloxacin, difloxacin, thiabendazole, emamectin and fenbendazole were detected in four samples.     

Evaluation of a new carbon/zirconia‐based sorbent for the cleanup of food extracts in multiclass analysis of pesticides and environmental contaminants

A novel carbon/zirconia‐based material, Supel^TM QuE Verde, was evaluated in a filter‐vial dispersive solid‐phase extraction cleanup of pork, salmon, kale, and avocado extracts for the residual analysis of 65 pesticides and 52 environmental contaminants (flame retardants, polychlorinated biphenyls, polybrominated diphenyl ethers, and polycyclic aromatic hydrocarbons) using low‐pressure gas chromatography with tandem mass spectrometry. An amount of 180 mg sorbent per 0.6 mL extract in filter‐vial dispersive solid‐phase extraction cleanup was found the optimum in terms of achieving satisfactory removal of co‐extractives and recoveries of analytes, especially for structurally planar compounds. For analytes partially retained by Verde, normalization to an internal standard resulted in 62–107% recoveries. Addition of Verde to primary secondary amine and C₁₈ in cleanup resulted in 38% more removal of gas‐chromatography‐amenable co‐extractives in avocado, 30% in kale, 39% in salmon, and 50% in pork. The removal efficiency of co‐extracted chlorophyll was 93% for kale and 64% for avocado based on ultraviolet‐visible absorbance. The developed method was validated at three spiking levels (10, 25, and 100 ng/g), and 70–120% recoveries with ≤20% relative standard deviation were achieved for 96 (83%) out of 117 analytes in pork, 79 (69%) in salmon, 71 (62%) in kale, and 75 (65%) in avocado.     

Multi-residue ultra-performance liquid chromatography coupled with tandem mass spectrometry method for comprehensive multi-class anthropogenic compounds of emerging concern analysis in a catchment-based exposure-driven study

Analytical and Bioanalytical Chemistry - This paper presents a new multi-residue method for the quantification of more than 142 anthropogenic compounds of emerging concern (CECs) in various...     

A new gas chromatography/mass spectrometry method for the simultaneous analysis of target and non-target organic contaminants in waters

In this study we developed a GC–MS method for the analysis of priority pollutants, personal care products (PCPs) and other emerging contaminants in waters using large volume injection with backflushing. Analyses are performed in the SIM/scan mode, so that in addition to the targeted organic contaminants, this method allows the simultaneous screening of non-target compounds. The scan data are analysed using Deconvolution Reporting Software (DRS) which screens the results for 934 organic contaminants. Deconvolution helps identify contaminants that are buried in the chromatogram by co-extracted materials and significantly reduces chromatographic resolution requirements, allowing shorter analysis times. All compounds have locked retention times and we can continually update and extend the mass spectral library including new compounds. Linearity and limits of detection in SIM and full-scan mode were studied. Method detection limits (MDLs) in effluent wastewater ranged in most of the cases from 1 to 36 ng/L in SIM mode and from 4 to 66 ng/L in full-scan mode; while in river water from 0.4 to 14 and 2–29 ng/L in SIM and full-scan mode, respectively. We obtained a linearity of the calibration curves over two orders of magnitude. The method has been applied to the screening of a large number of organic contaminants – not only to a subset of targets – in urban wastewaters from different wastewater treatment plants and also in river waters. Most of the target compounds were detected at concentration levels ranging from 11 to 8697 ng/L and from 7 to 1861 ng/L in effluent wastewater and river waters, respectively. Additionally, a group of 12 new compounds were automatically identified using the AMDIS and NIST libraries. Other compounds, such as the 4-amino musk xylene, a synthetic fragrance metabolite, which was not included in the databases, but has been manually searched in the full-scan chromatograms.     

基于气相色谱-质谱联用与液相色谱-质谱联用的非靶向代谢组学用于3类茶叶中化学成分分析（英文）

茶叶中的化学成分是构成其风味特征的物质基础。本研究建立了基于气相色谱-质谱联用和液相色谱-质谱联用的非靶向代谢组学方法。完成预处理及分析条件优化后,使用标准样品考察方法的线性、回收率及重复性,结果表明方法整体稳定且结果可靠。将该方法用于绿茶、乌龙茶和红茶中化学成分的分析。通过超声辅助溶剂提取及气相色谱-质谱联用分析共获得1812个特征峰,而使用加热溶剂提取及液相色谱-质谱联用分析可获得2608个特征峰。结合保留规律及质谱数据库,共定性173种化合物(109种随后经标准样品验证),其中只有9种化合物在上述两类分析中被同时检出,表明方法互补性良好。3类茶叶数据的偏最小二乘判别分析结果表明,三者间存在显著差异。结合模型的变量重要因子(VIP)与非参数检验共筛选出90种化合物,其中包含儿茶素、氨基酸、糖、有机酸和黄酮苷类等众多与茶叶滋味密切相关的化学成分。     

Comprehensive analysis system using liquid chromatography-mass spectrometry for the biosynthetic study of peptides produced by cyanobacteria

Microcystins are hepatotoxic heptapeptides and general tumor promoters produced by several species of the genera Microcystis, Anabaena, Oscillatoria and Nostoc. They are non-ribosomally synthesized via a mixed polyketide synthase/non-ribosomal peptide synthetase system called microcystin synthetase. We have carried out the detection, isolation and structural determination of non-toxic peptides produced together with microcystins by toxic cyanobacteria, which are classified into several groups on the basis of their structures and some of these non-toxic peptides are also non-ribosomally synthesized as well as microcystins. In the present study, we tried to correlate the secondary metabolic peptides produced by the hepatotoxic cyanobacteria with the corresponding peptide synthetase genes. An analytical method using LC-electroscopy ionization MS and photodiode array detection was developed for the exhaustive screening of cyanobacterial peptides in Japanese strains and it was successfully applied to the peptide fractions extracted from these strains. The established method was advantageous over conventional ones using the usual HPLC and matrix-assisted laser desorption ionization time-of-flight MS, because more structural information could be obtained and it is easier to distinguish microcystins from other peptides using this method. Small amounts of other peptides could also be detected by this method. The established method will contribute to the investigation of the relationship between genes encoding the peptide synthetase and secondary metabolic peptides.