Determination of alkylphenols and alkylphenol carboxylates in wastewater and river samples by hemimicelle-based extraction and liquid chromatography-ion trap mass spectrometry

Sodium dodecyl sulfate (SDS)-coated alumina and cetylpyridinium chloride (CPC)-coated silica were investigated as new sorbents for the concentration of alkylphenol polyethoxylate (APE) biodegradation products from wastewater and river water samples. Octylphenol (OP), nonylphenol (NP), octylphenol carboxylic acid (OPC) and nonylphenol carboxylic acid (NPC) were quantitatively retained on both supramolecular sorbents on the basis of the formation of mixed hemimicelles and admicelles. SDS hemimicelles-based SPE was proposed for the extraction/concentration of the target compounds prior to their separation and quantitation by liquid chromatography/electrospray ionization in negative mode, ion trap mass spectrometry. No clean-up steps or evaporation of the eluent were required. The recovery of APE metabolites from sewage and river water ranged between 87 and 100%. Concentration factors of about 500, using sample volumes of 1 l, were achieved. Detection limits were between 75 and 193 ng/l. The approach developed was applied to the determination of alklylphenols and alkylphenol carboxylic acids in raw and treated sewage and river samples. The concentrations of APE metabolites found ranged between 0.8 and 78 microg/l.     

Determination of nonylphenol ethoxylate oligomers by liquid chromatography-electrospray mass spectrometry in river water and non-ionic surfactants

Liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) for the quantitative determination of five nonylphenol ethoxylate (NPE) oligomers in river water was described. These NPE oligomers were separated on a poly(vinyl alcohol) gel column using acetonitrile-30 mM ammonium acetate as the mobile phase followed by ESI-MS detection without any sample concentration steps. The sample was only filtered using the disposable filter and the aliquot (100 micro1) of this sample was injected into the LC-ESI-MS system. All NPE oligomers were detected using the [M+NH4]-ion. Detection limits ranged from 160 pg/ml (NPE4) to 240 pg/ml (NPE2), repeatability and reproducibility ranged from 4.2% (NPE2) to 6.2% (NPE6) and from 7.4% (NPE5) to 9.8% (NPE6).     

Determination of perfluorinated compounds in wastewater and river water samples by mixed hemimicelle-based solid-phase extraction before liquid chromatography-electrospray tandem mass spectrometry detection

A comparative study on the use of cetyltrimethylammonium bromide (CTAB)-coated silica and sodium dodecyl sulphate (SDS)-coated alumina mixed hemimicelles-based solid-phase extraction (SPE) for the pre-concentration of six perfluorinated compounds (PFCs) in environmental water samples was presented. The six analytes heptafluorobutyric acid (HFBA), perfluoroheptanic acid (PFHeA), perfluorooctanic acid (PFOA), perfluorooctanic sulfonic (PFOS), perfluorononanic acid (PFNA) and perfluorodecanic acid (PFDeA) were quantitatively retained on both sorbent materials. The cationic surfactant (CTAB adsorbed onto silica) was more appropriate for SPE of PFCs. The main factors affecting adsolubilization of PFCs including the amount of surfactant, pH of solution, sample loading volume and desorption were investigated and optimized. Concentration factor of 500 were achieved by SPE of 500 mL of several environmental water samples. The method detection limits obtained for HFBA, PFHeA, PFOA, PFOS, PFNA and PFDeA were 0.10, 0.28, 0.07, 0.20, 0.10 and 0.05 ng/L, respectively. The relative standard deviation of recoveries ranged from 2 to 8%, which indicated good method precision.     

Determination of cannabinoids in cannabis products using liquid chromatography-ion trap mass spectrometry

A method was developed and validated for the simultaneous determination of five cannabinoids, viz. cannabidiol (CBD), cannabidiol acid (CBD-COOH), cannabinol (CBN), delta9-tetrahydrocannabinol (THC), and 3'-carboxy-delta9-all-trans-tetrahydrocannabinol (THC-COOH) in cannabis products. The cannabinoids were extracted from the grinded cannabis samples with a mixture of methanol-chloroform and analysed using liquid chromatography with ion-trap-mass-spectrometry (LC-IT-MSn). For quantification the two most abundant diagnostic MS-MS ions of the analyte in the sample and external standard were monitored. For confirmation purposes the EU criteria as described in Commission Decision 2002/657/EC were followed. Fully satisfactory results were obtained, that is, unequivocal confirmation according to the most stringent EU criteria was possible. The limits of quantification were 0.1 g/kg for CBD, 0.04 g/kg for CBD-COOH, 0.03 g/kg for CBN, 0.28 g/kg for THC and 9.9 g/kg for THC-COOH. The repeatabilities, defined by R.S.D., were 2% for CBN, THC and THC-COOH at the concentration levels of respectively 0.023, 3.3 and 113 g/kg and 5% for CBD-COOH at the level of 0.34 g/kg (n = 6).     

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.     

Determination of interfering triazine degradation products by gas chromatography-ion trap mass spectrometry

Deethylatrazine (DEA), an atrazine degradation product, has been added to the US Environmental Protection Agency's Drinking Water Contaminant Candidate List (CCL). In its gas chromatographic analysis, DEA can coelute with deisopropylatrazine (DIA), another degradation product. The present work demonstrates that the coelution of DEA and DIA can induce a significant (up to approximately 50%) positive bias in the DEA determination, when using an ion-trap mass spectrometer as the detector. The DIA determination is unaffected by the coelution within experimental error. This may be explained in terms of gas-phase ion fragment populations. A correction factor to the observed DEA concentration may be developed based on the measured DIA concentration.     

气相色谱-离子阱质谱联用测定玩具中21种致敏性芳香剂

建立了气相色谱-离子阱质谱联用测定布绒、贴纸和塑料玩具中苯甲醇等21种致敏性芳香剂的方法。对于布绒和贴纸玩具样品,采用丙酮超声振荡提取20 min后过0.45 μm滤膜,经HP-1MS色谱柱(50 m×0.2 mm×0.5 μm)分离,离子阱质谱检测。对于塑料玩具样品,采取溶解-沉淀方式提取,经Envi-carb石墨化碳固相萃取小柱净化,旋蒸、氮吹浓缩,过0.45 μm滤膜后进行测定,外标法定量。方法对不同物质的定量限(LOQ)为0.02～40 mg/kg,线性范围为0.002～50 mg/L,低、中、高3个添加水平的平均回收率为82.2%～110.8%,相对标准偏差(RSD)为0.6%～10.5%。该方法准确、灵敏,可用于玩具中苯甲醇等21种致敏性芳香剂含量的检测。     

Impurity analysis of gentamicin bulk samples by improved liquid chromatography-ion trap mass spectrometry

Several gentamicin bulk samples from different origins were investigated using an LC/MS method.LC equipped with ion trap MS with positive ionization was performed on a Capcell Pak C18(AQ) column with the mobile phase containing 50 mM trifluoroacetic(TFA) and methanol.Impurities present in batches of gentamicin bulk samples were elucidated and compared according to their fragmentation behavior.In total seventeen impurities present in samples,five impurities were not elucidated and two compounds were identifi...     

Rapid quantification of sucrose esters in oriental tobacco by liquid chromatography-ion trap mass spectrometry

A rapid and sensitive LC-MS/MS method was developed for the quantitative determination of sucrose esters (SEs) in Oriental tobacco samples. The sample preparation involved a 10-min sonication extraction procedure with acetone and five-fold dilution of the extract with methanol. The experiment was carried out in positive ion mode by ESI IT mass spectrometer. Because of lack of authentic standards of SEs, sucrose octa-acetate (internal standard, IS) was used as a surrogate to validate the proposed method. Matrix-matched standard calibration was used for quantification of IS in the spiked samples. Under optimized MS/MS conditions, an LOQ of 3.9 microg/g was achieved for IS, with an LOD of about 1.2 microg/g. Recoveries for IS were 95-97%. Among 19 monitored SEs, the contents of 11 SEs had RSDs lower than 13.7%. The method, with very little sample handling and good sensitivity, was applied to the rapid quantification of SEs in four Oriental tobacco samples. It appears that the sum of contents of the five SEs with MW 650, 664, and 678 Da occupied approximately 80% of the total content of SEs.     

Identification of photocatalytic degradation products of non-ionic polyethoxylated surfactants in wastewaters by solid-phase extraction followed by liquid chromatography-mass spectrometric detection

The photodegradation of non-ionic surfactants (nonylphenol- and alcohol-polyethoxylates, NPEOx and CnEOx) was investigated in different waters with and without a photoinducter (Fe(III)). Deionized water and industrial effluent spiked at 0.5 mg/L with C10EO6 and NPEO9 were irradiated using a xenon arc lamp. Aliquots of the test solutions were taken at different time intervals and were preconcentrated using solid phase extraction (SPE) with C18 cartridges. Liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (LC-APCI-MS) was used to identify the chemical species generated from phototransformation of non-ionic surfactants. The intermediates detected included nonylphenol diethoxylate (NPEO2) and nonylphenol ethoxy acetic acid (NPE2C). Much smaller amounts of degradation products of NPEO9 having only the alkyl chain carboxylated were also formed in the photocatalysis experiment. The identified C10EO6 photoproducts included fatty alcohols and acids. Polyethylene glycols (PEGs) were also formed as the consequence of the central scission of C10EO6 and the deethoxylation of NPEO9. The photodegradation in wastewater samples was more efficient than in deionized water being the half-life (t(1/2)) of C10EO6, 48 h and 29 h in deionized water and wastewater, respectively, and for NPEO9, 17 h and 14 h in deionized water and wastewater, respectively. When induced photodegradation was undertaken, the t(1/2) for NPEO9 was 21 min and 29 min in deionized water and wastewater, respectively. Disappearance of parent compounds was observed after 120 h from the beginning of the photodegradation experiment, or after 210 min of irradiation for the photocatalysis.     

Identification of photocatalytic degradation products of non-ionic polyethoxylated surfactants in wastewaters by solid-phase extraction followed by liquid chromatography-mass spectrometric detection

The photodegradation of non-ionic surfactants (nonylphenol- and alcohol-polyethoxylates, NPEO_x and C_nEO_x) was investigated in different waters with and without a photoinducter (Fe(III)). Deionized water and industrial effluent spiked at 0.5 mg/L with C₁₀EO₆ and NPEO₉ were irradiated using a xenon arc lamp. Aliquots of the test solutions were taken at different time intervals and were preconcentrated using solid phase extraction (SPE) with C₁₈ cartridges. Liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (LC-APCI-MS) was used to identify the chemical species generated from phototransformation of non-ionic surfactants. 2 ) and nonylphenol ethoxy acetic acid (NPE₂C). Much smaller amounts of degradation products of NPEO₉ having only the alkyl chain carboxylated were also formed in the photocatalysis experiment. The identified C₁₀EO₆ photoproducts included fatty alcohols and acids. Polyethylene glycols (PEGs) were also formed as the consequence of the central scission of C₁₀EO₆ and the deethoxylation of NPEO₉. The photodegradation in wastewater samples was more efficient than in deionized water being the half-life (t_1/2) of C₁₀EO₆, 48 h and 29 h in deionized water and wastewater, respectively, and for NPEO₉, 17 h and 14 h in deionized water and wastewater, respectively. When induced photodegradation was undertaken, the t_1/2 for NPEO₉ was 21 min and 29 min in deionized water and wastewater, respectively. Disappearance of parent compounds was observed after 120 h from the beginning of the photodegradation experiment, or after 210 min of irradiation for the photocatalysis. Received: 27 September 2000 / Revised: 11 January 2001 / Accepted: 14 January 2001     

气相色谱-离子阱质谱联用测定玩具中8种酯类致敏性芳香剂

建立了气相色谱-离子阱质谱联用测定玩具中丙烯酸乙酯等8种酯类致敏性芳香剂的方法。对于布绒和贴纸玩具样品,采用丙酮超声提取20 min后过0.45μm滤膜直接进样,对于塑料玩具样品,经相应溶剂提取,离心后,澄清溶液经Envi-carb石墨化碳固相萃取小柱净化,丙酮定容,过0.45μm滤膜后通过30 m HP-5 MS色谱柱分离,质谱进行检测,外标法定量。方法对于不同物质的定量限(LOQ)在0.05～8.0 mg/kg之间,线性范围为0.005～50 mg/L,在3个添加水平的平均回收率在80.2%～105.9%之间,RSD在0.7%～8.9%之间。该方法可用于玩具中丙烯酸乙酯等8种酯类致敏性芳香剂的检测。     

超快速液相色谱-离子阱飞行时间质谱法测定肉制品中10种碱性染料

建立了肉制品中10种碱性染料的超快速液相色谱-离子阱飞行时间质谱(LC-IT-TOF-MS)检测方法。使用Waters AcquityTM UPLC BEH C18(100 mm×2.1 mm,1.7 μm)作为分析柱,以5 mmol/L乙酸铵水溶液-含0.1%(体积分数)甲酸的乙腈溶液为流动相进行梯度洗脱,流速0.2 mL/min。采用电喷雾离子化源,在正离子模式下进行检测。样品用乙腈提取,经弱阳离子交换(Oasis WCX)固相萃取柱净化,超快速液相色谱分离,外标法定量。结果表明,10种碱性染料在1.0～100.0 μg/L范围内线性关系良好,r2均大于0.9915,相对标准偏差(n=7)均小于8.54%。在2,10,25 μg/kg 3个添加水平下平均回收率为65.39%～119.18%。该方法简单、灵敏度高、分析时间短,适用于肉制品中多种碱性染料的同时测定。     

Analysis of pesticides in fruits by pressurized liquid extraction and liquid chromatography-ion trap-triple stage mass spectrometry

A multi-residue method using pressurized liquid extraction (PLE) and liquid chromatography-quadrupole ion trap-triple stage mass spectrometry (LC-IT-MS(3)) has been developed for determining trace levels of pesticides in fruits. The selected pesticides can be distinguished in: benzimidazoles and azoles, organophosphorus, carbamates, neonicotinoids, and acaricides. PLE has been optimized to extract these pesticide residues from oranges and peaches by studying the effect of experimental variables on PLE efficiency. Samples were extracted at high temperature and pressure (75 degrees C and 1500psi) using ethyl acetate as extraction solvent and acidic alumina as drying agent. The recoveries obtained by PLE ranged from 58% to 97% and the relative standard deviation (RSDs) from 5% to 19%. The limits of quantification (LOQs) of the compounds were from 0.025 to 0.25mgkg(-1), which are well-below the maximum residue limits (MRLs) established by the European Union (EU) and the Spanish legislations.     

Determination of sulfonylurea herbicides in water using solid-phase extraction followed by liquid chromatography with electrospray ion trap mass spectrometry

A method has been developed for confirmation and quantitation of ten sulfonylurea herbicides (nicosufuron, thifensulfuron-methyl, metsulfuron-methyl, sulfometuron-methyl, chlorsulfuron, ethametsulfuron-methyl, tribenuron, bensulfuron-methyl, pyrazosulfuron-ethyl and chlorimuron-ethyl) in water samples. Herbicides were extracted from water by off-line solid-phase extraction (SPE). Different types of absorbents were evaluated: silica-based ODS-C₁₈ and two polymeric sorbents, Cleanert HXN and Oasis HLB. Analyte determination and quantitation was performed by liquid chromatography with electrospray mass spectrometry (LC-ESI-MS) instrumentation, equipped with ion trap mass filter. Confirmatory analysis was carried out by LC/MS/MS. MS data acquisition was performed by a single or two-ion extracted ion monitoring program. The ten herbicides were measured in fortified tap water. Average recoveries of the nine analytes (except for tribenuron) from water samples were in the range of 77–109%, and the RSD ranged from 0.3 to 14.5%. The limit of detections (LODs) varied from 6 to 34.8 ng/L.     

Identification and quantification of oleanolic acid and ursolic acid in Chinese herbs by liquid chromatography-ion trap mass spectrometry

A rapid and sensitive method for the identification and quantification of ursolic acid (UA) and oleanolic acid (OA) in Chinese herbs is described. The method combines liquid chromatography (LC) with ion trap‐mass spectrometry (IT‐MS) detection. The UA and OA standard solution were directly infused into IT‐MS for collecting MSⁿ spectra. The major fragment ions of UA and OA were confirmed by MSⁿ at m/z 455, 407, 391, 377 and 363 in negative ion mode, and m/z 457, 439, 411 and 393 in positive mode, respectively. The possible main cleavage pathway of fragment ions was studied. UA and OA provided good signals corresponding to the deprotonated molecular ion [M − H]⁻. The method is reliable and reproducible, and the detection limit is 5 ng/mL. The method was validated in the concentration range of 0.04–40 μg/mL; intra‐ and inter‐day precisions ranged from 0.78 to 2.15%, and the accuracy was 96.5–108.2% for UA and OA. The mean recovery of UA and OA was 97.1–106.2% with RSD less than 1.86%. An LC‐IT‐MS method was successfully applied to determine the UA and OA in nine Chinese herbs. Copyright © 2011 John Wiley & Sons, Ltd.     

Simultaneous screening and confirmation of multiple classes of drug residues in fish by liquid chromatography-ion trap mass spectrometry

LC-ion trap mass spectrometry was used to screen and confirm 38 compounds from a variety of drug classes in four species of fish: trout, salmon, catfish, and tilapia. Samples were extracted with acetonitrile and hexane. The acetonitrile phase was evaporated, redissolved in water and acetonitrile, and analyzed by gradient chromatography on a phenyl column. MS² or MS³ spectra were monitored for each compound. Qualitative method performance was evaluated by the analysis over several days of replicate samples of control fish, fish fortified with a drug mixture at 1 ppm, 0.1 ppm and 0.01 ppm, and fish dosed with a representative from each drug class. Half of the 38 drugs were confirmed at 0.01 ppm, the lowest fortification level. This included all of the quinolones and fluoroquinolones, the macrolides, malachite green, and most of the imidazoles. Florfenicol amine, metronidazole, sulfonamides, tetracyclines, and most of the betalactams were confirmed at 0.1 ppm. Ivermectin and penicillin G were only detectable in the 1 ppm fortified samples. With the exception of amoxicillin, emamectin, metronidazole, and tylosin, residue presence was confirmed in all the dosed fish.     

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.     

Determination of triazine herbicides in aqueous samples by dispersive liquid-liquid microextraction with gas chromatography-ion trap mass spectrometry

A simple and rapid new dispersive liquid-liquid microextraction technique (DLLME) coupled with gas chromatography-ion trap mass spectrometric detection (GC-MS) was developed for the extraction and analysis of triazine herbicides from water samples. In this method, a mixture of 12.0 microL chlorobenzene (extraction solvent) and 1.00 mL acetone (disperser solvent) is rapidly injected by syringe into the 5.00 mL water sample containing 4% (w/v) sodium chloride. In this process, triazines in the water sample are extracted into the fine droplets of chlorobenzene. After centrifuging for 5 min at 6000 rpm, the fine droplets of chlorobenzene are sedimented in the bottom of the conical test tube (8.0+/-0.3 microL). The settled phase (2.0 microL) is collected and injected into the GC-MS for separation and determination of triazines. Some important parameters, viz, type of extraction solvent, identity and volume of disperser solvent, extraction time, and salt effect, which affect on DLLME were studied. Under optimum conditions the enrichment factors and extraction recoveries were high and ranged between 151-722 and 24.2-115.6%, respectively. The linear range was wide (0.2-200 microg L(-1)) and the limits of detection were between 0.021 and 0.12 microg L(-1) for most of the analytes. The relative standard deviations (RSDs) for 5.00 microg L(-1) of triazines in water were in the range of 1.36-8.67%. The performance of the method was checked by analysis of river and tap water samples, and the relative recoveries of triazines from river and tap water at a spiking level of 5.0 microg L(-1) were 85.2-114.5% and 87.8-119.4%, respectively. This method was also compared with solid-phase microextraction (SPME) and hollow fiber protected liquid-phase microextraction (HFP-LPME) methods. DLLME is a very simple and rapid method, requiring less than 3 min. It also has high enrichment factors and recoveries for the extraction of triazines from water.     

Analysis of furan in foods by headspace solid-phase microextraction-gas chromatography-ion trap mass spectrometry

A headspace-solid-phase microextraction (HS-SPME) coupled to gas chromatography-ion trap mass spectrometry (GC-IT-MS) method is proposed for the analysis of furan in different heat-treated carbohydrate-rich food samples. The extraction efficiency of six commercially available fibres was evaluated and it was found that a 75mum carboxen/polydimethylsiloxane coating was the most suitable for the extraction of the furan. Parameters affecting the efficiency of HS-SPME procedure such as extraction temperature and time, ionic strength, headspace and aqueous volume ratio (V(h)/V(w)), desorption temperature and time, were optimized. Quality parameters were established using spiked water and food samples. Linearity ranged between 0.02 and 0.5ngg(-1) and run-to-run and day-to-day precisions for food samples were lower than 6% and 10%, respectively. The limit of detection (LOD) of the method is sample dependent and ranged from 8 to 70pgg(-1), while the limit of quantification is from 30 to 250pgg(-1). Isotope dilution using furan-d(4) is proposed for furan determination providing similar results to those obtained by standard addition with internal standard (US Food and Drug Administration method). The developed HS-SPME-GC-IT-MS method was applied to the analysis of furan in different Spanish food samples from a local market, and concentrations ranging from 0.17 to 2279ngg(-1) were found.