Application of liquid chromatography-electrospray-tandem mass spectrometry for the identification and characterisation of linear alkylbenzene sulfonates and sulfophenyl carboxylates in sludge-amended soils

A novel procedure was developed for the simultaneous determination of linear alkylbenzene sulfonates (LAS) and their major metabolites, sulfophenyl carboxylates (SPC), in sludge-amended soil. After pressurised liquid extraction with methanol/water (90:10) and a clean-up on C18 solid-phase extraction cartridges, final analysis was done by ion-pair liquid chromatography-electrospray-tandem mass spectrometry (LC-ESI-MS/MS). With this method, SPC with 5-13 carbon atoms in the aliphatic side chain were identified for the first time in agricultural soils treated with sewage sludge. Quantification of LAS and SPC in soil from 10 field sites, which differed in the history of sludge application, gave total concentrations of 120-2840 microg kg(-1) for LAS and of 4-220 microg kg(-1) for SPC. The data provided evidence for rapid biodegradation of LAS in the initial phase after sludge amendment with a transitory build-up of high concentrations of, mainly, short-chain SPC. Trace amounts of residual LAS and SPC were detected in soils having received the last sludge treatment 10 days to 4 years prior to sampling.     

Determination of linear alkylbenzene sulfonates and their polar carboxylic degradation products in sewage treatment plants by automated solid-phase extraction followed by capillary electrophoresis-mass spectrometry.

Linear alkylbenzene sulfonates (LAS) were determined by solid-phase extraction (SPE), followed by capillary electrophoresis and mass spectrometry detection (CE-MS). The linear range of the proposed method varied from 33 to 316 and from 215 to 2057 micrograms L-1, depending on the compound, with limits of detection ranging from 4.4 to 23 micrograms L-1 when 200 ml of wastewater were preconcentrated. The analysis and confirmation of the polar carboxylic metabolites of LAS, the sulfophenyl carboxylic acids (SPC) was also achieved, and their presence was detected in both, influent and effluents of the sewage treatment plant (STP). [M - H]- ions were used for CE-MS confirmation and quantification. CE-MS diagnostic ions were the same ones used in LC-electrospray (ESI)-MS and corresponded to m/z 297, 311, 325 and 339 for C10LAS, C11LAS, C12LAS and C13LAS, respectively. For SPC identification, diagnostic ions corresponded to m/z 215 to 369 (with 14 mass unit steps) for C2 to C13SPC, respectively. LAS were determined in wastewater samples of the influent and effluent of three sewage treatment plants (STP), two of them using biological treatment with secondary settlement and receiving mainly domestic wastewater whereas one of the plants was operated with physiochemical treatment and received mainly industrial wastewater. The concentration levels of total LAS varied from 1000 to 1900 micrograms L-1 in the influents of STP, whereas in the effluents the concentrations varied from 125 to 360 micrograms L-1.     

Handling of marine and estuarine samples for the determination of linear alkylbenzene sulfonates and sulfophenylcarboxylic acids

Due to the physicochemical properties of linear alkylbenzene sulfonates (LAS), an anionic surfactant, it is difficult to obtain representative samples from sampling sites. Further, the high biodegradability of these compounds makes it necessary to study their biodegradation intermediates, sulfophenylcarboxylic acids (SPC) that do not have a surfactant character and show a different behavior. A procedure for determining and quantifying LAS and SPC in different environmental matrices by Soxhlet and solid-phase extractions and high-performance liquid chromatography is presented. The recoveries varied in the range from 85 to 102% for the water samples, and from 75 to 105% for sediment samples, with a standard deviation of between 1 and 7, and 2 and 11, respectively. Detection limits obtained were in the range from 5 to 10 microg kg(-1) for sediment samples (10 g) and from 0.2 to 0.4 microg l(-1) for water samples (250 ml). The method was applied to the simultaneous determination of LAS (C10-C13) and SPC (C4-C13) homologues in water, sediment and interstitial water collected from different areas of Spain.     

Determination of sulfophenylcarboxylic acids in marine samples by solid-phase extraction then high-performance liquid chromatography

An analytical method is presented for the determination of sulfophenylcarboxylic acids (SPC) produced by the biodegradation of linear alkylbenzene sulfonates (LAS) in marine samples. Isolation and concentration of the compounds was by solid-phase extraction. The different factors affecting extraction efficiency packing composition, pH, clean-up, ionic strength, and elution solvents--were studied and optimized. With the proposed method C4-C13SPC and C10-C13 LAS recoveries varied between 65% and 105%, with standard deviations between 0.1 and 5, respectively, for 100-mL samples and 100 microg L(-1) concentrations of each homolog. Detection limits within the range 0.5 g L(-1) (for C4SPC) to 1.0 g L(-1) (for C12SPC) were obtained by liquid chromatography with fluorescence detection. This method is the first to be proposed that enables the simultaneous determination of monocarboxylic SPC (C>3) and LAS homologs in marine samples by a simple, sensitive, and specific method giving high recoveries and reproducibility. SPC with from three to twelve carbon atoms in the carboxyl chain have been found in marine water samples.     

Characterization and determination of linear alkylbenzenesulfonates in environmental water samples by high-performance liquid chromatography with a hydrophilic polymer column and electrospray ionization mass spectrometric detection.

A liquid chromatography-mass spectrometry (LC/MS) method was developed for the separation and determination of linear alkylbenzenesulfonates (C10-C14 LAS) in environmental water samples using a hydrophilic polymer column (Shodex Mspak GF-310 4D). This method involves a solid-phase extraction of the LAS samples with a Sep-Pak PS-2 cartridge. The LAS components were separated on the column with a mobile phase of 29% (w/v) acetonitrile-water containing 0.8 mM di-n-butylammonium acetate and 0.2 M acetic acid, and were detected by mass spectrometry with electrospray ionization. Detection limits of the developed method based on selected ion monitoring (SIM) technique for the C10-C14 LAS standards were 13-47 ng L(-1). The concentrations of the C10-C14 LAS in the environmental water samples ranged between 5-317 microg L(-1) for a river water sample and 0.4-6.4 microg L(-1) for a seawater sample. Linear relationships between the logarithms of retention factors and the alkyl chain lengths for each phenyl positional isomer of LAS could successfully be used for the identification of the isomer peaks.     

Determination of bisphenol A in sewage effluent and sludge by solid-phase and supercritical fluid extraction and gas chromatography/mass spectrometry

Methods have been developed for the determination of bisphenol A (BPA) residues in municipal sewage and sludge samples. BPA in wastewater samples was enriched with a C18 solid-phase extraction cartridge, eluted with acetone, and converted to the pentafluoropropionyl derivative. For sludge samples, BPA was acetylated and extracted with supercritical carbon dioxide. In both cases, BPA-d16 was used as a surrogate to monitor extraction efficiency. Final analyses of derivatized sample extracts were performed by gas chromatography/mass spectrometry operating in the electron impact mode. For water samples, mean recoveries and standard deviations were 89 +/- 6, 94 +/- 4, and 85 +/- 7% at fortification levels of 1, 0.1, and 0.025 microg/L, respectively, with a method detection limit of 0.006 microg/L. For solid waste samples, mean recoveries and standard deviations were 93 +/- 5 and 92 +/- 6% at fortification levels of 2.5 and 0.25 microg/g, respectively, and the method detection limit was 0.05 microg/g. For the Canadian samples under investigation, concentrations of BPA ranged from 49.9 to 0.031 microg/L in sewage influent and effluent, and from 36.7 to 0.104 microg/g in sludge.     

Testing organic solvents for the extraction from fish of sulfophenylcarboxylic acids, prior to determination by liquid chromatography-mass spectrometry

The present paper describes the use of different solvent mixtures to extract from fish various sulfophenylcarboxylic acids (SPCs of C₆ to C₁₃), and their originating compounds, linear alkylbenzene sulfonates (LAS of C₁₀ to C₁₃). The analytical method utilized involves pressurized liquid extraction, followed by preconcentration of the samples, purification by solid-phase extraction, and finally identification and quantification of the target compounds by high-performance liquid chromatography-mass spectrometry using a system equipped with an electrospray interface operating in negative ion mode. The SPCs and LAS were extracted from spiked fish first with hexane to remove interference from fats, then with different mixtures of solvents: dichloromethane followed by methanol; 50:50 dichloromethane-methanol; and 30:70 dichloromethane-methanol. The LAS recoveries obtained with these three extraction options were high (between 68.5 and 80.8%); however, owing to the low percentages obtained for SPC homologues (13.5, 13.1, and 15.9%, respectively), another extraction procedure with methanol was developed in order to increase these recoveries. The percentage of recovery for total SPCs with the methanolic extraction was higher (90.1%), with a standard deviation of 9.9, and the LAS recoveries also increased (99.9%). Detection limits were between 1 and 22 ng g^?1 for LAS, and between 1 and 58 ng g^?1 for SPCs. Quantitation limits were between 4 and 73 ng g^?1 for LAS, and between 2 and 193 ng g^?1 for SPCs. This method has been applied to measure the biotransformation of 2ØC₁₀ LAS (where Ø is a sulfophenyl group) in fish exposed in a flow-through system, and enabled the separation and identification of SPCs from 5ØC₆ to 9ØC₁₀.     

Use of solid-phase extraction, reverse osmosis and vacuum distillation for recovery of aromatic sulfonic acids from aquatic environment followed by their determination using liquid chromatography-electrospray ionization tandem mass spectrometry

Three different sample preparation techniques (i) solid-phase extraction, (ii) reverse osmosis and (iii) vacuum distillation have been investigated and the recoveries were compared for determination of highly water-soluble benzene and stilbene sulfonic acids in aqueous environment by liquid chromatography with photodiode array (PDA) and electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). The recoveries were quite high using vacuum distillation (>90%) compared to solid phase extraction and reverse osmosis. The negative ion ESI mass spectra containing the peaks of quasimolecular ion [M-H]- allow the molecular mass determination of unknown compounds whereas the structures were proposed using fragments obtained from MS/MS analysis of [M-H]- ions. At lower fragmentation voltages only the quasimolecular ion [M-H]- was observed and as fragmentation voltages increased, it led to the formation of fragment ions corresponding to [M-H-SO3]-, [M-H-SO2]-, and SO3-. The detection limits were 1-28 microg/L with LC-ESI-MS. The sample collected from wastewater treatment plant was found to contain 21.1, 13.3, 12.1, 41.8 and 9.9 microg/L of cis-4,4(l)-diaminostilbene-2,2(l)-disulfonic acid (cis-DASDA), trans-4,4(l)-diaminostilbene-2,2(l)-disulfonic acid (trans-DASDA), 3-amino acetanilide-4-sulfonic acid (3-AASA), 4-chloroaniline-2-sulfonic acid (4-CASA), 2-chloroaniline-5-sulfonic acid (2-CASA), respectively.     

Application of probe sonication extraction for the determination of linear alkylbenzene sulfonates from sewage sludge. Comparison with other extraction methods

A new method based on probe sonication extraction (USP) prior to high performance liquid chromatography (HPLC) has been developed for the determination of linear alkylbenzene sulfonates (LAS) from sewage sludge. The optimized method was designed to be cost effective compared to existing extraction methods (ultrasonic assisted extraction, Soxhlet or pressurized liquid extraction) which may require large quantities of organic solvents, or costly instrumentation or equipment.The main factors affecting the extraction efficiency (extractant volume, ultrasounds power and extraction time) were optimized using compost sludge. The detection limit of total LAS in the sludge was 10 mg kg^− 1. The extraction of C₁₀-C₁₃ homologues is carried out using an extraction time of 7 min with 10 mL of methanol. Liquid chromatography with fluorescence (FL) detector is used for determination of LAS homologues. A mobile phase acetonitrile-water containing 0.1 M NaClO₄ (65:35) and isocratic elution was used. Compounds were eluted over 6 min at a flow rate of 1 mL/min. Polar interferences are eluted between 0 and 2 min and no purification of the samples is required prior to the final determination by high performance liquid chromatography (HPLC). The recoveries of LAS in spiked sewage sludge were between 84.0% and 97.0%, which reflect the efficiency of the method for extraction of these analytes from sewage sludge. Concentration levels found were between 11,858 mg kg^− 1 for digested sludge and 2379 mg kg^− 1 for compost sludge.     

Extraction and determination of sulfonamides, macrolides, and trimethoprim in sewage sludge

Pressurized liquid extraction (PLE) was optimized and validated for the determination of sulfonamide and macrolide antimicrobials and trimethoprim in sewage sludge samples. A mixture of water/methanol (50:50, v/v) was found as the most efficient extraction solvent. A temperature of 100 degrees C and a pressure of 100 bar were chosen for extraction. Two cycles of 5 min each efficiently extracted at least 97% of the total extractable amount of all studied analytes from activated sludge. The limits of quantification (S/N= 10) varied between 3 and 41 microg/kg dry weight (dw) and the relative recoveries ranged between 78 and 142%. Additionally, the influence of pH and different LC/MS/MS systems on the absolute recoveries was assessed. Of the investigated antimicrobials sulfapyridin, sulfamethoxazole, trimethoprim, azithromycin, clarithromycin and roxithromycin were detected in municipal sewage sludge samples. Concentrations in activated sludge ranged up to 197 microg/kgdw. In comparison, results obtained by ultrasonic solvent extraction were significantly lower for sulfonamides and in tendency lower for macrolides.     

Application of ion-exchange cartridge clean-up in food analysis. VI. Determination of six penicillins in bovine tissues by liquid chromatography-electrospray ionization tandem mass spectrometry

A multiresidue analytical method was developed for the quantification of benzylpenicillin (PCG), phenoxymethylpenicillin (PCV), oxacillin (MPIPC), cloxacillin (MCIPC), nafcillin (NFPC) and dicloxacillin (MDIPC) in bovine tissues using liquid chromatography- electrospray ionization tandem mass spectrometry (LC-ESI MS/MS) with a multiple reaction monitoring technique. Using the deuterated PCG and NFPC as internal standard was effective for improvement of repeatability and accuracy. We chose [M-H-141]- as a monitor ion of MRM analysis and [M-H]- as a precursor ion for each penicillin. Combination of an ion-exchange cartridge clean-up and ion-pair LC enable us to determine the residual penicillins using the standard curves made from standard solutions without the influence of sample matrix on the MS. The average recoveries of PCG, PCV, MPIPC, MCIPC, NFPC and MDIPC from bovine liver, kidney and muscle at the same concentrations as the tolerance levels of PCG (50 microg/kg) ranged from 77 to 101% with the coefficients of variation ranging from 0.7 to 4.2% (n = 5). The limits of quantification for the six penicillins were 2-10 microg/kg in bovine muscle, liver and kidney (S/N ratio >10).     

高效液相色谱-质谱法测定比格犬血浆中的艾普拉唑及其药代动力学

运用高效液相色谱-电喷雾质谱(HPLC-ESI-MS)技术,建立了快速、简单、灵敏的比格犬静脉滴注艾普拉唑钠盐后血药浓度的检测方法。血浆样品采用蛋白沉淀法,以丁螺环酮作为内标,色谱柱为Teknokroma Kromasil C18(100 mm×2.1 mm, 5 μm),流动相为水-甲醇-乙腈(69:8:23, v/v/v)(含0.1%的甲酸),流速0.2 mL/min,采用电喷雾(ESI)离子源以正离子方式检测。绘制血药浓度-时间曲线,并采用DAS 2.0计算药代动力学参数。方法学实验结果表明内源性杂质不干扰艾普拉唑和内标的测定,线性范围为5～10000 μg/L (r=0.994),最低定量限为5 μg/L,精密度和准确度均符合生物样品测定的要求。低、中、高3个浓度的绝对回收率在106%左右,基质效应小于142.0%,表明该方法适合比格犬血浆中艾普拉唑浓度的测定及药代动力学研究。比格犬静脉滴注艾普拉唑钠盐3个剂量(0.2 mg/kg、0.8 mg/kg和3.2 mg/kg)后的药-时曲线下面积(AUC(0~∞))分别为(2.4×104±3×103)、(8.8×104±1.6×104)和(5.4×105±8×104) μg/L•min,呈线性药物代谢动力学过程。     

Comparison of methods for extraction of ethyl carbamate from alcoholic beverages in gas chromatography/mass spectrometry analysis

A procedure to analyze ethyl carbamate (EC) by gas chromatography/mass spectrometry was optimized and validated. Deuterated EC (d5-EC) was added to the samples as an internal standard followed by extraction with polystyrene crosslinked polystyrene cartridges using minimal volumes of ethyl acetate. The EC response was measured in selective ion monitoring (SIM) mode and found to be linear in the range between the limit of quantitation (10 micro/L) and 1000 microg/L. EC recoveries varied from 92 to 112%, with the average value of 100 +/- 8%. The procedure compared well (r2 = 0.9970) with the existing AOAC Official Method with the added benefits of minimal solvent usage and reduced matrix interferences.     

Detection and identification of sulphonamide drugs in municipal waste water by liquid chromatography coupled with electrospray ionisation tandem mass spectrometry.

High-performance liquid chromatography coupled with positive-ion electrospray ionisation tandem mass spectrometry was used for the determination and confirmation of 13 sulphonamide drugs in environmental water samples in the low ng/L-range. Enrichment with concentration factors of 130-670 was performed by solid phase extraction, achieving recoveries of 50 to 90%. After gradient elution HPLC, detection and quantification was performed using selected reaction monitoring (SRM) with limits of detection between 0.2 and 3.7 microg/L. Confirmation was obtained by either SRM transitions of collision induced dissociation reactions or daughter ion mass spectra. Primary and secondary effluents of municipal waste water treatment plants and different surface waters were examined. The compounds sulphamethoxazole and sulphadiazine were detected and confirmed with concentrations ranging between 30-2000 ng/L and 10-100 ng/L, respectively. The compound sulphamethizole was detected in low amounts but could not be positively confirmed.     

GC-MS analysis of organic compounds in wastewater and sewage sludge

A multimethod based on liquid-liquid extraction and solid-liquid extraction for the analysis of persistent organic pollutants in water and sludge from sewage treatment plants has been established. Traces of 22 organic compounds used in industry and personal care products (PCPs) were analyzed by GC/MS. The LODs for the analytes were less than 2.3 ng/L for wastewater and 31 microg/kg (dry weight matter) for sewage sludge. Satisfactory recoveries (70-130%) were achieved. The validated method permits the analysis of water and sludge samples at various stages of the treatment from different sewage treatment plants. Thus, the distribution between water and sludge as well as the dissipation of the compounds analyzed were balanced. By this means, the efficiency of different wastewater treatment plants (WWTPs) can be evaluated and measures can be taken to optimize the treatment process at different stages.     

New rapid methods for determination of total LAS in sewage sludge by high performance liquid chromatography (HPLC) and capillary electrophoresis (CE)

Linear alkylbenzene sulfonates (LAS) are the most common synthetic anionic surfactant used in domestic and industrial detergents, with a global production of 2.4 × 10⁶ t year⁻¹. After use and disposal, LAS may enter the environment by one of the several routes, including by direct discharge to surface water or discharge to water from sewage treatment plants. Sewage treatment plants break down LAS only partly: some of them remain in effluent and other fraction is adsorbed in sewage solid.New and rapid methods for determination of total LAS from sewage sludge based on microwave assisted extraction and HPLC-FL and CE-DAD determination are proposed. The extraction of total LAS is carried out by using microwaves energy, an extraction time of 10 min and 5 mL of methanol. For HPLC-FL determination, mobile phase acetonitrile-water was used, comprising 60% (v/v) from 0 to 1 min and a flow rate of 1 mL min⁻¹ programmed to 100% acetonitrile between 1 and 2 min and a flow rate of 2 mL min⁻¹. The final composition was maintained for a further 5 min. The determination of total LAS by CE-DAD was performed in a phosphate buffer (10 mM, pH 9). The separation voltage was 25 kV and the temperature of the capillary was 30 °C. Injections were performed in the pressure mode and the injection time was set at 12 s. The determination of total LAS is carried out in less than 5 min. The methods did not require clean-up or preconcentration steps. Detection limit for total LAS in the sludge was 3.03 mg kg⁻¹ using HPLC-FL and 21.0 mg kg⁻¹ using CE-DAD, and recoveries were >85% using both determination methods. Concentrations of total LAS obtained using both methods were compared with the sum of concentrations of homologues LAS C-10, LAS C-11, LAS C-12 and LAS C-13 obtained using microwaves assisted extraction and HPLC-FL and CE-DAD determination.     

A new method for the routine analysis of LAS and PAH in sewage sludge by simultaneous sonication-assisted extraction prior to liquid chromatographic determination

Linear alkylbenzene sulphonates (LAS) and polycyclic aromatics hydrocarbons (PAH) are organic pollutants in sewage sludge which will have to be monitored in the European Union according to the third draft of a future sludge directive. In the present work, an analytical method for the simultaneous extraction of 4 LAS homologues and 16 PAH congeners in sludge from wastewater treatment plants is proposed to improve the routine analysis of these compounds in sludge samples. The method involves sonication assisted extraction, clean-up and preconcentration by solid phase extraction, and determination by high-performance liquid chromatography with ultraviolet diode array (UV-DAD) and fluorescence (FLD) detectors. Average recoveries were 87% for LAS and 76% for PAH, with relative standard deviations below 13%. Limits of quantification of LAS and PAH were in the range from 13 to 56 mg kg⁻¹ and from 80 to 650 μg kg⁻¹, respectively, when using UV-DAD. Limits of quantification of LAS and PAH were in the range 5-18 mg kg⁻¹ and from 1 to 150 μg kg⁻¹, respectively, when using FLD. The applicability of the proposed method was evaluated by the determination of these compounds in sludge from wastewater treatment plants in Seville (South Spain).     

Development and validation of a method for the confirmation of nicarbazin in chicken liver and eggs using LC-electrospray MS-MS according to the revised EU criteria for veterinary drug residue analysis.

A method is described for the quantitative confirmation of 4,4'-dinitrocarbanilide (DNC), the marker residue for nicarbazin in chicken liver and eggs. The method is based on LC coupled to negative ion electrospray MS-MS of tissue extracts prepared by liquid-liquid extraction. The [M-H]- ion at m/z 301 is monitored along with two transition ions at m/z 137 and 107 for DNC and the [M-H]- ion at m/z 309 for the internal standard, d8-DNC. The method has been validated according to the new EU criteria for the analysis of veterinary drug residues at 100, 200 and 300 microg kg(-1) in liver and at 10, 30 and 100 microg kg(-1) in eggs. Difficulties concerning the application of the new analytical limits, namely the decision limit (CCalpha) and the detection capability (CCbeta) to the determination of DNC in both liver and eggs are discussed.     

三甲基硅烷衍生化-气相/质谱联用法分析尿中7-氨基硝西泮

 建立了分析尿中硝西泮主要代谢物 7 氨基硝西泮 (7 ANIZ)的三甲基硅烷衍生化 气相 /质谱联用方法。尿样经乙醚 乙酸乙酯 (体积比为 99∶1 )萃取后 ,用N ,O 双 (三甲基硅 )三氟乙酰胺进行衍生化 ,检测衍生物的总离子流。根据 7 ANIZ衍生物质谱中主要特征离子的相对丰度及其质量的保留时间进行定性分析 ;用 7 氨基氯硝西泮做内标 ,根据衍生物基峰离子的质量进行定量分析。本方法中 7 ANIZ的萃取率为 82 8% ,线性范围为 1 0 μg/L～ 50 0 μg/L,检出限为 1 2 μg/L,定量限为 3 5μg/L。     

Multiresidue analysis of fungicides in soil by sonication-assisted extraction in small columns and gas chromatography

A rapid multiresidue method for the simultaneous determination of 14 fungicides in soil was developed. Fungicides were exacted from soil, placed in small columns, by sonication-assisted extraction with ethyl acetate. The effect of residue residence time and soil moisture content on the fungicide recovery was studied. Residue levels in soil were determined by gas chromatography with electron-capture and nitrogen-phosphorus detection. Residue identities were confirmed by gas chromatography coupled with mass spectrometry, in the selected ion monitoring mode. Recovery studies were carried out at 0.5, 0.1 and 0.05 microg/g fortification levels for each fungicide, and average recoveries obtained for these compounds ranged from 80 to 104% with relative standard deviations between 1 and 8%. The method is linear over the range assayed, 0.5-0.05 microg/g, and the detection limit for the fungicides studied varied from 2 to 10 microg/kg.