Automated Online Solid-phase Extraction Research Articles

A Novel and Fast Online-SPE-LC-MS/MS Method to Quantify Thyroid Hormone Metabolites in Rat Plasma.

Since the focus in regulatory toxicology has drifted toward the identification of endocrine disruptors, the improvement in determination of alterations in the thyroid hormone system has become more important. THs are involved in several molecular processes important for a proper pre- and postnatal development so that disturbances can inter alia lead to incorrect brain maturation and/or disturbed metabolic processes (thermogenesis or lipolysis). In this publication, a new automated online solid-phase extraction (SPE)-liquid chromatography (LC)-tandem mass spectrometry (MS/MS, xLC-MS/MS) is introduced which simultaneously analyzes total T4, T3, rT3, T2, and T1. Method validation parameters are presented, and the method was positively verified by analyzing control and PTU-treated rat plasma samples (time points day 7, 14, and 28) for their total TH content. The obtained results were compared to published results by using a radioimmunoassay method. The automated SPE system ensures a consistent unified sample preparation, and this method overall showed sufficient specificity and accuracy to detect the given analytes in rat plasma. For the preparation of 50 μL of rat plasma, the following LOQs were established: 0.020 nM for T1, 0.029 nM for T2, 0.023 nM for rT3 and T3, and 3.22 nM for T4. This method is suitable to assess the identification of mechanisms leading to adverse effects, such as disturbed TH metabolism and regulation.

Determination of Vancomycin and Norvancomycin Residues in Milk by Automated Online Solid-Phase Extraction Combined With Liquid Chromatography-High Resolution Mass Spectrometry.

Vancomycin and norvancomycin, as potent antibacterial retention drugs, were used illegally on animals bred for food, which directly affected the quality and safety of animal-derived food, and even harmed human health. A fast analysis method, which was adopted to detect residues of vancomycin and norvancomycin in milk, was implemented on a chromatographic system containing online solid-phase extraction (SPE) device that combined with high-resolution mass spectrometer (HRMS). First, the analytes were added to the blank milk sample were extracted with water [containing 0.1% trifluoroacetic acid (TFA)]-acetonitrile (ACN) (8:2, v/v), and then were purified and enriched on a C18-XL column, whereafter eluted from the purification column onto the analytical column (Shiseido Capcell Pak ADME column) for chromatographic separation prior to hybrid quadrupole-Orbitrap (Q-Orbitrap) detection. The results showed that the limit of detection (LOD) for each analyte and the limit of quantitation (LOQ) were 0.15 and 0.5 μg/kg, respectively. The correlation coefficient(s) of vancomycin and norvancomycin ranged from 0 to 200 ng/mL were greater than 0.9983. These validations reflected that it was suitable for the established method to rapidly analyze vancomycin and norvancomycin residues in milk. The method for detecting vancomycin and norvancomycin residues in milk by online SPE combined with LC-HRMS. Online SPE technology realized automation, and the application of HRMS greatly improved the reliability of qualitative and quantitative analyses. The developed method is fast, simple, and reliable; each methodological index can meet requirements of trace analyses of vancomycin and norvancomycin in milk.

Targeted profiling of 24 sulfated and non-sulfated bile acids in urine using two-dimensional isotope dilution UHPLC-MS/MS.

Bile acids serve as biomarkers for liver function and are indicators for cholestatic and hepatobiliary diseases like hepatitis, cirrhosis, and intrahepatic cholestasis of pregnancy (ICP). Sulfation and renal excretion of bile acids are important elimination steps. The power of ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) allows specific profiling of primary and secondary bile acids as well as their sulfated counterparts. Twenty-four sulfated and non-sulfated primary and secondary bile acids were quantified in urine with 15 corresponding stable isotope labeled internal standards by using two-dimensional UHPLC-MS/MS. The sample preparation was based on a simple dilution with a methanolic zinc sulfate solution followed by an automated online solid phase extraction clean up. The validation results of the method fulfilled the criteria of the European Medicine Agency (EMA) "Guideline on bioanalytical method validation". To verify fitness for purpose, 40 urine samples were analyzed which showed an average of 86% sulfation, 9.1% taurine-conjugation, 14% non-conjugation, and 77% glycine-conjugation rates. Lossless one-pot sample preparation, automated sample purification, and high number of internal standards are major innovations of the presented profiling method, which may allow diagnostic application of BA profiling in the future.

Development of a high-throughput multi-residue method for analysis of common pesticides in aquatic environments by automated online solid phase extraction coupled with LC-MS/MS

A reliable method based on fully automated online solid phase extraction coupled with LC-MS/MS was developed for the high throughput analysis of 111 common pesticides or metabolites in three aquatic matrices.

Determination of Deoxynivalenol and Its Derivative in Corn Flour and Wheat Flour Using Automated On-line Solid-Phase Extraction Combined with LC-MS/MS.

An automated on-line solid-phase extraction (SPE) combined with LC-MS/MS method was developed for determination of deoxynivalenol (DON), 3-acetyl-DON and 15-acetyl-DON in corn flour and wheat flour samples. The extraction solvent of the samples was injected into the automated on-line SPE system to remove matrix interference. After washing step, the targets were eluted from the SPE cartridge into liquid chromatography (LC) column. Several SPE parameters including injection volume, elution volume and eluting flow rate were assessed and optimized. Method validation was evaluated and good linearity was obtained (R2 > 99%) with the limit of detection of 0.1-0.2μg/kg. Recoveries were evaluated in spiked corn flour and wheat flour samples at three concentrations and the values ranged from 86.5% to 99.7%. The benefit of the present method with automated on-line SPE system is the ability to inject directly pure extracts into LC-MS/MS, offering faster analyses and improving analysis efficiency.

Simultaneous Determination of Five Hormones in Milk by Automated Online Solid-Phase Extraction Coupled to High-Performance Liquid Chromatography.

Many hormones show the effects of protein assimilation and growth promotion, and they are frequently used as veterinary drugs in livestock, which has harmful effects on human health. It is necessary to determine their contamination level in animal-derived food, especially in milk. In this study, a detailed procedure is described for an automated online solid-phase extraction (SPE)-HPLC method capable of detecting five hormones (i.e., estriol, prednisone acetate, hydrocortisone, diethylstilbestrol, and estrone) in cow milk. The corresponding milk samples were precipitated by addition of acetonitrile and then purified as well as enriched by a polar-enhanced polymer (PEP) online SPE column. The supernatants were directly injected into the online SPE-HPLC system using methanol-water as the mobile phase mixture. The linearity range of the method was 0.1-25 μg/mL for prednisone acetate, hydrocortisone, and diethylstilbestrol, 0.2-25 μg/mL for estriol, and 0.5-25 μg/mL for estrone, with correlation coefficients (r) ranging from 0.9994 to 0.9996. The recovery rates determined at three concentration levels for the five compounds were in the range of 70.82-112.90%. LODs of estriol, prednisone acetate, hydrocortisone, diethylstilbestrol, and estrone were 0.023, 0.005, 0.006, 0.004, and 0.054 μg/mL, respectively. This automated online SPE-HPLC method was both effective and reliable in the simultaneous measurement of five hormones, and the method was successfully applied to the detection of five hormone species in milk. An automated online SPE-HPLC method has been developed for the analysis of five hormones in cow milk. Online SPE proved to be a powerful technique for determining five hormones simultaneously. This method ensured simple sample pretreatment and less operation time. The established method was successfully applied to the analysis of five hormone species in milk.

High-throughput screening for target compounds in smokeless powders using online-SPE tandem mass spectrometry

ABSTRACT The detection and quantification of compounds present in smokeless powders plays an important role in various fields such as environmental and forensic science. Often, time and labour consuming sample preparation techniques such as solid phase extraction (SPE) are required to facilitate either pre-concentration or sample clean-up with complex matrices. This paper describes the first application of the completely automated online SPE system RapidFire® connected to a triple quadrupole mass spectrometer for smokeless powder/gunshot residue analysis. The optimized method involved sample loading during 2000 ms using UP water (0.1% formic acid) at a flowrate of 1.25 mL/min on a Type C C18 cartridge followed by elution of the target compounds for 3000 ms using IPA (0.1% formic acid) at 0.75 mL/min. Target compounds were detected in soil (DPA, 2-NDPA, EC, NG, 2,4-DNT) and cotton swabs (NG) in only 8 seconds per sample with detection limits of 0.223 ppm (DPA), 0.104 ppm (2-NDPA), 0.0949 ppm (EC), 0.187 ppm (NG) and 0.128 ppm (2,4-DNT). The presented method showed promising results for the analysis of five target analytes in soil samples. Further optimisations can extend the analysis to other sample matrices and include more analytes potentially present in smokeless powders and GSR.

Automated online solid-phase extraction liquid chromatography tandem mass spectrometry investigation for simultaneous quantification of per- and polyfluoroalkyl substances, pharmaceuticals and personal care products, and organophosphorus flame retardants in environmental waters

This work describes development of a quick and accurate online solid-phase extraction (SPE) liquid chromatography tandem mass spectrometry method for simultaneous determination of 87 emerging organic compounds, including 22 per- and polyfluoroalkyl substances, 58 pharmaceuticals and personal care products, and 7 organophosphorus flame retardants, in diverse water matrices. Considering the wide range of physicochemical properties for the target contaminants, efficient analysis in one injection is challenging. Thus, key extraction and analytical parameters, including online SPE sorbent, mobile phase additives, sample pH, loading solvent pH and composition, injection volume, and valve-switching time, were systematically optimized. The final conditions, namely a polymeric reversed-phase column with alkaline samples and an acidic loading solvent, provided satisfactory results for all target analytes compared to conventional methods that employ acidic samples for multi-residue analysis. The method detection limits (MDLs) ranged from 0.16 to 5.13 ng L−1 with 85% of MDLs lower than 2 ng L−1 for sample volumes of just 1.8 mL. The method also demonstrated satisfactory accuracy with 82% of analytes exhibiting 70–130% recovery. Importantly, only 30 min was required per sample. The optimized method was successfully applied to investigate the removal efficiency of emerging contaminants in a drinking water treatment plant and to analyze the environmental occurrence of target analytes. The method is sensitive, reliable, labor-saving, and cost effective, and therefore has the potential to advance large-scale environmental monitoring programs.

Comparison of the Detection Windows of Heroin Metabolites in Human Urine Using Online SPE and LC-MS/MS: Importance of Morphine-3-Glucuronide.

Heroin abuse is a serious problem that endangers human health and affects social stability. Though often being used as confirmation of heroin use, 6-monoacetylmorphine (6-MAM) has limitations due to its short detection window. To compare the detection windows of heroin metabolites (morphine (MOR), 6-MAM, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G)) in human urine, an automated online solid phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and fully validated. The limits of detections (LODs) of the four metabolites were in the range of 1.25-5 ng/mL. Intra and inter-day precision for all the metabolites was 0.4-6.7% and 1.8-7.3%, respectively. Accuracy ranged from 92.9 to 101.7%. This method was then applied to the analysis of urine samples of 20 male heroin abusers. M3G was detected 9-11 days after admission to the drug rehabilitation institute in 40% of heroin users while MOR or M6G was not always detected. The detection window of M3G was thus the longest. Furthermore, M3G had a much higher concentration than MOR and M6G. Therefore, M3G could provide diagnostic information with regard to heroin exposure in the combination with other clues (e.g., heroin seizures at the scene).

A rapid and sensitive method for the control of selected regulated and emerging mycotoxins in beer

A fast method using automated online solid-phase extraction (SPE) coupled to liquid-chromatography/high resolution mass spectrometric (LC-HRMS) detection for the determination of 12 mycotoxins in beer was developed and fully validated according to the performance criteria set in the European Union (EU) guidelines. Mycotoxin detection was achieved by full-scan HRMS with electrospray ionisation in positive ion mode within 13 min. No significant matrix interferences were observed. The lowest limits of detection (LODs) were achieved for emerging mycotoxins (beauvericin and enniatins) and ochratoxin A at levels between 0.01 and 0.02 μg/l, while the overall LODs were in the range of 0.01-0.30 μg/l. The elaborated method showed good performance in the analysis of beer samples with good linearity (R2>0.999), intra-day and inter-day precision at the levels of <12% and <13%, respectively, and recoveries in the range of 80-119%. Finally, this fully automated, sensitive, and reliable online SPE-HPLC-HRMS method was successfully applied for the analysis of 25 Latvian beers and the obtained results were comparable or even better than those obtained using the well-established Quick, Easy, Cheap, Effective, Rugged, and Safe, the QuEChERS, methodology.

Multi-residue analysis of sulfonamide antibiotics in honey samples by on-line solid phase extraction using molecularly imprinted polymers coupled to liquid chromatography-tandem mass spectrometry

This work reports the development of a sensitive and automated online solid phase extraction method using molecularly imprinted polymers (MISPE) coupled to high performance liquid chromatography–tandem mass spectrometry (LC–MS/MS) (HPLC), for the identification and quantification of six sulfonamide antibiotics, namely sulfapiridyne, sulfadoxine, sulfaquinoxaline, sulfacetamide, sulfachloropyridazine and sulfamonomethoxine in honey samples from the Cuban market. The samples were hydrolyzed in acidic media to release the sugar-bound sulfonamides before injection into the preconcentration system. Polymer composition was selected using a combinatorial approach. Several parameters affecting the performance of the MISPE method were optimized to reduce nonspecific binding with the non-imprinted polymer and achieve a selective rebinding of the target antimicrobials. Method validation was performed according to Commission Decision 2002/657/EC in terms of linearity, recoveries, precision, specificity, decision limit (CCα) and detection capability (CCβ). Intraday recoveries at three concentration levels (1, 10 and 20 μg Kg-1) were between 84.3 and 104.7% (RSD < 11.6%) while interday average recoveries were in the ranges 65.5–119.3% (RSDs < 10.4%). The values of CCα and CCβ values were in the ranges 0.1–4.2 and 0.2–4.4 μg kg−1, respectively. The limits of detection and quantitation for the investigated sulfonamides ranged from 0.004–1.050 µg kg−1 and 0.014–3.499 µg kg−1, respectively. The method described has been applied to the analysis of honey samples from Cuban producers.

Measurement of apixaban, dabigatran, edoxaban and rivaroxaban in human plasma using automated online solid-phase extraction combined with ultra-performance liquid chromatography-tandem mass spectrometry and its comparison with coagulation assays

BackgroundMeasurement of direct oral anticoagulants (DOACs) concentration in patient blood is essential in special clinical circumstances. MethodsWe developed a fast, selective and sensitive method for simultaneous measurement of DOACs in human plasma consisting of an automated online solid-phase extraction method coupled with ultra-performance liquid chromatography electrospray ionization-tandem mass spectrometry (online SPE-UPLC-MS/MS). ResultsThe calibration curves of all DOACs were linear over the working range (apixaban: 0.25–760 μg/L, r > 0.99; dabigatran: 0.5–900 μg/L, r > 0.99; edoxaban: 0.6–800 μg/L, r > 0.99; rivaroxaban: 0.5–900 μg/L, r > 0.99). Limits of detection in the plasma matrix were < 0.2 μg/L, whereas the lower limits of quantification were < 0.6 μg/L for all DOACs. The intraassay and interassay CV for all DOACs were < 6%. Mean recoveries were between 61.4% and 91.6%. Method comparison between our online SPE-UPLC-MS/MS assay and commercially available functional based coagulation assays using patient samples showed a high degree of correlation for all investigated DOACs. ConclusionsWe developed and validated the first online SPE-UPLC-MS/MS method for fast, sensitive, specific, and reliable measurement of the new generation of DOACs and compared this method with commercial available coagulation assays.

Simultaneous determination of five azadirachtins in the seed and leaf extracts of Azadirachta indica by automated online solid-phase extraction coupled with LC\u2013Q-TOF\u2013MS

Neem (Azadirachta indica) extract is well-known as a natural pesticide for the control of agricultural pests. Azadirachtin A and its structural analogues are considered as active compounds. However, the amounts of azadirachtins varies in neem extracts, providing a variety of insecticidal activities. In this study, a novel method of automated online solid-phase extraction coupled with liquid chromatography/quadrupole-time-of-flight mass spectrometry (SPE-LC–Q-TOF–MS) was developed and validated for simultaneous quantification of five azadirachtins (azadirachtins A, B, D, H and I) in seed and leaf extracts of A. indica. Different experimental parameters (such as SPE cartridge, injection volume and washing step) were optimized. The optimized SPE-LC–Q-TOF–MS method showed good recovery (82.0–102.8%), linearity (r2 ≥ 0.9991) and precision (0.83–4.83%). The limit of detections (LODs) for the five analytes ranged from 0.34 to 0.76 ng mL−1. The validated method was successfully applied for determination of the analytes in the neem leaves and seeds from different locations and a neem formulation. The online SPE-LC–Q-TOF–MS method was found to be a simple, precise and accurate and can be used as a powerful tool for quality control of neem extracts or its formulations.

First UHPLC-MS/MS method coupled with automated online SPE for quantification both of tacrolimus and everolimus in peripheral blood mononuclear cells and its application on samples from co-treated pediatric patients.

Tacrolimus (TAC, FK-506) and everolimus (EVE, RAD001) are immunosuppressors used to treat pediatric patients undergoing liver transplantation. Their hematic TDM by liquid chromatography became standard practice. However, it does not always reflect concentrations at their active site. Our aim was to develop and validate a new method for the simultaneous TAC and EVE quantification into target cells: peripheral blood mononuclear cells (PBMCs). Peripheral blood mononuclear cells were collected using cell preparation tubes; cells number and mean cell volume were evaluated by an automatic cell counter. TAC and EVE were quantified using UHPLC-MS/MS coupled with an automated online solid-phase extraction platform. Chromatographic run was performed on an Acquity UPLC® BEH C18 1.7μm (2.1×50mm) column at 45°C, for 6min at 0.5ml/min. Mobile phases were water and methanol, both with 2mm ammonium acetate and 1ml/l formic acid). XBridge® C8 10μm (1×10mm) SPE cartridges were used, and the internal standard was ascomycin. Following Food and Drug Administration guidelines, method validation resulted in high sensitivity and specificity. Calibration curves were linear (r2 =0.998) and intra-day and inter-day imprecision and inaccuracy were <15%. A reproducible matrix effect was observed, with a good recovery for all compounds. Drug amounts in 15 'real' PBMCs samples from five pediatric patients in co-treatment resulted within the calibration range (0.039-5ng). Concentrations from each patient were standardized using their evaluated mean cell volume: intra-PBMCs concentration was meanly 19.23 and 218.61 times higher than the hematic one for TAC and EVE, respectively. This method might be useful in clinical routine, giving reliable data on drugs concentration at the active site. Copyright © 2017 John Wiley & Sons, Ltd.

Automated online solid-phase extraction-liquid chromatography mass spectrometric analysis of dithianon in water.

An automated online solid-phase extraction-liquid chromatography mass spectrometry (SPE-LC/MS) method was developed for the quantification of dithianon in surface water samples, using warfarin as internal standard. The method was developed on a liquid chromatography (LC) system with Flexible Cube interfaced to a quadrupole time-of-flight (Q-TOF) mass spectrometer. A small volume of acidified water (1 mL) was spiked with internal standard, pre-concentrated online on polymeric cartridges and analyzed by full-scan MS in high-resolution conditions. The quantitative data were obtained by [M]-• of dithianon and [M - H]- of warfarin, used as internal standard. The chromatographic separation was performed on a C18 column with a gradient mobile phase consisting of acetonitrile and water containing 0.05% acetic acid. The method was validated to measure concentrations of dithianon in the range of 0.010-4 µg L-1 in surface water samples. Twenty real water samples, collected from Torrente Novella, Val di Non (TN, Northern Italy), during fungicide treatments of large apple orchards, were analyzed. All samples were kept in glass bottles and stored in the lab at -20°C until analysis. It was found that in all samples dithianon was undetectable: if it is present, its concentration was lower than the limit of detection (LOD) (0.008 µg L-1.To investigate the stability of dithianon, a series of water samples were spiked at different concentrations and analyzed after different storage conditions. Results suggested that dithianon is not stable in water stored at -20°C at neutral or basic pH, but the addition of acetic acid to pH = 3.5 increases its stability to at least two weeks.

Online solid phase extraction with liquid chromatography–tandem mass spectrometry for determination of estrogens and glucocorticoids in water

The present work describes the development of a novel fully automated online solid phase extraction (SPE) coupled with high performance liquid chromatography-tandem mass spectrometry (LC–MS/MS) using negative electrospray ionisation (ESI) for the simultaneous determination of six estrogens and six glucocorticoids in water. Filtered water samples (5mL) were preconcentrated on a HyperSep™ Retain PEP SPE cartridge, eluted in back-flush mode, and separated on an LC column before analysis by tandem mass spectrometry. The total analysis time for each sample was 17min. Different experimental parameters such as the type of online SPE cartridge, loading flow rate, and composition of methanol in the loading phase were optimised. The intra-day repeatability of method ranged from 1.48 to 9.68% for all analytes, and the inter-day reproducibility ranged from 2.03 to 8.63% for all analytes, except for dexamethasone at 11.95%. These were calculated based on the peak area responses of the targeted analytes spiked at 50ng/L in ultrapure water. The method also showed good linearity from 1 to 100ng/L, with the limits of detection (LODs) ranging from 0.16 to 2.14ng/L. The proposed method was applied to the analysis of municipal wastewater. This fully automated online SPE extraction coupled with LC–MS/MS method is effective and reliable to measure estrogens and glucocorticoids simultaneously due to its high throughput, relatively low solvent consumption, reusability of the online SPE cartridge, and reduction of manual labor.

A direct assay for the routine measurement of testosterone, androstenedione, dihydrotestosterone and dehydroepiandrosterone by liquid chromatography tandem mass spectrometry.

The measurement of androgens in many laboratories is often limited to testosterone. To more accurately determine the androgen status in both sexes, the measurement of other androgens such as dihydrotestosterone, the more potent metabolite of testosterone, and androstenendione and dehydroepiandrosterone, the most abundant circulating androgens in women would be informative. We report a combined liquid chromatography tandem mass spectrometry method for the measurement of these androgens. Internal standards in methanol (10 µL) were added to 100 µL serum followed by the addition of zinc sulphate (100 µL). After mixing, 100 µL of acetonitrile was added and was further mixed. The samples were centrifuged and the steroids extracted using an automated online solid phase extraction on a C18 cartridge by a Waters Acquity with online sample manager coupled to a TQS mass spectrometer. Separation of the androgens was achieved by liquid chromatography. The run time was 6.5 min per sample. The lower limit of quantitation was 0.1 nmol/L for testosterone, androstenedione and dihydrotestosterone and 1 nmol/L for dehydroepiandrosterone. The coefficient of variation of the assay in serum for testosterone was <6%, androstenedione <8% and dihydrotestosterone and dehydroepiandrosterone <10%. We have developed a rapid assay for the liquid chromatography tandem mass spectrometry measurement of testosterone, androstenedione, dihydrotestosterone and dehydroepiandrosterone in a routine clinical laboratory. The assay requires a small volume of serum, and all analytes are measured simultaneously. The assay is rapid and simple to execute offering the potential for routine clinical application.

Online solid phase extraction liquid chromatography using bonded zwitterionic stationary phases and tandem mass spectrometry for rapid environmental trace analysis of highly polar hydrophilic compounds – Application for the antiviral drug Zanamivir

Zanamivir (Za) is a highly polar and hydrophilic antiviral drug used for the treatment of influenza A viruses. Za has been detected in rivers of Japan and it's environmental occurrence has the risk of inducing antiviral resistant avian influenza viruses. In this study, a rapid automated online solid phase extraction liquid chromatography method using bonded zwitterionic stationary phases and tandem mass spectrometry (SPE/LC–MS/MS) for trace analysis of Za was developed. Furthermore, an internal standard (IS) calibration method capable of quantifying Za in Milli-Q, surface water, sewage effluent and sewage influent was evaluated. Optimum pre-extraction sample composition was found to be 95/5 v/v acetonitrile/water sample and 1% formic acid. The developed method showed acceptable linearities (r2≥0.994), filtration recovery (≥91%), and intra-day precisions (RSD≤16%), and acceptable and environmentally relevant LOQs (≤20ngL−1). Storage tests showed no significant losses of Za during 20 days and +4/−20°C (≤12%) with the exception of influent samples, which should be kept at −20°C to avoid significant Za losses. The applicability of the method was demonstrated in a study on phototransformation of Za in unfiltered and filtered surface water during 28 days of artificial UV irradiation exposure. No significant (≤12%) phototransformation was found in surface water after 28 days suggesting a relatively high photostability of Za and that Za should be of environmental concern.

Rapid ultra-trace analysis of sucralose in multiple-origin aqueous samples by online solid-phase extraction coupled to high-resolution mass spectrometry.

Because of its widespread consumption and its persistence during wastewater treatment, the artificial sweetener sucralose has gained considerable interest as a proxy to detect wastewater intrusion into usable water resources. The molecular resilience of this compound dictates that coastal and oceanic waters are the final recipient of this compound with unknown effects on ecosystems. Furthermore, no suitable methodologies have been reported for routine, ultra-trace detection of sucralose in seawater as the sensitivity of traditional liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis is limited by a low yield of product ions upon collision-induced dissociation (CID). In this work, we report the development and field test of an alternative analysis tool for sucralose in environmental waters, with enough sensitivity for the proper quantitation and confirmation of this analyte in seawater. The methodology is based on automated online solid-phase extraction (SPE) and high-resolving-power orbitrap MS detection. Operating in full scan (no CID), detection of the unique isotopic pattern (100:96:31 for [M-H](-), [M-H+2](-), and [M-H+4](-), respectively) was used for ultra-trace quantitation and analyte identification. The method offers fast analysis (14 min per run) and low sample consumption (10 mL per sample) with method detection and confirmation limits (MDLs and MCLs) of 1.4 and 5.7 ng/L in seawater, respectively. The methodology involves low operating costs due to virtually no sample preparation steps or consumables. As an application example, samples were collected from 17 oceanic and estuarine sites in Broward County, FL, with varying salinity (6-40 PSU). Samples included the ocean outfall of the Southern Regional Wastewater Treatment Plant (WWTP) that serves Hollywood, FL. Sucralose was detected above MCL in 78% of the samples at concentrations ranging from 8 to 148 ng/L, with the exception of the WWTP ocean outfall (at pipe end, 28 m below the surface) where the measured concentration was 8418 ± 3813 ng/L. These results demonstrate the applicability of this monitoring tool for the trace-level detection of this wastewater marker in very dilute environmental waters.

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.