Automated Solid-phase Extraction Research Articles

Simultaneous determination of four trace estrogens in feces, leachate, tap and groundwater using solid-liquid extraction/auto solid-phase extraction and high-performance liquid chromatography with fluorescence detection.

A simple and selective high-performance liquid chromatography method coupled with fluorescence detection was developed for the simultaneous measurement of trace levels of four estrogens (estrone, estradiol, estriol and 17α-ethynyl estradiol) in environmental matrices. For feces samples, solid-liquid extraction was applied with a 1:1 v/v mixture of acetonitrile and ethyl acetate as the extraction solvent. For liquid samples (e.g., leachate and groundwater), hydrophobic/lipophilic balanced automated solid-phase extraction disks were selected due to their high recoveries compared to conventional C18 disks. Chromatographic separations were performed on a reversed-phase C18 column gradient-eluted with a 45:55 v/v mixture of acetonitrile and water. The detection limits were down to 1.1 × 10(-2) (estrone), 4.11 × 10(-4) (estradiol), 5.2 × 10(-3) (estriol) and 7.18 × 10(-3) μg/L (17α-ethynyl estradiol) at excitation/emission wavelengths of 288/310 nm, with recoveries in the range of 96.9 ± 3.2-105.4 ± 3.2% (n = 3). The method was successfully applied to determine estrogens in feces and water samples collected at livestock farms and a major river in Northeast China. We observed relatively high abundance and widespread distribution of all four estrogens in our sample collections, implying the urgency for a comprehensive and intricate investigation of estrogenic fate and contamination in our researched area.

Liquid chromatography with tandem mass spectrometry for the determination of flufenoxuron in blood using automatic solid phase extraction and its application to a fatal case of flufenoxuron poisoning

A liquid chromatography/tandem mass spectrometry method with solid phase extraction for the detection and the quantitation of flufenoxuron in an aliquot of blood was developed and validated. Flufenoxuron belongs to a benzoylurea insecticide and is the active ingredient of Cascade™. The analyte in postmortem specimens was extracted by solid-phase extraction with Bond Elut Certify cartridge. After the elution layer was evaporated, the residue was reconstituted with 70% methanol for LC/MS/MS analysis. Separations were carried out on a Synergi® 2.5u Fusion-RP 100 A column with column temperature kept at 40°C at a flow rate of 0.4mL/min. The mobile phase was composed of 5mM ammonium formate in 10% methanol and 5mM ammonium formate in 90% methanol using gradient elution. A triple quadruple mass spectrometer equipped with an electrospray ionization source operated in a positive ion mode with selective reaction monitoring mode. Atrazine-d5 was used as internal standard. The assay was linear over 0.02–1.0mg/L (r2=0.999). Limit of detection (LOD) and limit of quantitation (LOQ) in blood were 0.009mg/L (S/N=3) and 0.02mg/L (S/N=10), respectively. The accuracy and the precision were <14.9% of bias% and <8.1% of CV%, which are acceptable criteria according to toxicology laboratory guidelines. Relative recoveries with 0.02, 0.1 and 1.0mg/L (in blood) were 112.3%, 101.2% and 111.0% (n=5), respectively. The developed method was applied in forensic toxicology to determine flufenoxuron in postmortem specimens in a fatal case of flufenoxuron intoxication in a 48-year-old-man who was found dead on bed in a small room after vomiting on the floor. The postmortem heart blood, peripheral blood and gastric contents were analyzed for flufenoxuron with the result of 6.3mg/L in heart blood, 3.2mg/L in peripheral blood and 30.6mg/kg in gastric contents, respectively. The concentration ratio of the heart/peripheral blood of flufenoxuron was 2.0, and the ratio of gastric contents/peripheral blood was 9.4, suggesting possible postmortem redistribution and there may be a massive amount of flufenoxuron orally ingested. This case study is the first report of lethal concentrations of flufenoxuron in postmortem specimens.

Quantification of Drugs in Brain Samples.

Due to the lack of certified reference material, a reliable quantification in complex postmortem matrices can only be performed either by the addition of isotope-labelled standards or by the standard addition method. Although standard addition is a basic quantification procedure, its practical implementation is challenging, and a highly reproducible extraction method is essential. Therefore, an automated solid-phase extraction screening procedure was validated in respect to the specific requirements in postmortem analyses, using pig brain fortified with nine compounds to represent a realistic postmortem setting. The validation parameters linearity, repeatability, reproducibility and recovery were selected to test the method's 'fitness for purpose'. All obtained results were satisfying, although the method was not optimized for the selected compounds. Therefore, this validated method could be used for further standard addition experiments to evaluate the importance of the initial estimated concentration for the calculation of concentrations to set up the calibration curve. We could show that the best results were obtained when the estimated concentration was close to the real concentration. In case of a deviation, an underestimation is more favorable than an overestimation.

Automatic In-Syringe Dispersive Microsolid Phase Extraction Using Magnetic Metal-Organic Frameworks.

A novel automatic strategy for the use of micro- and nanomaterials as sorbents for dispersive microsolid phase extraction (D-μ-SPE) based on the lab-in-syringe concept is reported. Using the developed technique, the implementation of magnetic metal-organic framework (MOF) materials for automatic solid-phase extraction has been achieved for the first time. A hybrid material based on submicrometric MOF crystals containing Fe3O4 nanoparticles was prepared and retained in the surface of a miniature magnetic bar. The magnetic bar was placed inside the syringe of an automatic bidirectional syringe pump, enabling dispersion and subsequent magnetic retrieval of the MOF hybrid material by automatic activation/deactivation of magnetic stirring. Using malachite green (MG) as a model adsorption analyte, a limit of detection of 0.012 mg/L and a linear working range of 0.04-2 mg/L were obtained for a sample volume equal to the syringe volume (5 mL). MG preconcentration was linear up to a volume of 40 mL, obtaining an enrichment factor of 120. The analysis throughput is 18 h(-1), and up to 3000 extractions/g of material can be performed. Recoveries ranging between 95 and 107% were obtained for the analysis of MG in different types of water and trout fish samples. The developed automatic D-μ-SPE technique is a safe alternative for the use of small-sized materials for sample preparation and is readily implementable to other magnetic materials independent of their size and shape and can be easily hyphenated to the majority of detectors and separation techniques.

Quantification of morphine, morphine 6-glucuronide, buprenorphine, and the enantiomers of methadone by enantioselective mass spectrometric chromatography in whole blood.

Deaths among drug addicts are frequently caused by intoxication with methadone and/or morphine. These drugs are often used in combination with other drugs, such as buprenorphine. In addition, methadone is generally used as a mixture of R- and S-enantiomers. To date, a method for separation and quantitation of these specific drugs has not been developed. The aim of this study was to develop a sensitive enantioselective method for quantitation of morphine, its active metabolite morphine 6-glucuronide, buprenorphine, and R- and S-methadone, in a single analytical run. Whole blood samples were diluted with 0.5 mol/L ammonium carbonate buffer and extracted on a Bond Elut C18 solid-phase extraction column with an automatic solid-phase extraction system. Chromatographic separation was performed on a chiral alpha-1-acid glycoprotein column with an acetonitrile/ammonium acetate buffer (10 mmol/L, pH 7.0, 22:78 v/v) mobile phase. The whole blood concentrations of the drugs were quantified by mass spectrometry using their stable isotope-labeled compounds as internal standards. The method was validated with respect to specificity, linearity, precision, limits of detection, and quantification and matrix effects. The precision (coefficient of variation) was below 15%, and the accuracy was between 90 and 115%. This method will be useful for routine analyses in forensic laboratories where blood samples are frequently analyzed for drugs of abuse. In some cases, sudden death from methadone overdose is caused by the enantiomeric form of the methadone, which makes the enantiomer separation capability of this method important.

Automated solid-phase extraction coupled online with HPLC-FLD for the quantification of zearalenone in edible oil.

Established maximum levels for the mycotoxin zearalenone (ZEN) in edible oil require monitoring by reliable analytical methods. Therefore, an automated SPE-HPLC online system based on dynamic covalent hydrazine chemistry has been developed. The SPE step comprises a reversible hydrazone formation by ZEN and a hydrazine moiety covalently attached to a solid phase. Seven hydrazine materials with different properties regarding the resin backbone, pore size, particle size, specific surface area, and loading have been evaluated. As a result, a hydrazine-functionalized silica gel was chosen. The final automated online method was validated and applied to the analysis of three maize germ oil samples including a provisionally certified reference material. Important performance criteria for the recovery (70-120%) and precision (RSDr <25%) as set by the Commission Regulation EC 401/2006 were fulfilled: The mean recovery was 78% and RSDr did not exceed 8%. The results of the SPE-HPLC online method were further compared to results obtained by liquid-liquid extraction with stable isotope dilution analysis LC-MS/MS and found to be in good agreement. The developed SPE-HPLC online system with fluorescence detection allows a reliable, accurate, and sensitive quantification (limit of quantification, 30μg/kg) of ZEN in edible oils while significantly reducing the workload. To our knowledge, this is the first report on an automated SPE-HPLC method based on a covalent SPE approach.

Trace analysis of endocrine disrupting compounds in environmental water samples by use of solid-phase extraction and gas chromatography with mass spectrometry detection

A novel analytical method using a continuous solid-phase extraction system in combination with gas chromatography–mass spectrometry for the simultaneous separation and determination of endocrine disrupting compounds (EDCs) is reported. The method was applied to major EDCs of various types including parabens, alkylphenols, phenylphenols, bisphenol A and triclosan in water. Samples were preconcentrated by using an automatic solid-phase extraction module containing a sorbent column, and retained analytes eluted with acetonitrile for derivatization with a mixture of N,O-bis(trimethylsilyl)trifluoroacetamide and trimethylchlorosilane. A number of variables potentially influencing recovery of the target compounds such as the type of SPE sorbent (Silica gel, Florisil, RP-C18, Amberlite XAD-2 and XAD-4, Oasis HLB and LiChrolut EN), eluent and properties of the water including pH and ionic strength, were examined. LiChrolut EN was found to be the most efficient sorbent for retaining the analytes, with ∼100% efficiency. The ensuing method was validated with good analytical results including low limits of detection (0.01–0.08ng/L for 100mL of sample) and good linearity (r2>0.997) throughout the studied concentration ranges. The method exhibited good accuracy (recoveries of 90–101%) and precision (relative standard deviations less than 7%) in the determination of EDCs in drinking, river, pond, well, swimming pool and waste water. Waste water samples were found to contain the largest number and highest concentrations of analytes (3.2–390ng/L)

Quantification of five compounds with heterogeneous physicochemical properties (morphine, 6-monoacetylmorphine, cyamemazine, meprobamate and caffeine) in 11 fluids and tissues, using automated solid-phase extraction and gas chromatography-tandem mass spectrometry.

An automated solid-phase extraction (SPE) protocol followed by gas chromatography coupled with tandem mass spectrometry was developed for quantification of caffeine, cyamemazine, meprobamate, morphine and 6-monoacetylmorphine (6-MAM) in 11 biological matrices [blood, urine, bile, vitreous humor, liver, kidney, lung and skeletal muscle, brain, adipose tissue and bone marrow (BM)]. The assay was validated for linearity, within- and between-day precision and accuracy, limits of quantification, selectivity, extraction recovery (ER), sample dilution and autosampler stability on BM. For the other matrices, partial validation was performed (limits of quantification, linearity, within-day precision, accuracy, selectivity and ER). The lower limits of quantification were 12.5 ng/mL(ng/g) for 6-MAM, morphine and cyamemazine, 100 ng/mL(ng/g) for meprobamate and 50 ng/mL(ng/g) for caffeine. Analysis of real-case samples demonstrated the performance of the assay in forensic toxicology to investigate challenging cases in which, for example, blood is not available or in which analysis in alternative matrices could be relevant. The SPE protocol was also assessed as an extraction procedure that could target other relevant analytes of interest. The extraction procedure was applied to 12 molecules of forensic interest with various physicochemical properties (alimemazine, alprazolam, amitriptyline, citalopram, cocaine, diazepam, levomepromazine, nordazepam, tramadol, venlafaxine, pentobarbital and phenobarbital). All drugs were able to be detected at therapeutic concentrations in blood and in the alternate matrices.

O33: Quantification of morphine, 6-monoacetylmorphine, cyamemazine, meprobamate and caffeine in 11 fluids and tissues, using automated solid-phase extraction and gas chromatography – tandem mass spectrometry

Introduction The present study reports a validated automated solid-phase extraction (SPE) protocol associated to GC-MS/MS assay to quantify 5 drugs (caffeine, cyamemazine, meprobamate, morphine and 6-monoacetylmorphine (6-MAM)) in 11 biological matrices. Assessment of the protocol to be used as a starter set for the development of further analytical assays is demonstrated. Methods Analyses are performed on 200±5 mg of tissue samples for lung, kidney, liver, muscle and bone marrow, 500±10 mg for adipose tissue and brain, and 200μl for biological fluids (bile, blood, urine and vitreous humor). Automated SPE was performed using a Gx-271 ASPEC (Gilson Inc.) on Strata™ X-C (Phenomenex) SPE columns. The molecules were eluted in 2 different eluates, each analyzed by GCMS/ MS. A full validation was performed on BM, the most complex matrix, and partial validation on the other 10 matrices according to the validation protocol proposed by Cartiser et al. (J. Chrom. B, 2011). The sample preparation was assessed in blood, BM and lung for the analysis of 12 further compounds exhibiting varied physicochemical properties: (alimemazine, alprazolam, amitryptiline, citalopram, cocaine, diazepam, levomepromazine, nordazepam, tramadol, venlafaxine, pentobarbital, and phenobarbital). Results Extraction recovery range between 5.3% for morphine in brain to 78.4% for caffeine in bile. The limits of quantification were 12.5 ng/ml(ng/g) for 6-MAM, morphine and cyamemazine, 100 ng/ml (ng/g) for meprobamate and 50 ng/ml(ng/g) for caffeine. Precision and accuracy at the LOQ were respectively less than 20% and between 80% and 120% except for morphine in muscle (121.2%), meprobamate in kidney (138.6%), and cyamemazine in kidney (148.6%). None of the analytes demonstrated precision greater than 15% or accuracy outside of the 85–115% range in BM. Validation on the other matrices showed accuracy of 80–120% for all analytes, except for cyamemazine in kidney where accuracy was 135% at the high QC level. Precision was Conclusion An automated SPE protocol associated to GC-MS/MS analysis was developed for quantification of caffeine, cyamemazine, meprobamate, morphine and 6-MAM in 11 biological matrices. The performance of this assay allows application in forensic toxicology or pharmacokinetic studies. The extraction protocol can be used for targeted analysis of various basic drugs and, with optimization, for other drugs or screening procedures in complex matrices. It could thus be an interesting starting set for further development for laboratories seeking to optimize their activity and confronted to analysis of new compounds or new matrices.

P12 Determination of UR 144, XLR-11 and their metabolites in hair by LC/MS/MS

Introduction Analysis of drugs in hair is often used as a routine method to obtain detailed information about drug ingestion. However, few studies have been conducted on desposition of synthetic cannabinoids including cyclopropylindoles (UR-144 and XLR-11) and their metabolites in hair. UR-144 and XLR-11 have been widely abused and controlled in South Korea recently. Identification of metabolites in hair can be an important proof of synthetic cannabinoids use because it can exclude the possibility of passive smoke exposure. In this study, we described a quantitative method of UR-144 and XLR-11 and their metabolites(UR-144 N -5- hydroxypentyl, UR-144 N -pentanoic acid and XLR-11 4-hydroxypentyl) in hair by liquid chromatography with ESI-MS/MS. Methods The target drugs were extracted in hair by alkaline hydrolysis followed by liquid-liquid extraction(LLE) and solid phase extraction(SPE). After hydrolysis, 1 mL of 0.1 M sodium acetate buffer (pH 4.5) and 0.2 mL of acetic acid were added into hair samples and the samples were extracted with 2 mL of n-hexane:ethyl acetate (9:1). The organic extract was transferred into a disposable test tube and evaporated to dryness at 45 °C under a gentle stream of nitrogen. The extract was reconstituted with 2 ml acetate buffer and SPE was performed using automatic SPE equipment, using hydrophobic and cation exchange SPE column. The extract was evaporated, filtered and analyzed by UHPLC-MS-MS with electrospray ion source in positive-ionization mode. JWH-018-d 9 and JWH-018 N -(5-hydroxypentyl) metabolite-d 5 (50 mL, 100 pg/mL internal standard mixed solution) were used as internal standards for the parent drugs (UR-144 and XLR-11) and their metabolites, respectively. Results Chromatographic separation was completed within 15 min. No interferences were detected in 10 blank hair samples. In intra- and inter-assay precision and accuracy study, CV (%) and bias (%) were below 10. The limit of detection was 0.1 to 2 pg/mg and the limit of quantification was 0.2 to 2 pg/mg, respectively. The validation results proved that the method was selective, accurate and precise with acceptable linearity within calibration range. No significant variation was observed by different sources of matrices. Conclusion This method was applied to hair samples from 17 individual suspects of XLR-11 or UR-144 use. The range of concentration of XLR-11 and UR-144 were 267.8 ~ 5618.8 pg/mg and 0 ~ 7.87 pg/mg, respectively. The range of concentration of UR- 144 N -5-hydroxypentyl and UR-144 N -pentanoic acid were 1.2 ~ 299.5 pg/mg and 0.5 ~ 127.8 pg/mg, respectively. The range of concentration of XLR-11 4-hydroxypentyl was 0 ~ 11.21 pg/mg. UR- 144 N -4-hydroxypentyl was not detected in all cases. We can assume that UR-144 N -5-hydroxypentyl and UR-144 N -pentanoic acid are the major detectable compounds in hair in case of XLR-11 intake.

Occurrence of cytostatic compounds in hospital effluents and wastewaters, determined by liquid chromatography coupled to high-resolution mass spectrometry.

The occurrence of 26 commonly used cytostatic compounds in wastewaters was evaluated using an automated solid-phase extraction (SPE) method with liquid chromatography-high-resolution mass spectrometry (LC-HRMS). Detection was optimized using Oasis HLB SPE cartridges at pH2. Two hospital effluents and their two receiving wastewater treatment plants were sampled over five days. In hospital effluents, eight cytostatics were detected at levels up to 86.2μgL(-1) for ifosfamide, 4.72μgL(-1) for cyclophosphamide, and 0.73μgL(-1) for irinotecan, the three most relevant compounds identified. Cyclophosphamide and megestrol acetate were found in wastewaters at concentrations up to 0.22μgL(-1) for the latter. The predicted environmental concentrations (PEC) in sewage effluents of ifosfamide (2.4-4.3ngL(-1)), capecitabine (11.5-14.2ngL(-1)), and irinotecan (0.4-0.6ngL(-1)), calculated from consumption data in each hospital, published excretion values for the target compounds, and wastewater elimination rates, were in agreement with experimental values.

Analytical method for biomonitoring of perfluoroalkyl acids in human urine

Perfluoroalkyl acids are an important class of synthetic compounds widely used in commercial and residential settings, which may have potential adverse health effects. The objective of this study was to monitor 6 perfluorocarboxylic acids and perfluorooctane sulphonate in human urine to obtain a way to asses exposure. The target analytes were extracted from urine by using a semi automated solid-phase extraction module and derivatised with isobutyl chloroformate by catalysis with 3% N,N-dicyclohexylcarbodiimide in pyridine. Determination and quantisation were achieved by gas chromatography with a mass spectrometer detector operating in the selected-ion monitoring mode. The developed approach is fast and provided low limits of detection (0.2–1.0ngL−1) with good precision (relative standard deviation lower than 7.5%, within-day and between day). Recoveries from urine samples, which were spiked with the studied compounds at levels of 10 and 50ngL−1 ranged from 93% to 96%. Perfluorohexanoic (≤70ngL−1) and perfluoroheptanoic acids (<2ngL−1) were found in the urine samples from exposed researchers taken after handling these compounds. From the calculation of the excretion kinetics it was found that the dosage absorbed was eliminated within 15h after exposure.

Validation of an automated solid-phase extraction method for the analysis of 23 opioids, cocaine, and metabolites in urine with ultra-performance liquid chromatography-tandem mass spectrometry.

The aim of this work was to automate a sample preparation procedure extracting morphine, hydromorphone, oxymorphone, norcodeine, codeine, dihydrocodeine, oxycodone, 6-monoacetyl-morphine, hydrocodone, ethylmorphine, benzoylecgonine, cocaine, cocaethylene, tramadol, meperidine, pentazocine, fentanyl, norfentanyl, buprenorphine, norbuprenorphine, propoxyphene, methadone and 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine from urine samples. Samples were extracted by solid-phase extraction (SPE) with cation exchange cartridges using a TECAN Freedom Evo 100 base robotic system, including a hydrolysis step previous extraction when required. Block modules were carefully selected in order to use the same consumable material as in manual procedures to reduce cost and/or manual sample transfers. Moreover, the present configuration included pressure monitoring pipetting increasing pipetting accuracy and detecting sampling errors. The compounds were then separated in a chromatographic run of 9 min using a BEH Phenyl analytical column on a ultra-performance liquid chromatography-tandem mass spectrometry system. Optimization of the SPE was performed with different wash conditions and elution solvents. Intra- and inter-day relative standard deviations (RSDs) were within ±15% and bias was within ±15% for most of the compounds. Recovery was >69% (RSD < 11%) and matrix effects ranged from 1 to 26% when compensated with the internal standard. The limits of quantification ranged from 3 to 25 ng/mL depending on the compound. No cross-contamination in the automated SPE system was observed. The extracted samples were stable for 72 h in the autosampler (4°C). This method was applied to authentic samples (from forensic and toxicology cases) and to proficiency testing schemes containing cocaine, heroin, buprenorphine and methadone, offering fast and reliable results. Automation resulted in improved precision and accuracy, and a minimum operator intervention, leading to safer sample handling and less time-consuming procedures.

Lead Discovery for Human Kynurenine 3-Monooxygenase by High-Throughput RapidFire Mass Spectrometry

Kynurenine 3-monooxygenase (KMO) is a therapeutically important target on the eukaryotic tryptophan catabolic pathway, where it converts L-kynurenine (Kyn) to 3-hydroxykynurenine (3-HK). We have cloned and expressed the human form of this membrane protein as a full-length GST-fusion in a recombinant baculovirus expression system. An enriched membrane preparation was used for a directed screen of approximately 78,000 compounds using a RapidFire mass spectrometry (RF-MS) assay. The RapidFire platform provides an automated solid-phase extraction system that gives a throughput of approximately 7 s per well to the mass spectrometer, where direct measurement of both the substrate and product allowed substrate conversion to be determined. The RF-MS methodology is insensitive to assay interference, other than where compounds have the same nominal mass as Kyn or 3-HK and produce the same mass transition on fragmentation. These instances could be identified by comparison with the product-only data. The screen ran with excellent performance (average Z′ value 0.8) and provided several tractable hit series for further investigation.

Abstract P244: Urinary Triclosan Concentrations Are Associated with Body Mass Index and Waist Circumference in US Population, NHANES 2003-2010

Introduction: Triclosan, an antibacterial and antifungal agent, is widely used in personal care and household products such as toothpaste. Its effect on human health, however, has not been well investigated. No study has examined the potential consequences of triclosan exposure on obesity traits. Objective: To examine whether triclosan exposure is associated with obesity traits. Methods: This study included 3,659 children (1,884 boys and 1,775 girls, 6-20 years old) and 6,566 adults (3,251 men and 3,315 women, 20 years and older) with detectable levels of urinary triclosan from the 2003-2010 National Health and Nutrition Examination Surveys (NHANES) database. Urinary triclosan concentrations were measured by automated solid-phase extraction coupled to isotope dilution-high-performance liquid chromatography-tandem mass spectrometry. The association of triclosan levels with body mass index (BMI) or waist circumference was examined using multiple linear regression, adjusted for age, race, education, household income, alcohol intake, and cotinine where appropriate. All data analyses were performed using SAS version 9.3 (SAS Institute Inc, Cary, North Carolina), while taking into account sample weights and design variables. Results: Urinary triclosan concentrations were 4.2 μg/g creatinine (95% confidence interval, CI: 3.3-5.3 μg/g creatinine) in boys, 5.1 μg/g creatinine (95% CI: 3.8-6.9 μg/g creatinine) in girls, 9.2 μg/g creatinine (95% CI: 7.4-11.4 μg/g creatinine) in men, and 11.9 μg/g creatinine (95% CI: 9.6-14.8 μg/g creatinine) in women. From the bottom to the top quartile of urinary triclosan concentrations, there was a decreasing trend of BMI in all groups: 22.02±0.33 (multivariable-adjusted mean ± standard error), 21.55±0.28, 21.31±0.27, and 21.16±0.34 kg/m2, p for trend=0.05 in boys; 22.13±0.37, 21.87±0.34, 21.42±0.35, and 20.64±0.23 kg/m2, p for trend=0.009 in girls, 29.24±0.29, 29.07±0.27, 28.73±0.26, and 28.20±0.34 kg/m2, p for trend=0.03 in men; and 29.37±0.40, 28.47±0.43, 29.06±0.39, and 27.07±0.30 kg/m2; p for trend=0.0007 in women. Similar trends were observed for waist circumferences in the four groups (p for trend=0.003-0.04). Conclusion: Triclosan exposure is inversely associated with BMI and waist circumference, independent of multiple risk factors. The biological mechanisms linking triclosan exposure to obesity await further investigation although it is likely that triclosan is an endocrine disrupting chemical.

Simultaneous determination of cotinine and trans‐3‐hydroxycotinine in urine by automated solid‐phase extraction using gas chromatography–mass spectrometry

A gas chromatography–mass spectrometry method was developed and validated for the simultaneous automated solid-phase extraction and quantification of cotinine and trans-3-hydroxycotinine in human urine. Good linearity was observed over the concentration ranges studied (R2 > 0.99). The limit of quantification was 10 ng/mL for both analytes. The limits of detection were 0.06 ng/mL for cotinine (COT) and 0.02 ng/mL for trans-3-hydroxycotinine (OH-COT). Accuracy for COT ranged from 0.98 to 5.28% and the precision ranged from 1.24 to 8.78%. Accuracy for OH-COT ranged from −2.66 to 3.72% and the precision ranged from 3.15 to 7.07%. Mean recoveries for cotinine and trans-3-hydroxycotinine ranged from 77.7 to 89.1%, and from 75.4 to 90.2%, respectively. This analytical method for the simultaneous measurement of cotinine and trans-3-hydroxycotinine in urine will be used to monitor tobacco smoking in pregnant women and will permit the usefulness of trans-3-hydroxycotinine as a specific biomarker of tobacco exposure to be determined. © 2014 The Authors. Biomedical Chromatography published by John Wiley & Sons Ltd.

Rapid determination of technetium-99 by automatic solid phase extraction and inductively coupled plasma mass spectrometry

Technetium-99 (99Tc) is a key nuclide, produced by the fission of uranium-235 (235U) and plutonium-239 (239Pu), through a cascade decay process, and is one kind of target element in environmental analysis due to its long half-life (t1/2 = 2.1 × 105 years).

An alternative to trial and error methodology in solid phase extraction: an original automated solid phase extraction procedure for analysing PAHs and PAH-derivatives in soot

This paper introduces the generalization of reverse-phase HPLC fundamentals to normal-phase liquid chromatography, hydrophilic interaction chromatography (HILIC) and Automated Solid Phase Extraction (A-SPE).

Screening of Danish traffic cases for synthetic cannabinoids in whole blood by LC-MS/MS

ABSTRACT A target screening method for the detection of 13 synthetic cannabinoids in whole blood was developed and validated. Samples underwent automated solid-phase extraction, and sample extracts were analyzed by liquid chromatography-positive electrospray ionization-tandem mass spectrometry using two transitions in multiple reaction monitoring mode. The limit of detection was between 0.1-2.5 ng/mL for the compounds except HU-210, and extraction recovery ranged from 59 to 78%. The method was used to screen 393 Danish traffic cases from 2012, where the driver was suspected of driving under the influence of drugs. No synthetic cannabinoids were identified in these samples. Additionally, the method was applied to a clinical intoxication case, and the synthetic cannabinoid AM- 2201 was identified in serum. We conclude that the prevalence of driving under the influence of synthetic cannabinoids in Denmark is likely to be low, and that synthetic cannabinoids are most likely to be encountered in the clinical setting.

Determination of polychlorinated biphenyls and organochlorine pesticides in small volumes of human blood by high-throughput on-line SPE-LVI-GC-HRMS

A fully automated and robust method featuring on-line solid-phase extraction (SPE) and large volume injection (LVI) gas chromatographic (GC) high resolution mass spectrometry (HRMS) is used to determine polychlorinated biphenyls (PCBs) and organochlorine pesticides, such as penta- and hexachlorobenzene (PeCBz, HxCBz), hexachlorocyclohexane isomers (HCH) and 4,4'-dichlorodiphenyldichloroethene (a metabolite of dichlorodiphenyltrichloroethane (DDT)), with only 200μl of human blood, serum or plasma. After spiking the sample with (13)C-labeled internal standards and precipitating the proteins, the sample is passed through a 10mm×2.0mm ID SPE cartridge filled with C18 material that adsorbs the analytes. After washing and drying, the cartridge is extracted with hexane/dodecane (99/1, v/v); the extract is directly injected into a LVI where GC/HRMS analysis follows. The fully automated system utilizes a robotic autosampler and a modular SPE system including two high-pressure syringe pumps, an automatic SPE cartridge exchanger unit and 6 switchable valves. All sample preparation steps are performed within 20min during the GC run of a previous sample, limiting the throughput with only the GC runtime. The contents are quantified using the isotope dilution method. Due to laboratory air contamination problems, we achieved LOQs of 0.017 (PeCBz), 0.009 (HxCBz), 0.007 (HCH), 0.016 (DDE), while for the six indicator PCBs, we achieved values of 0.030 (PCB-28), 0.044 (PCB-52), 0.024 (PCB-101), 0.009 (PCB-138), 0.015 (PCB-153) and 0.008 (PCB-180)μg/l serum. Under clean laboratory air conditions, these values may be improved. This method is recommended when high throughput is desirable and/or only small amounts of material are available, such as during studies involving children.