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A novel post-synthetic modification of magnetite@MIL-53(Fe)-NH2 core-shell nanocomposite was performed to extract ultra-trace amounts of Pd(II) ions from the real samples. To explore and optimise the effect of parameters on the preconcentration design of the experiment was employed. The highest removal efficiency in the adsorption step was obtained using the following condition: pH of sample, 6.5; adsorption time, 3.8 min; magnetite@MIL-53(Fe)-NH-PITC NPs amount, 20 mg. The highest extraction recovery (%) was achieved using 0.8 mL of 0.85 mol L−1 HCl as the desorbing solution; and by applying an elution time of 3.5 min. Afterwards, to study the equilibrium data, various adsorption isotherm models were explored. The data showed that the Langmuir model describes the adsorption process better than the other models. Eventually, the maximum adsorption capacity and model constant equal to 100 mg g−1 and 0.11 L mg−1, were obtained, respectively. Besides, the kinetic data were well fitted to the pseudo-second-order based on the highest correlation coefficient that was achieved. The limit of detection, the limit of quantification, and the linear range of the proposed method were 0.05 μg L−1, 0.2 μg L−1, and 0.2–100 μg L−1 (r2 = 0.9936), respectively. The precision was explored as relative standard deviation value at three concentration of 0.5, 10, 75 ng mL−1 (n = 3) that was 12.5%, 9.3% and 6.6%, respectively. Ultimately, the new magnetic adsorbent could be employed for extraction/quantification of ultra-trace amounts of Pd(II) ions in real samples and the relative recovery values were obtained in the range of 88–102%. [ABSTRACT FROM AUTHOR]

A simple, rapid and sensitive method for the determination of aflatoxins in peanut oil was developed using MIL-101(Cr) material filled syringe filter for one-step solid-phase extraction (SPE) with high-performance liquid chromatography—tandem mass spectrometry (HPLC-MS/MS) detection. The MIL-101(Cr) sorbent was characterized and its mass, the loading solution, and the eluent were optimized; under these conditions, a matrix matching internal standard method was developed. The linear range was from 0.1 to 20 ng/mL with correlation coefficient (r) exceeding 0.9998. The recoveries were between 94.7% and 105.9% with relative standard deviations from 2.02% 6.88%. The recoveries of inter-day and intra-day measurements were from 93.0% to 98.5% and 97.6% to 100.7%. The precision values for inter-day and intra-day analyses were from 6.09% to 7.68% and 2.56% to 4.30%, respectively. The pretreatment efficiency of the developed method was superior to literature procedures and used to determine aflatoxins in 126 peanut oil samples from local markets. 38 samples had positive results and 1 sample exceeded the allowable limit. Hence, the developed protocol was suitable for the determination of aflatoxins in peanut oil. [ABSTRACT FROM AUTHOR]

A method for determining human epidermal growth factor (hEGF) in cosmetics was developed using solid-phase extraction with high-performance liquid chromatography – tandem mass spectrometry. The sample was extracted and purified by a mixed anionic solid-phase extraction column (MAX), and the eluent was passed through a nylon filter membrane into a polypropylene vial. The matrix-matched external standard method was used to quantify the analyte in multi-reaction monitoring mode. The analyte had an excellent peak shape within 11 min with a linear range from 5 to 80 ng/mL and a linear correlation coefficient (r) of 0.9995. The limit of detection and limit of quantification were 0.75 and 2.5 μg/kg, respectively. The recovery of the target was from 81.5% to 88.8%, and the relative standard deviation was between 1.16% and 5.07%. The results met the International Organization for Standardization 12787 standard. The established method was successfully applied to 30 cosmetic samples. The proposed method is sensitive, accurate, reliable, and suitable for the quantitative confirmation of hEGF and monitoring its illegal addition to cosmetics. [ABSTRACT FROM AUTHOR]

A 30 year old man was found with no signs of life in front of the house. The cyanide concentration in blood and urine was determined five years after the man's death. What is more, a stability study was conducted for 730 days in an authentic casework blood sample. Sample preparation procedure included precipitation with methanol:water mixture, solid phase extraction (SPE) and derivatization with the use of PFB-Br (pentafluorobenzyl bromide). The sample was analyzed using GC-QqQ-MS/MS (gas chromatopraphy coupled with tandem mass spectrometry) isotope dilution method. Separation was done using a SH-RXI-5MS column (30 m x 0.25 mm, 0.25 µm). Detection of PFB-CN and PFB-13CN was achieved using a triple-quadrupole mass spectrometer with an electron ionization (EI) ion source in multiple reaction monitoring (MRM) mode. After 5 years from the man's death, cyanide concentration was: 1900 ng/mL in blood and 500 ng/mL in urine. Stability study performed in an authentic blood sample 6 and 7 years after the man's death revealed cyanide concentrations of 1898.2 ng/mL and 1618.7 ng/mL, respectively. While spectrophotometric and colorimetric methods recorded both decrease and increase in cyanide concentration over time, newer chromatographic methods mainly indicate a decrease. The studies presented in this paper seem to confirm this trend. However, in order to interpretate the results of cyanide concentration in biological material reliably, more research is still necessary. [ABSTRACT FROM AUTHOR]

A rapid and simple magnetic solid phase extraction-liquid chromatography-tandem mass spectrometry method is reported to determine vancomycin in human plasma. The Fe3O4@SiO2 nanocomposite was prepared using silica nanoparticles obtained from rice husk waste and its modification using ammonia solution to obtain a Fe3O4@SiO2-NH2 nanohybrid as a new sorbent. The structure and morphology of the sorbent were characterized by X-ray diffraction, field emission scanning electron microscopy, and Fourier transform infrared spectroscopy. The nanosorbent was successfully used in magnetic solid phase extraction without hazardous solvents in 9 min with analysis by high-performance liquid chromatography – tandem mass spectrometry. Under the optimized conditions, the method provided a linear range from 10 to 1000 ng mL−1. The intra-day (n = 3) and inter-day precision (n = 3 working days) were below 10% relative standard deviation. The developed procedure was employed for determining vancomycin in human plasma with recoveries from 84.0 to 109.5% for spiked samples. [ABSTRACT FROM AUTHOR]

An analytical method based on headspace solid-phase microextraction gas chromatography- ion trap tandem mass spectrometry (HS-SPME-GC-ITMS/MS) was optimised and developed for estimating 20 predominant polychlorinated biphenyl (PCB) concentrations in sediment samples. The effect of experimental parameters involving fibre materials, amount of water added, temperature effect, sorption time, stirring effect, and the addition of solvents were examined with gas chromatography-electron capture detector (GC-ECD). The analytical performance of association of HS-SPME-GC-ITMS/MS proposed methodology was examined by spiked sediment with the selected PCB congeners. The repeatability and reproducibility of measurements (n = 6), expressed with relative standard deviation (RSD), was below 13% and 16%, respectively. Good linearity was observed within the concentration range studied and the LODs were between 0.02 and 0.82 ng g−1. Accuracy was assessed by analysing a reference sediment sample with certified concentrations of several PCBs. Standard addition calibrations were done and concentrations of PCBs with the proposed method were in good agreement with the certified PCB concentrations. The method was also efficiently applied to real sample sediment from Bizerte Harbour, revealing the existence of several congeners at level less than 1.1 ng g−1. These obtained results were also on concordance with analysis of this real sample using a conventional soxhlet extraction method. The developed procedure is highly effective and selective, free of organic solvents, relatively simple and fast, and become a suitable alternative for routine monitoring of residues of PCB from sediments at ultra-trace levels. [ABSTRACT FROM AUTHOR]

The g-C3N4 (GCN) adsorbent with two different morphologies, coral (CGCN) and nano fiber (GCNNF), was synthesized and recruited for extraction and preconcentration of lead and copper metal ions by effervescent salt-assisted dispersive micro solid phase extraction procedure. The structures of the two adsorbents were affirmed by Fourier-transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy and Brunauer–Emmett–Teller analyses. The factors affecting the extraction efficiency were carefully studied and the optimum values of the parameters for both adsorbents were pH 6.5, adsorbent dosage 8 mg, desorption time 3 min, and the elution solvent 300 μL of 2 mol L−1 of HNO3. The detection limits of Pb(II (and Cu(II) ions for CGCN were 0.9 and 0.3 μgL−1 and for GCNNF were 1.56 and 0.7 μgL−1, respectively. The percent relative standard deviations were obtained to be 1.32% and 2.23% for CGCN (n = 3) and 1.24% and 2.29% for GCNNF (n = 3), respectively for the lead and copper metal ions. In addition, the adsorbents could be used up to 7 times without an imperative reduction in the percentages of analytes recovery. Finally, the performance of CGCN and GCNNF were used for preconcentrate of lead and copper ions in honey, canned fish, and human hair samples. [ABSTRACT FROM AUTHOR]

Curry leaf is an evergreen herb with culinary, pharmaceutical, and nutraceutical applications. As pesticide residue in curry leaf has garnered significant regulatory attention in recent years, here we report a reliable method, which was validated for the determination of 265 and 225 pesticides using LC-MS/MS and GC-MS/MS, respectively. At first, the sample was comminuted after adding water (1:2). The sample preparation workflow included extraction of 10 g homogenized sample with 10 mL ethyl acetate (+1% acetic acid), cleanup by dispersive solid phase extraction (d-SPE, 50 mg PSA + 50 mg C18 + 10 mg GCB + 150 mg Na2SO4) and the final analysis by tandem mass spectrometry. The cleanup step adeptly removed co-extractives. The method effectively reduced matrix effects and offered an LOQ of 0.01 mg kg−1 for most compounds. The method's accuracy and precision results fulfilled the requirements of SANTE/11312/2021 guidelines at 0.01 mg kg−1 and higher levels of fortification. The accuracy and precision results were comparable for all pesticides. The successful screening of market samples indicates its high extraction efficiency and precision for incurred residue analysis. Due to its robustness and conformity with regulatory criteria, food testing laboratories worldwide can use the method to monitor pesticide levels in curry leaves. [ABSTRACT FROM AUTHOR]

Liquid chromatography – tandem mass spectrometry (LC-MS/MS) is routinely applied for the determination of toxins associated with diarrhetic shellfish poisoning (DSP) as a part of the Japanese official method. For scallops, not only the edible part but also the midgut gland may be used for analysis. In this study, the matrix effects in the LC-MS/MS-based determination of okadaic acid (OA) and dinophysistoxin-1 (DTX1) in the scallop midgut gland were evaluated to assess the impact on the accuracy of the results. The analyzed sample in an interlaboratory comparison study was subjected to the Japanese official method. The solutions obtained with and without a cleanup process (combination of hexane washing and solid-phase extraction using a C18 cartridge) were diluted to varying ratios and used for evaluation. For all prepared solutions, the ionization of OA and DTX1 was enhanced compared to the samples in methanol; the cleanup process did not sufficiently reduce the matrix effects. Although the dilution of the sample solution reduced the matrix effect, the improvement was limited. Another pretreatment technique is necessary for the accurate determination of DSP-associated toxins in this matrix. [ABSTRACT FROM AUTHOR]

Alpha-methylthiofentanyl and thiofentanyl are psychoactive substances that have been abused in recent years, strongly threatening social and public security. Because they are rapidly metabolized in vivo, their determination presents a great challenge for forensic science. An automated method of online solid-phase extraction coupled with ultra-high performance liquid chromatography—tandem mass spectrometry was developed for the determination of alpha-methylthiofentanyl, thiofentanyl, and the metabolite norfentanyl in urine. The analytes were first enriched and purified by an Oasis HLB online SPE column and eluted on a Hypersil GOLD C18 analytical column. Chromatographic separation was achieved with mobile phase components of 2 mM ammonium formate and 0.1% formic acid in water and same composition in methanol in gradient elution mode. The limit of detection and lower limit of quantitation of the method for the three analytes were 0.2 and 2 pg/ml, respectively. Acceptable linearity was obtained from 2 to 800 pg/ml. The accuracy was in the range of 87.98–108.95%; and precision, calculated as the relative standard deviation, was less than 14.63%. The method recoveries were from 65.56 to 113.72%. This highly sensitive method was applied to study the detection window of the precursor compounds and metabolites in rat urine. Both alpha-methylthiofentanyl and thiofentanyl are metabolized to norfentanyl, which was first revealed in this study. With the aid of norfentanyl, the detection windows of alpha-methylthiofentanyl and thiofentanyl were extended to 18–26 days and 20–27 days, respectively. This study provides important auxiliary tools for the forensic identification of fentanyl analogs. [ABSTRACT FROM AUTHOR]

Per- and poly-fluoroalkyl substances (PFASs) are a class of synthetic organic chemicals that include thousands of compounds. Analytical methods for PFASs in vegetables are limited. In this study, a rapid and sensitive method using on-line solid phase extraction (SPE) coupled with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was developed and validated for the simultaneous determination of 21 PFASs in vegetables. The extraction solvent volume and procedure were optimized to achieve good efficiencies (>93%) using the lowest quantity of solvent. The injection volume, elution condition of the online SPE system, and the mobile phases of the UHPLC-MS/MS system were also optimized to improve the sensitivity, peak symmetry, and resolution. The method detection limits of the 21 targeted PFAS were from 0.001 to 0.008 ng/g and the linearity was from 0.1 to 1000 pg/mL using an injection volume of 5 mL. The validation results indicate that this method is precise, accurate, and robust. Moreover, this method is high throughput (∼15 min per sample); thus, suitable for analyzing a large number of vegetable samples in a short time interval. In addition, the developed method was successfully applied to analyze vegetables. The results show that the total PFAS concentrations were the highest in lettuce, followed by potatoes and tomatoes, and the lowest in broccoli. Different profiles of PFASs were observed among the vegetable species. [ABSTRACT FROM AUTHOR]

The study uses gas chromatography with tandem mass spectrometry (GC-MS/MS) to develop a reliable analytical approach for detecting multiclass pesticides, polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in poultry meat and chicken eggs. The meat (2 g) and egg (4 g) samples were extracted with acidified acetonitrile (10 mL) as part of the optimized sample preparation technique. The cleanup consisted of freezing an aliquot of the extract (5 mL) at −20 °C, followed by dispersive solid phase extraction using 50 mg PSA + 100 mg C18+150 mg MgSO4. The matrix co-extractives were effectively removed and the method performance met the European Commission's analytical quality control criteria (SANTE/12682/2019). The method was validated at two spiking levels (10 and 20 ng/g of 225 pesticides, 9 PAHs and 8 PCBs), and good recoveries (70–120%) and precision-RSDs (≤20%) were achieved for 90% of the targeted pesticide residues. For 80% of the compounds, the LOQs were ≤10 ng/g. The results of the intra-laboratory (involving six analysts) and inter-laboratory validation studies (involving eight ISO 17025 accredited laboratories) established satisfactory ruggedness and reproducibility. It created potential applications in commercial residue testing laboratories for regulatory compliance check purposes. [ABSTRACT FROM AUTHOR]

For routine analytical purpose a method based on a combination of automated solid-phase extraction (SPE) clean-up and detection by Ultra-Performance Liquid Chromatography/Tandem Mass Spectrometry (UPLC-MS/MS) was developed for the determination of pyrrolizidine alkaloids (PA) in various food commodities. In this survey, honey, tea and herbal infusion samples from local retailers collected in 2012–2015 were obtained and analysed for their PA content. PA concentrations were found in 30% of the honey samples and in 42% of the tea and herbal infusion samples with levels up to 595 µg/kg. The survey included 17 individual PA, and their sum is also reported for each sample. [ABSTRACT FROM AUTHOR]

Strawberries are widely cultivated and highly consumed globally, but pests and diseases can severely affect yields. Phenamacril and difenoconazole are high-efficacy pesticides and the mixture of these two pesticides offers a satisfactory option for disease control. In this study, an optimised QuEChERS method combined with dispersive solid-phase extraction purification before injection for simultaneously determining the residues of phenamacril–difenoconazole mixture on strawberries was developed and validated using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC–MS/MS). Average recoveries of phenamacril and difenoconazole in the strawberry matrices ranged from 100% to 104% and 99% to 104%, with relative standard deviations of 2.6%–5.3% and 2.2%–5.5%, respectively. The degradation half-lives of phenamacril and difenoconazole were 3.5–6.6 days and 2.2–3.4 days on strawberries, respectively. Final residues of phenamacril and difenoconazole on strawberries at eight different cultivation regions were 0.033–0.66 mg kg−1 and <0.02–0.089 mg kg−1 after spraying at the maximum dosage recommended by the company of 300 mg a.i. kg−1 twice, respectively. Overall, this study is the first report of phenamacril and difenoconazole residue analysis in strawberries. Therefore, it could provide the reference data for safe management and proper use of phenamacril and difenoconazole in China. [ABSTRACT FROM AUTHOR]

Sulphonamides (SAs) are widely used in animal husbandry. In our work, based on multi-walled carbon nanotubes, a novel residue method was developed for highly sensitive and determination trace levels of sulfamethoxazole, acetyl sulfamethoxazole and aditoprim in edible swine tissues by LC-MS/MS with magnetic solid-phase extraction. The samples were extracted using 2% ammoniated acetonitrile and purified by magnetic solid phase extraction (MSPE). Under the optimal conditions, good linearity was obtained ranging from 5 to 160 μg kg−1. The limits of detection (LOD) and quantification (LOQ) were 2 μg kg−1 and 5 μg kg−1 respectively. The average recoveries were 73.9–94.8% at different spiking levels. The inter-day RSDs were 6.2–10.7% and the intra-day RSDs were 2.4–5.4%. MSPE based on multi-walled carbon nanotubes was a simple and efficient method to enrich and separate the analyses and could be successfully applied for extraction of sulfamethoxazole, acetyl sulfamethoxazole and aditoprim residues in swine tissues. [ABSTRACT FROM AUTHOR]

A method for determining seven microcystins and nodularin in surface water at nanogram per liter concentrations was developed based on on-line solid-phase extraction ultra-performance liquid chromatography – electrospray ionization tandem mass spectrometry (on-line SPE-UPLC-MS/MS). Aliquots of 5 mL water sample were directly injected into on-line SPE after passage through a membrane filter. The water sample was enriched and purified by a hydrophilic–liphophilic balance (HLB) polymeric column and eluted by mobile phase. The analytes were separated by Acquity BEH130 column, detected using tandem mass spectrometry, and quantified by external standardization. Under the optimized conditions, the method detection limits for all of the targets ranged from 1.4 to 3.3 ng/L with the recoveries from 85.5 to 121%. The precision of the method, indicated by the relative standard deviation, was 3.87 to 13.9%. The results of the analysis of surface water samples demonstrated that the proposed method has the ability to determine microcystins and nodularin without the need for complex manual pretreatment. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Solid-phase extraction (SPE) was carefully optimised for preconcentration of 2-4-dimethylaniline (2,4-DMA) and 2,4-dimethylformanilide (DMF) from honey samples. Liquid chromatography with tandem mass spectrometry (LC-MS/MS) was used for the separation and quantification of these analytes. By applying the SPE procedure with 200 mg of OASIS HLB sorbent, the limits of detection achieved in honey samples can be lowered to 0.41 µg·kg−1 for 2,4-DMA and 0.69 µg L−1 for DMF. The proposed method achieves good recoveries (81.1–114%) and precision (RSD 1.07–4.05%, n = 3) for analysed honey sample spiked at two concentration levels 1 µg L−1 and 2 µg L−1. The results demonstrated our method can be applied as a simple way for sample preparation of honey samples for determination of amitraz degradation products. In 1 out of 5 of the analysed Polish honey samples, the DMF residues exceed the maximum residual limits (0.2 mg·kg−1 for total amitraz residues). [ABSTRACT FROM AUTHOR]

This research aimed at implementing and validating a method for analysis of pesticide residues in crops. QuEChERS extraction method with PSA purification was used following analyzes by gas chromatography with tandem mass spectrometry in Selected Reaction Monitoring mode. A short run method was successfully developed for the determination of 41 pesticides, confirmed by two precursor-products for each analyte. The calibration curve for each analyte was linear at concentration range from 1 to 500 μg kg−1 with correlation coefficients higher than 0.99, low limits of detection (0.03 − 10.22 μg kg−1) and satisfactory precision. The developed method was used to investigate apples; mangos; strawberries; cucumbers and tomatoes from the Rio de Janeiro Food Distribution Center (CEASA).Most of the targeted pesticides (78%) were below detection limits. Apple and strawberry presented the highest pesticide contamination levels, many of which are not authorized by tthe Brazilian national regulatory agency (ANVISA). [ABSTRACT FROM AUTHOR]

Solid phase extraction and isotope dilution (ID) liquid chromatography/tandem mass spectrometry (LC/MS/MS) were used to quantify concentrations of oseltamivir phosphate and its metabolite (oseltamivir carboxylate) in addition to four pharmaceuticals (caffeine, carbamazepine, triclosan, triclocarban) in surface waters. Results simultaneously and effectively elucidate the occurrence, fate, and effects of those compounds in surface waters. Higher response intensities of target compounds were obtained using an ultra-purified water/methanol gradient containing 0.01% formic acid with 0.5 mM ammonium acetate as the mobile phase. Methanol/ethyl acetate = 1:4 (v/v) efficiently eluted target compounds from a hydrophilic–lipophilic balanced polymer cartridge. Sample extraction at pH 2.0–3.5 did not affect recovery. This developed method showed satisfactory linearity (r2 > 0.9957) and accurate quantification using ID method with each labelled internal compound. The recoveries from the spiked ultra-purified water and river water samples were 81–127% (1.2–16% relative standard deviation, RSD) and 89–106% (0.4–19%RSD), respectively. The method detection limit was found as 0.2–1.9 ng L−1 from spiked levels of lower concentrations in ultra-purified water. This method, when applied to samples from a small river basin in Akita prefecture, Japan, detected most target compounds at low to high nanogram-per-litre concentrations. [ABSTRACT FROM AUTHOR]

Dimethylsilanediol (DMSD) is a highly water-soluble degradation product of dimethylsiloxane oligomer and polymer materials that may be found in the environment. In this project, we have developed a water analysis method for DMSD based on liquid chromatography-triple quadrupole tandem mass spectrometry (LC/QQQ MS/MS) using 13C-DMSD as an internal standard with and without solid phase extraction (SPE). This included the modification of SPE extraction method for water samples with colloidal particles that may plug the SPE cartridge, the use of a water-based solvent mixture for DMSD elution to promote better ionisation in instrumental analysis and optimisation of instrumental operation conditions for higher sensitivity in QQQ MS/MS analysis. The water method was successfully applied for analysis of DMSD in soil, sediment and biosolids by coupling the water extraction of DMSD from solid samples with the pre-column SPE extraction of the water extracts. The method detection limit (MDL) for direct water analysis was found to be as low as 2 μg L−1, while the current MDLs for sediment, soil and biosolids are in the range of 10 to 100 ng g−1 dw. The matrix spike recovery varied from 79% to 99% for all samples, confirming its general validity of the method. Compared with the published methods, this method requires less sample processing and has lower MDLs for DMSD analysis in environmental samples. [ABSTRACT FROM AUTHOR]

Sterigmatocystin (STC) is a toxic and potentially carcinogenic fungal toxin found in a variety of food commodities. This study describes the development of an analytical method to determine STC in roasted coffee beans and black pepper using ultra performance liquid chromatography (UPLC) coupled with triple quadrupole tandem mass spectrometry (MS/MS). 13C18-STC was used as internal standard. STC was extracted with a mixture of acetonitrile/water, diluted with a buffer, followed by purification with a solid-phase extraction and an immunoaffinity column prior to the UPLC-MS/MS analysis. Two multiple reaction monitoring (MRM) transitions were employed, one for quantification and one for confirmation of STC. The UPLC-MS/MS analytical method was validated with respect to selectivity, linearity, sensitivity, accuracy, precision, recovery, and stability. Calibration curves were linear over a concentration range 25–2,500 pg mL−1 with correlation coefficients (r) > 0.998. The method limit of quantification for STC in roasted coffee beans and black pepper was 0.10 μg kg−1. The accuracy and precision of the analytical method were acceptable within 15% at all quality control levels. This method was suitable to determine STC levels because of its selectivity, precision, and accuracy. The method was successfully applied to roasted coffee beans and black pepper samples. [ABSTRACT FROM AUTHOR]

An analytical method was established to simultaneously determine prochloraz and three metabolites N-propyl-N-[2-(2,4,6-trichlorophenoxy)ethyl] urea(BTS44595), N-formyl-N-propyl-N-[2-(2,4,6-trichlorophenoxy)ethyl] urea(BTS44596), and 2,4,6-trichlorophenol(BTS45186) in fruits and vegetables. The analysis was performed by liquid chromatography – tandem mass spectrometry (LC-MS/MS) in the positive and negative ion-switching multiple reaction modes (MRM). The analytes were extracted using acetonitrile. The extract was further purified by dispersive solid phase extraction. The linearity of the matrix-matched calibration curves was verified with correlation coefficients (r) greater than 0.9975. Recoveries in fruits and vegetables were conducted at four appropriate concentrations. The average recoveries of the method ranged from 80% to 105%, and the relative standard deviations were less than 15%. The limits of detection and quantification of the analytes in fruits and vegetables were from 0.1 to 1 µg/kg and 0.5 to 5 µg/kg, respectively. The method was validated and demonstrated to be suitable for the determination of prochloraz and three metabolites in fruits and vegetables. [ABSTRACT FROM AUTHOR]

Gynura procumbens is commonly consumed as a vegetable and has been approved as an ingredient for food and dietary supplements in China. However, Gynura species are known to contain toxic pyrrolizidine alkaloids (PAs) and the PA profiles in G. procumbens are not known. This study was to extract and enrich PA from G. procumbens or health care products using PCX solid-phase extraction (SPE) cartridges identify the main PAs in the herb and to develop an liquid chromatography–mass spectrometry (LC-MS/MS) method for assaying the PA contents in the plant and its derived products. Upon using multiple reaction monitoring (MRM) acquisition together with comparison to the characteristics of mass fragmentations and retention times of reference standards, 11 PAs were identified as the main PAs in the plant. After clean-up and enrichment with PCX solid-phase extraction (SPE) cartridges, which resulted in better PA recoveries than either C18 or SCX cartridges, the LC-MS/MS method was subjected to validation in terms of linearity, repeatability, limits of quantification (LOQ) and recovery. The validated method was applied to quantify PAs in 12 plant samples and 7 commercial finished products. The total amounts of targeted PAs were found to vary from 15.6 to 848 μg/kg in the herbs and from 9.9 μg/kg to 33.9 mg/kg in the commercial products. The present work was the first to demonstrate that G. procumbens contained PAs in the herb and its derived products and the PA contents might exceed the daily dose limits in food and herbal medicinal products proposed by the European Medicines Agency (i.e. 0.35 μg PA per day for 50 kg adult). [ABSTRACT FROM AUTHOR]

Fluoroquinolones are in the order of the day concerning environmental contamination through anthropogenic activities, resulting in increased risk for antibiotic resistance dissemination. In this context, accessible, low-cost analytical methods are required for implementation of comprehensive surveillance and screening schemes. In this work, we propose a down-scaled disk-based solid-phase extraction system from which the eluate can be first screened by miniaturized fluorimetric reading, followed by individual determination of target fluoroquinolones (ciprofloxacin, norfloxacin, and enrofloxacin) by liquid chromatography combined to tandem mass spectrometry. The fluorimetric measurement is based on the intrinsic fluorescence of fluoroquinolones. Disk-based retention was performed after sample acidification (pH 4.0) by mixed-mode cation exchange using polystyrene divinylbenzene sulphonated sorbent. Sample loading was precisely controlled in a dedicated flow system operating at 4.0 mL min−1. Different eluent compositions were tested, with elution performed by 1.00 mL of methanol-ammonium hydroxide (98:2, v/v), with subsequent reading of eluate in both detectors. Quantification was attained for 2–25 µg L−1 range, with LOD values at 1 µg L−1. The proposed approach was successfully applied to estuarine waters from the Douro River, with comparable results to a conventional SPE-LC-MS/MS procedure. [ABSTRACT FROM AUTHOR]

In this study, a convenient and sensitive analytical method based on dispersive solid-phase extraction (dSPE) and gas chromatography-tandem mass spectrometry in tandem was developed for the simultaneous determination of six chloroacetamide herbicides (acetochlor, alachlor, metolachlor, metazachlor, butachlor and pretilachlor) in soil. Parameters that could influence the extraction efficiency such as the varieties of solvents, the amount of solvents and sorbents were investigated. The optimized extractions were performed by mixing 5.0 g of dried soil with 10.0 mL acetonitrile, 10.0 mL deionized water and 4.0 g sodium chloride, and then the extract was purified with 50.0 mg N-propyl ethylenediamine (PSA), 50.0 mg C18, 10.0 mg graphitized carbon black (GCB) and 100.0 mg MgSO4 (5:5:1:10). At 5.0, 25.0 and 100.0 ng g−1 fortification levels for each analyte, the average obtained recoveries ranged from 87.7% to 108.0% with relative standard deviation (RSD) between 3.8% and 10.9%. The soil matrix effect of the six compounds were lower than 11.0%. The linear relation was observed in the range of 5.0–500.0 ng g−1 and the correlation coefficient (R2) of these compounds were higher than 0.998. The detection limits (LODs) were in the range of 0.2–1.0 ng g−1, and the limits of quantification (LOQs) were between 0.8 and 2.2 ng g−1. Comparing with the gas chromatography-electron capture detector (GC-ECD), the GC-tandem mass spectrometry (MS/MS) method can improve the anti-interference ability and thus get better separation of the chloroacetamide herbicides. Additionally, this method was verified to fit for soil samples with broad organic matter range (16.2 to 83.0 g kg−1). The developed method was successfully applied for analysing 26 field soil samples collected from Dianchi lake basin in the southeast of China. About 42.0% soil samples were detected with these herbicides, of which butachlor was the most frequently detected and the highest concentration was up to 137.0 ng g−1 in rape soil. [ABSTRACT FROM AUTHOR]

The illicit use of β-blockers in food-producing animals may induce the presence of these compounds in meat and milk. The presence of β-blockers in these foods is a safety issue. A simple and economic high-performance liquid chromatography - tandem mass spectrometry method was developed and validated for β-blockers in bovine and porcine muscle, kidney, liver, and bovine milk. The focus of the study was on the detection and quantitation of acebutolol, atenolol, betaxolol, carazolol, metoprolol, nadolol, penbutolol, and propranolol. Homogenized tissues were digested with glucuronidase/aryl sulfatase to release the analytes that were extracted with acetonitrile and purified using matrix solid-phase dispersion. For residues in milk, acidolysis and extraction utilized trichloroacetic acid and acetonitrile and the samples were purified using mixed-mode cation exchange solid phase extraction. Standard curves generated using homogenized tissues and milk matrices were linear with correlation coefficients exceeding 0.99. The limits of detection and quantification were 1 μg/kg and 2.5 μg/kg, respectively, for all analytes in the meat tissues. The corresponding values for milk were 0.2 μg/kg and 0.5 μg/kg. The average recoveries of the spiked samples were from 84.4 to 114.2% with the standard deviations of the intra- and inter-day assays from 2.0 to 14.6% and 2.9 to 18.7%, respectively. This method is simple, economical, and time-saving for the determination of β-blockers in bovine tissue, porcine tissue, and bovine milk. [ABSTRACT FROM AUTHOR]

A practical multi-residue method based on ultra-performance liquid chromatography/tandem mass spectrometry was developed for the simultaneous determination of 23 perfluorinated alkylated substances (PFASs) in water and suspended particles. Suspended particle samples were extracted with 1% formic acid-acetonitrile and cleaned by matrix solid phase dispersion extraction using a C18 sorbent and graphitized carbon black. Water samples were filtered through 0.7-μm glass fiber membranes and enriched utilizing weak anion exchange cartridges. The eluent was dried under a gentle stream of N2 at 45°C and suspended in 1 mL acetonitrile-5 mM ammonium acetate (1:1, vol:vol). Gradient elution for chromatographic separation utilized acetonitrile and 5 mM ammonium acetate as mobile phases on a reverse phase C18 column. The compounds were quantified using an internal standard method in multiple reaction-monitoring mode. Limits of detection and quantitation of the 23 PFAS test compounds in water samples were 0.5-10 ng L−1 and 2-20 ng L-1, respectively. Recoveries at three fortified levels of 20, 50, and 200 ng L-1 ranged from 68.5% to 118% with relative standard deviations below 9.6%. We used this method to determine PFAS levels in real water and suspended particle samples and found high sensitivity and good reproducibility. [ABSTRACT FROM AUTHOR]

A sensitive LC-MS/MS method for the determination of glyphosate in beer has been developed, validated, and applied to analyse 100 beer samples from 24 different producers and distributors in Latvia. The selected samples represented most beer brands and varieties sold in local supermarkets. Different procedures for sample preparation and chromatographic separation were compared. The final version of the method consisted of solid phase extraction, chromatographic separation on aminopropyl stationary phase, and detection using tandem mass spectrometry. The concentration of glyphosate in beer varied from below the LOD of 0.2 μg kg−1 up to 150 μg kg−1, higher than previously reported. Significantly higher (p < 0.01) content of glyphosate was observed in beers that did not have the country of production disclosed on the label and were sold in local supermarkets by distributors from Latvia (1.8 μg kg−1 median concentration in locally produced beer, 6.7 μg kg−1 in beer of undisclosed origin). [ABSTRACT FROM AUTHOR]

Atmospheric samples have been collected between 14 March and 12 September 2012 on a 2-week basis (15 days of sampling and exchange of traps each 7 days) in Strasbourg (east of France) for the analysis of 43 pesticides. Samples (particle and gas phases) were separately extracted using Accelerated Solvent Extraction (ASE) and pre-concentrated by Solid Phase Micro-Extraction (SPME) before analysis by gas chromatography coupled to tandem mass spectrometry (GC-MS/MS). Four SPME consecutive injections at distinct temperatures were made in order to increase the sensitivity of detection for the all monitored pesticides. Currently used detected pesticides can be grouped in four classes; those used in maize crops (acetochlor, benoxacor, dicamba, s-metolachlor, pendimethalin, and bromoxynil), in cereal crops (benoxacor, chlorothalonil, fenpropimorph, and propiconazole), in vineyards (tebuconazole), and as herbicides for orchards, meadows of green spaces (2,4-MCPA, trichlopyr). This is in accordance with the diversity of crops found in the Alsace region and trends observed are in accordance with the period of application of these pesticides. Variations observed permit also to demonstrate that the long time sampling duration used in this study is efficient to visualize temporal variations of airborne pesticides concentrations. Then, long time high-volume sampling could be a simple method permitting atmospheric survey of atmospheric contamination without any long analysis time and consequently low cost. [ABSTRACT FROM AUTHOR]

A highly sensitive and reproducible method without derivatization is reported for the determination of abscisic acid, gibberellin A3, gibberellin A4, indole-3-acetic acid, zeatin, and zeatin riboside in Masson pine (Pinus massoniana L.). The method combined accelerated solvent extraction, solid-phase extraction, and high-performance liquid chromatography with electrospray ionization-tandem mass spectrometry to determine these hormones. The optimal conditions for accelerated solvent extraction were 4:1 methanol/water acidified with 1.0% glacial acetic acid as the solvent with three 15-min cycles at 25°C and 1300 psi. The recoveries from the pine samples were from 86.8 to 105.4%. The limits of detection were from 0.005 ng L-1 for abscisic acid to 0.500 ng L-1 for gibberellin A4. The intraday precision values were 2.2-7.7%, with interday precision from 3.3 to 10.6% for all analytes. The developed method allows the identification and determination of endogenous hormones in tree samples. [ABSTRACT FROM AUTHOR]

A method for the determination of methylparaben, ethylparaben, propylparaben, butylparaben, and benzylparaben is reported. A polymeric cartridge containing ultra-pure polystyrene cross-linked with 50% divinylbenzene and 50% poly(methyl methacrylate) was employed for the isolation of parabens from water samples. The extracted samples were analyzed by high-performance liquid chromatography coupled with tandem mass spectrometry. The limits of detection for the method were from 0.3 to 2.9 ng L−1that allowed the determination of parabens in river and lake water samples with suitable precision and accuracy. There was high variability in the results depending on time of sample collection. The highest concentrations were obtained for samples collected in July – up to 466 ng L−1of methylparaben and 144 ng L−1of propylparaben. [ABSTRACT FROM PUBLISHER]

Sulfo-functionalized iron oxide magnetic nanobeads were employed as an adsorbent for magnetic solid-phase extraction of benzodiazepines in beef. The analytes were determined by high performance liquid chromatography–mass spectrometry. The sulfo-functionalized iron oxide magnetic nanobeads were characterized by transmission electron microscopy and infrared spectroscopy. The optimal pH, ionic strength, volume of sulfo-functionalized iron oxide magnetic nanobeads, and elution solvent were investigated for the isolation procedure. Under the optimized conditions, the limits of detection for diazepam, oxzepam, triazolam, and chlordiazepoxide were 0.79, 0.22, 0.13, and 0.23 ng/kg, respectively. The method was employed for the determination of the analytes in beef. Compared with established methods, magnetic solid phase extraction and high-performance liquid chromatography–tandem mass spectrometry method exhibited high sensitivity, rapid separation, and low cost. [ABSTRACT FROM PUBLISHER]

Methamphetamine is one of the most widely used sympathomimetic amines in Asia. To identify cases of methamphetamine abuse and to estimate its abuse, hair segmental analysis is used extensively. However, existing hair analysis has several limitations due to matrix interferences. In an attempt to resolve these issues, a simple, rapid, and sensitive liquid chromatography–tandem mass spectrometry method is reported for the determination of methamphetamine and amphetamine in human hair with anion exchange solid phase extraction. Hair dissolved in sodium hydroxide was loaded on a mixed-mode anion exchange cartridge and amphetamine and methamphetamine were eluted with methanol in less than ten minutes followed by liquid chromatography–tandem mass spectrometry. The recovery of this method was between 93.9 and 102.0 percent. The limits of detection and quantitation were 0.01 and 0.05 nanograms per milligram for both analytes. The accuracy and precision were satisfactory for quantitative analysis. The suitability of the method for practical analysis was investigated using hair from methamphetamine users. [ABSTRACT FROM PUBLISHER]

This study features the simultaneous extraction and quantification of 18 pharmaceuticals and personal care products (PPCPs). This is a pioneering method for the quantification of acetaminophen, sulfamethoxazole, diclofenac, atenolol, metoprolol, diethyltoluamide and oxybenzone in atmospheric pressure chemical ionisation mode. The method was validated for high repeatability and reproducibility with relative standard deviations less than 10%. Instrument quantification limits for PPCPs were within the range of 0.05–1.0 µg L−1, and the method quantification limits (MQLs) for ultrapure water were within the range of 0.3–15 ng L−1. All samples were extracted using Oasis© hydrophilic–lipophilic balanced cartridges with optimised sample size and extraction conditions. Good accuracy was demonstrated, with solid-phase extraction recoveries above 80% for most PPCPs. In environmental matrices, the MQLs for river water, sewage treatment plant (STP) effluent and STP influent were 4–25, 10–153 and 38–386.5, respectively. The method was successfully applied to investigate occurrences of persistent PPCPs in Malaysian river and sewage samples. [ABSTRACT FROM PUBLISHER]

A fast and reliable ultra-high performance liquid chromatography–tandem mass spectrometry method was developed for the determination of aflatoxins B1, B2, G1, and G2in cereal. The analytes were extracted by accelerated solvent extraction with methanol/water (80:20). A polymeric solid-phase extraction column was used for sample preparation. Under optimum conditions, the analyte recoveries for samples spiked at different concentration levels in rice and maize ranged from 71.2 to 94.0%, with relative standard deviations less than 16.4%. Limits of detection (signal-to-noise ratio, 3:1) for the aflatoxins ranged from 0.25 to 0.93 ng/g. The developed method was applied to the determination of aflatoxins in ten rice and maize samples. One maize sample tested positive with an aflatoxin B1concentration of 2.7 ng/g. [ABSTRACT FROM PUBLISHER]

An on-line solid-phase extraction (SPE) ultrahigh-pressure liquid chromatography tandem mass spectrometry method was developed and validated for the simultaneous determination of the bisphenol A, bisphenol AF, tetrachlorobisphenol A, and tetrabromobisphenol A concentrations in water samples. The on-line SPE system used a 10 µm particle size SPE column to concentrate the analytes and was coupled with a 1.7 µm particle size chromatographic column for analysis. The total analysis time for each sample using this process was only 12 min, and the method limit of quantification (MLOQ) ranged from 1.5 to 53 ng/L for different water matrices when a 2.5 mL sample was injected. Isotopic internal standard calibration was used to compensate for matrix effects in the trace-level analysis using mass spectrometry. The method has good precision (RSD < 14.1%) and accuracy (spiked recoveries ranging from 85.1% to 110.8% at three spiking levels). Finally, this method was successfully used to analyse real environmental water samples from the Jiaxing region of Hangzhou Bay. [ABSTRACT FROM AUTHOR]

In this study, a highly sensitive analysis method was developed for measuring the ng L−1levels of nine nitrosamines in various water samples. Comparison of recoveries calculated by using four different cartridge types of solid-phase extraction (SPE) indicated that the UCT activated carbon cartridge combined with the HLB cartridge showed the highest recoveries for all target nitrosamines with over 70% recoveries except NDPhA (∼ 50%). To optimise the mass spectrometric conditions, the sensitivity of nitrosamines applying atmospheric pressure chemical ionisation (APCI) and electrospray ionisation (ESI) was tested, and the APCI mode showed 2–20 times higher sensitivity. The method developed in this study was evaluated with certified reference material (CRM), and the result showed good accuracies of 83.3–98.4%. Using the optimised method, nine nitrosamines were analysed in the wastewater of the sewage treatment plants and rivers. The influents showed the highest total concentrations (3061–28,268 ng L−1), followed by the effluents (32.3–339 ng L−1) and river water (106–300 ng L−1). [ABSTRACT FROM AUTHOR]

Lotus(nelumbo)is a traditional Chinese medical herb, and alkaloids are responsible for its pharmaceutical activities. Therefore, a rapid, validated method to determine alkaloids in lotus leaves is useful for its quality control. The goal of this work was to develop and validate an analytical method for the identification and quantitation of the bioactive alkaloids of extracts from lotus leaf and classification of lotus germplasm based on alkaloid concentrations. Solid-phase extraction was used prior to high-performance liquid chromatography coupled with photodiode array detection at 272 nm and tandem electrospray ionization triple quadrupole mass spectrometry for analysis. Nuciferine andO-nornuciferine were the dominant compounds in lotus used for seed production and some used for flower production. However, anonaine, roemerine, andN-nornuciferine were abundant only in some lotus flowers. All the lotuses were classified into four groups by principal component analysis of alkaloid content: 10 flower and three seed lotuses characterized by high nuciferine andO-nornuciferine content; 12 flower lotuses with highN-nornuciferine, roemerine, and anonaine content; two flower lotuses with a relatively high content of all five alkaloids; and cultivars with a low alkaloid content and without dominant alkaloids. [ABSTRACT FROM PUBLISHER]

A multi-residue method using liquid chromatography coupled to triple quadrupole tandem mass spectrometry (LC-MS/MS), associated with solid-phase extraction (SPE), was developed for the determination of 21 pesticides in water samples. The compounds investigated are used for the maintenance of golf courses and ordinarily measured by gas chromatography-mass spectrometry (GC-MS). Electrospray ionisation (ESI) was applied to all compounds, and LC and MS conditions were optimised to measure them under SRM mode. This method showed excellent linearity ranges for all pesticides, with correlation coefficients greater than 0.996. Two kinds of extraction cartridges, namely, styrene divinylbenzene polymer (Sep-Pak PS-2) and divinylbenzene-N-vinylpyrrolidone copolymer (Oasis HLB), were tested and the extraction conditions were optimised. All the pesticides were determined using acetonitrile and ethyl acetate as eluents in both cartridges, and good recoveries (>77%) and repeatability with low relative standard deviations (RSDs, <12%) were achieved from ultra-pure water. In addition, satisfactory recoveries (>76%) and low intra-day and inter-day RSDs (<15%) of all pesticides were also obtained with the Sep-Pak PS-2 cartridge when using river water. The method limits of detection (LODs) ranged between 0.068 (diazinon) and 3.9 (triclopyrbutoxyethyl) ng L−1. The analytical method was successfully applied for the determination of pesticides in surface river water. [ABSTRACT FROM AUTHOR]

This study describes a procedure for the determination of two textile dyes (Nylosan Red N-2RBL-azo and Optilan Blue MF-GL-anthraquinone) from wastewater by solid phase extraction and liquid chromatography/electrospray ionization tandem mass spectrometry (SPE-LC/ESI-MS/MS) analysis. Four types of Strata SPE cartridges (C18-U, C18-E, WAX/NH2, and SAX) were tested; the best results being obtained on Strata WAX/NH2. The detection of dyes was carried out by mass spectrometry with an API 3200 QTRAP ESI-MS/MS system using a TurboV ionization source in ESI negative ion mode. The method of multiple reaction monitoring transitions was followed to quantify the precursor molecular ions and the related product ions. A mobile phase of methanol:water (70/30,v/v) at 0.65 mL min−1flow rate was used for elution. The procedure was validated by: linearity, limits of detection and quantification, accuracy, and precision. The obtained detection/quantification limits were: 0.285/0.864 ng mL−1for Nylosan Red N-2RBL and 0.433/1.310 ng mL−1for Optilan Blue MF-GL. The presented procedure has been applied for monitoring the studied textile dyes in influent and effluent wastewater from a treatment plant from an area in Romania that has a textile factory. [ABSTRACT FROM AUTHOR]

A novel, sensitive, and robust method has been developed to detect 9 β2-agonists in porcine urine to monitor illegal use of β2-agonists in swine rearing. The method based on the molecular imprinted polymer (MIP) rapid extraction followed ultra-performance liquid chromatography coupled tandem mass spectrometry (UPLC-MS/MS) detection. The cleaning efficiency of MIP cartridges was demonstrated by comparing with common ion exchange solid phase extraction. The presented method was validated in accordance with the European Commission Decision 2002/657/EC. The linearity, decision limit (CCα), detection capability (CCβ), recovery, precision, robustness, and stability were studied in detail. CCα and CCβ values were from 0.006 ng/mL to 0.03 ng/mL and from 0.02 ng/mL to 0.08 ng/mL, respectively. The mean recoveries and repeatability varied from 68.8% to 94.2% and from 2.8% to 10.1%. The proposed method was applied to test 170 porcine urine samples from the Shaanxi province in China and two urine samples were confirmed as clenbuterol positive and the concentrations of clenbuterol in positive urine samples were about 0.08 ng/mL and 0.1 ng/mL, respectively. The developed method was demonstrated to be more sensitive and robust for the determination of 9 β2-agonists in porcine urine. The method was proven to be simple and easy in operation with high selectivity and good reproducibility. [ABSTRACT FROM PUBLISHER]

This paper presents new reversed phase liquid chromatographic methods (HPLC-FLD and LC-MS/MS) for the quantification of sulfonamides in spiked and incurred honey samples. The sample preparation was optimized using Oasis HLB (hydrophilic–lipophilic balance) solid-phase extraction (SPE) cartridge. Elutions of sulfonamides were carried out under acidic, neutral, and basic conditions using methanol. Recoveries under acid condition were in the range from 66.8–90%, which were approximately 10% higher than those obtained under other conditions. The sample clean-up was also tested using Strata-XL cartridges. The HPLC-FLD separation was performed using a Varian C18 column and a ternary (methanol-acetonitrile-phosphate buffer, pH 5) mobile phase resulting good selectivity for the determination. The robustness of the ternary gradient method was evaluated by computer simulation (DryLab). LC-MS/MS separation was carried out on a Kinetex XB core-shell type HPLC column that enabled a low limit of detection (0.01–0.5 µg/kg) and faster separation (6 min). The developed methods were validated in accordance with the European Union Commission Decision 2002/657/EC and were applied successfully for more than four hundred honey samples (under a national monitoring program). The concentrations of sulfadimethoxine, sulfachloropyridazine, and trimethoprim residues in samples were found in a concentration range from 0.03 up to 686 µg/kg. [ABSTRACT FROM PUBLISHER]

An analytical method was developed for the simultaneous extraction and determination of 18 fluoroquinolones (FQs), tetracyclines (TCs) and sulfonamides (SAs) antibiotics from soils using solid phase extraction and liquid chromatography-tandem mass spectrometry. The soils were extracted by different solvents with the help of mechanical shaking and ultrasonic treatment at 59 kHz, followed by a strong anion exchange (SAX) cartridge to clean up soil samples and a hydrophilic lipophilic balance (HLB) cartridge as enrichment. The method was evaluated by testing the following variables: extraction solvents, the type of SPE cartridges, solvent volumes, initial spiking levels and soil types (silty clay loam and clay loam soils). The soil extraction method was validated using these two types of soils, representing two typical agricultural soils in northern China. For 2 g soil, the extraction steps with the mixture of potassium phosphate buffer and acetonitrile (ACN) (1/1, v/v, pH 3.2) provided satisfactory recoveries. In the clay loam soil, the recoveries of all the compounds were from 56% to 89% at the spiking level of 50 µg kg−1 soil, and from 69% to 97% at the spiking level of 200 µg kg−1 soil, respectively. Recoveries in silty clay loam soil were similar to that in clay loam. The method was successfully employed using soil samples collected from a farmland and afforestion area irrigated with sewage in northern China. The result indicates that trace antibiotics in sewage may accumulate in soil irrigated by river water containing sewage. [ABSTRACT FROM AUTHOR]

A method basing on liquid chromatography–mass spectrometry (LC-MS/MS) was developed for sensitive determination of Organophosphorus pesticides namely Monochrotophos, Quinalphos and Chlorpyrifos in okra in Andhra Pradesh (South India). The method involves extraction of 10 g of homogenized okra samples (2 g of Sodium chloride + 8 g of Magnesium sulfate) with 10 mL of acetonitrile later cleaned up by dispersive solid phase extraction with the combination of primary secondary amine (PSA), graphitized carbon black (GCB), C18, and anhydrous magnesium sulfate. Final analysis was performed by liquid chromatography-electro spray ionization–tandem mass spectrometry operated in the multiple reaction monitoring (MRM) mode, acquiring two specific precursor-production transitions per target compound. The average recoveries measured at 10 µg/kg were in the range 81–106% for all of the compounds tested with relative standard deviations below 14%. The methodology has been proven to be highly efficient and robust and thus the method is highly suitable for monitoring the Maximum Residue Limits (MRL) compliance of the pesticides. [ABSTRACT FROM AUTHOR]

A detailed analytical study on ethephon residue determination in water, making use of ion-pairing liquid chromatography coupled to electrospray tandem mass spectrometry (LC/MS/MS), has been carried out. Ethephon is a plant growth regulator, highly polar, which is typically present in aqueous solution in anionic form due to its acid character. Both its extraction and pre-concentration from water samples and its chromatographic retention are difficult. Several approaches for sample pretreatment have been tested including direct injection into the chromatographic system, on-line solid phase extraction (SPE) and off-line SPE, with the best results being obtained after off-line SPE, using Oasis MAX cartridges (mixed-mode strong anion-exchange). After testing several ion-pairing reagents, tetrabuthylammonium acetate (TBA) was selected. This was added to the samples before LC/MS/MS analysis to facilitate ethephon chromatographic retention. The acquisition of several specific MS/MS transitions together with the evaluation of their relative intensity ratios allowed the reliable confirmation of the analyte in samples. The optimised approach was tested in low-salinity water spiked at 0.1 µg L−1 level with satisfactory recovery, and a limit of detection of 0.02 µg L−1. To this purpose, the water sample was partially de-ionised in an initial stage, in order to remove major ions that would have interfered in analyses. The application of this methodology to more saline/complex water samples, as surface or wastewater, was problematic and a thorough optimisation of the de-ionisation conditions would be required. [ABSTRACT FROM AUTHOR]

A rapid, simple, and sensitive liquid chromatography tandem mass spectrometric (LC-MS/MS) method for the determination of clopidogrel in human plasma was developed and validated using clopidogrel-d4 as the internal standard (IS). The analyte and the IS were extracted from 500 µl aliquots of human plasma via solid phase extraction. The precursor to product ion transitions monitored for clopidogrel and IS were m/z 322.2 → 212.0 and 326.2 → 216.0, respectively. The method was fully validated for sensitivity, accuracy and precision, linearity, recovery, matrix effect, dilution integrity, and stability. The Linearity range was 20.4-10,772.6 pg/mL with mean correlation coefficient ( r) ≥ 0.9977. The back conversion was also evaluated during method validation as per EMA recommendation. Results proved that clopidogrel was accurately and reliably estimated by the method without any evidence of back conversion of clopidogrel acid. The method was successfully applied to a bioequivalence study of 75 mg clopidogrel bisulfate tablet formulation in 32 healthy male volunteers under fasting conditions. The ratios of least-squares means (with 90% confidence intervals) for the pharmacokinetic parameters Cmax, AUC0- t and AUC0-α were 107.98% (94.52-123.35%), 100.25% (91.28-110.09%), and 100.49% (91.37-110.51%), respectively. [ABSTRACT FROM AUTHOR]

In this study, liquid chromatography–mass spectrometry was used to quantify the concentrations of residues of bacitracin A in extracts obtained from pork liver, kidney, and muscle tissues. Tissues were homogenized with acidic methanol/water and centrifuged. The supernatant was decanted, diluted with water, and loaded onto a conditioned solid phase extraction (SPE) cartridge. Bacitracin A was eluted from the SPE with methanol. After evaporating the methanol to dryness, the residual extract was reconstituted in the mobile phase for quantitative analysis by LC-MS. The limit of Quantification (LOQ) for the method was 100 ng/g. Any samples eliciting quantifiable concentrations ≥100 ng/g were subjected to confirmatory analysis by LC-MS/MS. [ABSTRACT FROM PUBLISHER]

A solid phase extraction (SPE) technique for seawater samples coupled to quantification using liquid chromatography tandem-mass spectrometry (LC-MS/MS) is described to quantify relevant antifouling booster biocides of ecotoxicological concern (Diuron, TCMTB, Irgarol 1051 and Dichlofluanid). The optimised methodology provides a sensitive, easy to use and efficient analytical procedure with detection limits in the range of between 0.1 and 0.2 ng L−1 and appropriate reproducibility (with analytical standard deviations of less than 10%). Spiked recoveries for all compounds exceeded 72%. The method was tested through a thorough monitoring regime of commercial port and marinas on the island of Gran Canaria (off the north-west coast of Africa) over a period of several months in 2008. Results provide the first data for antifouling booster biocides in the Canary Islands. Concentrations of Diuron and Irgarol 1051 in samples ranged between 2 and 195 ng L−1 and 2 and 146 ng L−1, respectively. TCMTB and Dichlofluanid were not detected. [ABSTRACT FROM AUTHOR]

This paper describes the optimisation and validation of an ultra performance liquid chromatography- tandem mass spectrometry (UPLC-MS/MS) method for the analysis of four pharmaceuticals (flubendazole, pipamperone, rabeprazole and domperidone) and one pesticide (propiconazole) in surface water. Sample preparation was reduced substantially as compared to a previously published high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method, thanks to the use of UPLC. In addition, internal standards could now be used for quantification instead of the standard addition method. Extraction was performed on a Speedisk phenyl solid-phase extraction tube. A Waters Acquity HSS T3 UPLC column (100 × 2.1 mm i.d.; 1.8-µm particles) was used for separation and an API 4000 triple quadrupole was used as a detector. Total run time was 8.59 minutes. Matrix effects were examined on different surface water samples. Limits of detection and quantification in surface water samples were between 100 and 500 pg/l. Validation was performed on surface water. The method showed good precision (<15%) and accuracy (85–120%). This method is less time-consuming and labour-intensive than a previously published HPLC-procedure without compromising validation parameters. [ABSTRACT FROM AUTHOR]