Fast ultrasound‐assisted extraction combined with LC–MS/MS of perfluorinated compounds in manure

A fast analytical method for the determination of perfluorinated compounds in poultry manure by LC–MS/MS was developed. The extraction was carried out by ultrasound‐assisted extraction of 1 g of sample, during 2 × 15 min using low volume (5.5 mL) of a mixture of methanol and acetonitrile. An efficient extraction of perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, and perfluoroalkyl sulfonamides from poultry manure was obtained with recoveries higher than 81%. The cleanup of extracts was carried out by dispersive SPE. The validation of the proposed method showed the suitability of this procedure to determine perfluorinated compounds in poultry manure with detection limits in the range of 0.44–2.12 ng/g, depending on the target compound. In comparison with previously published methods, the miniaturization of the sample preparation method with ultrasound‐assisted extraction together with the use of a core‐shell column permit a lower consumption of organic solvents and a fast analysis of perfluorinated compounds. Manure samples obtained from Spanish commercial farms were analyzed and low perfluorinated compounds levels were found, which may be originated by dietary or environmental exposure. The highest concentrations measured corresponded to the perfluoroalkyl sulfonates, which varied from 8.2 to 35.9 ng/g.     

同位素稀释三重串联四级杆质谱法测定鱼组织中24种多环芳烃

采用气相色谱-三重串联四级杆质谱联用技术测定了鱼组织中24种多环芳烃(PAHs).将冻干鱼组织样品加入同位素内标后,用加速溶剂萃取法(ASE)进行提取,提取液采用凝胶排阻色谱(GPC)和固相萃取(SPE)联用进行净化.采用二氯甲烷为提取溶剂,100℃下提取,以二氯甲烷作为GPC的流动相,在3.5 mL/min流速下,收...     

GC–MS/MS method for the determination and pharmacokinetic analysis of borneol and muscone in rat after the intravenous administration of Xingnaojing injection

A simple and sensitive gas chromatography with tandem mass spectrometry method was developed and validated for the simultaneous determination of borneol and muscone in rat plasma. The analytes and internal standard, naphthalene, were extracted using a convenient one‐step liquid–liquid extraction method with ethyl acetate. The chromatographic separation was realized on a HP‐5MS capillary column and detected in multiple reaction monitoring mode. Excellent linearity (R ² ≥ 0.996) was shown over 10.0–5000 ng/mL for borneol and 2.5–250 ng/mL for muscone. The lower limit of quantitation was 10 and 2.5 ng/mL for borneol and muscone, respectively. The intra‐ and interday precisions were less than 7.52%, and the accuracy values were between  −8.03 and 14.52%. The extraction recovery, matrix effect, and stability were sufficient to meet the Food and Drug Administration criteria. Meanwhile, the assay was successfully applied to the preclinical pharmacokinetic study of borneol and muscone following intravenous administration of Xingnaojing injection, a modern Chinese herbal medicine preparation.     

Analysis of emerging organic contaminants in poultry manure by gas chromatography–tandem mass spectrometry

A multiresidue method was developed for the determination of 19 emerging organic contaminants (pharmaceutical drugs, personal care products, and bisphenol A) in poultry manure. Lyophilized samples of manure were extracted by ultrasound‐assisted matrix solid‐phase dispersion and the extracts were analyzed by gas chromatography with tandem mass spectrometry after derivatization. Analysis of spiked poultry manure samples, at levels ranging from 25 to 150 ng/g, gave satisfactory recovery results for all the compounds, with values from 67 to 106%. The developed procedure provided detection limits that ranged from 0.9 to 2.2 ng/g. Finally, the validated method was applied to poultry manure samples collected from 23 poultry farms in Spain. Salicylic acid was found in most of the samples analyzed at levels up to 2501 ng/g, whereas, methyl paraben, orthophenylphenol, ibuprofen, paracetamol, and carbamazepine were detected at levels up to 250 ng/g. Composting of manure showed an important decrease in the levels of the detected contaminants.     

Simultaneous determination of pyrifluquinazon and its main metabolite in fruits and vegetables by using QuEChERS–HPLC–MS/MS

A rapid, reliable, and sensitive method is reported for the simultaneous analysis of pyrifluquinazon and its main metabolite NNI‐0101‐1H in fruits (strawberry and cherry) and vegetables (cucumber and tomato) using high‐performance liquid chromatography coupled with tandem mass spectrometry. A modified, quick, easy, cheap, effective, rugged, and safe procedure was used for the sample pre‐preparation. The target analytes were extracted with acetonitrile and then cleaned up using dispersive solid‐phase extraction procedure with primary secondary amine. Sample analysis was performed using electrospray ionization in positive mode. Good linearities with the correlation coefficients higher than 0.9991 were obtained in the range of 1–1000 μg/L under the optimized conditions. The average recoveries of the pyrifluquinazon and NNI‐0101‐1H were in the range of 71.4–106.0% with the relative standard deviations 1.8–11.8% in all matrices at three spiked levels (10, 100, and 1000 μg/kg). The limit of quantification 10 μg/kg was set as the lowest spiked level. The developed method is reliable and effective for the routine monitoring of pyrifluquinazon and its metabolite NNI‐0101‐1H in fruits and vegetables to ensure food safety.     

Analysis of polybrominated diphenyl ethers in sewage sludge by matrix solid‐phase dispersion and isotope dilution GC–MS

A method for the determination of 14 polybrominated diphenyl ethers (PBDEs) in sludge from wastewater treatment plants is presented. PBDEs were extracted by matrix solid‐phase dispersion assisted by sonication and determined by isotope dilution gas chromatography with electron impact mass spectrometric detection in the selected ion monitoring mode, using labelled ¹³C‐PBDEs as internal standards. The limits of detection and quantification for the tri‐ to hepta‐BDEs were in the range of 0.05 to 0.5 ng/g dry weight and 0.15 to 1.8 ng/g dry weight, respectively, and 1.6 ng/g dry weight and 5.6 ng/g dry weight for deca‐BDE‐209. The proposed analytical method was applied to determine PBDE levels in sewage sludge samples collected from 19 water treatment plants located in the province of Madrid (Spain). In all of the examined samples, BDE‐100 and BDE‐154 were the main compounds found with a mean concentration of 3.9 and 2.0 ng/g, respectively. PBDEs were detected in all of the samples, and their total concentrations not considering BDE‐209 were between 3.9 and 23.0 ng/g dry weight. The dominant PBDE congener in sewage sludge was BDE‐209, which constituted 38.7 to 97.3% of the total, and showed concentration levels ranging from 8.1 to 717.2 ng/g dry weight.     

GC–MS/MS method for the quantification of α‐cedrene in rat plasma and its pharmacokinetic application

α‐Cedrene is a pharmacologically active ingredient isolated from the essential oil of cedar. A selective and sensitive GC–MS/MS method was developed for the quantification of α‐cedrene in rat plasma for the first time. α‐Cedrene was extracted from rat plasma using ethyl acetate at neutral pH. The analytes were determined in selective reaction monitoring mode using MS/MS: m/z 204.3→119.0 for α‐cedrene and m/z 146.0→111.0 for 1,4‐dichlorobenzene (internal standard). The standard curve was linear (r² ≥ 0.995) over the concentration ranges of 5–800 ng/mL. The lower limit of quantification was 5 ng/mL using 50 μL of rat plasma. The coefficient of variation and relative error for intra‐ and interassays at four quality control levels were 3.1–13.9% and ?4.0–2.6%, respectively. The stability of processing (freeze–thaw, long‐term storage at ?80°C, and short‐term storage at room temperature) and chromatography (reinjection) was shown to be of insignificant effect. The present method was applied successfully to the pharmacokinetic study of α‐cedrene after its intravenous (10 mg/kg) and oral (25 mg/kg) administration in male Sprague‐Dawley rats.     

Development and validation of an analytical method for multiresidue determination of pesticides in lettuce using QuEChERS–UHPLC–MS/MS

A new analytical method for multiresidue determination of 16 multiclass pesticides in lettuce was developed using ultra‐high performance liquid chromatography with tandem mass spectrometry with a triple quadrupole mass analyzer and positive mode electrospray ionization, using a previously optimized quick, easy, cheap, effective, rugged, and safe method for sample preparation. Validation studies, according to document SANTE/11945/2015, demonstrated that the developed method is selective, accurate, and precise, providing recoveries of 70–120%, relative standard deviations ≤20% and quantification limits from 3 μg/kg. The method was compared with one based on high‐performance liquid chromatography with tandem mass spectrometry, in terms of chromatographic performance, detectability and matrix effect for five varieties of lettuce. The new method provided a reduction in the time for the chromatographic analysis of 50%, from 30 to 15 min, using a lower mobile phase flow rate (0.147 mL/min), which reduced the consumption of mobile phase by 25%, and injection of smaller amounts of sample (1.7 μL). Lower limits of quantification were obtained for almost all pesticides studied for green‐leaf lettuce. However, in relation to the matrix effect, four of the five types of lettuce studied presented higher matrix effects.     

Rapid determination of hexavalent chromium in textiles by a novel ammonium pyrrolidine dithiocarbamate derivatization combined with UHPLC–MS/MS

Hexavalent chromium is mainly determined by traditional spectrophotometry, atomic absorption spectrometry, and ion chromatography methods. In the present work, a reliable ultra high performance liquid chromatography with tandem mass spectrometry method was firstly developed for the determination of hexavalent chromium in textiles. The sample was extracted by acetic acid/sodium acetate buffer solution and followed by derivatization with ammonium pyrrolidine dithiocarbamate. The resulting derivative product was extracted by ethyl acetate, separated on a C18 column, and detected through electrospray ionization source in the positive mode with multiple reaction monitoring conditions. The derivatization reaction conditions were investigated and optimized. The developed method was validated in terms of the sensitivity, linearity range, matrix effects, recovery, accuracy, intra‐ and interday precision. Results showed that the calibration curves of pure solvent and matrix were linear over the selected concentration ranges of 0.1–20.0 μg/L. The achieved instrument and method limit of quantification were 0.1 and 40.0 μg/kg, respectively. Recoveries were calculated at three spiked concentrations and the values were between 92.2 and 103% with relative standard deviation values of 2.7–4.9% for intra‐day precision and 6.1% for inter‐day precision. Successful analysis of hexavalent chromium in practical textiles indicated that there was hexavalent chromium contamination in textiles.     

Simultaneous determination of 29 pharmaceuticals in fish muscle and plasma by ultrasonic extraction followed by SPE–UHPLC–MS/MS

A confirmatory method for the simultaneous detection of 29 pharmaceuticals in fish muscle and plasma was developed by using solid‐phase extraction combined with ultra‐high performance liquid chromatography and tandem mass spectrometry. Fish samples were extracted with methanol and enriched using Oasis HLB solid‐phase extraction columns in one step. Twenty‐nine target pharmaceuticals were quantified by the internal standard method and the calibration curves showed good linearity in a wide range with determination coefficients of greater than 0.913. The detection limits of the pharmaceuticals ranged from 0.01 to 2.00 μg/kg (μg/L). The applicability of the method was checked by precision and recovery experiments. The average recoveries of the 29 pharmaceuticals were between 61 and 111%, and all the relative standard deviations were below 25%. Our reported method has been demonstrated to be sensitive, convenient, rapid, and reliable for the simultaneous determination of 29 pharmaceuticals in fish muscle and plasma. Real sample determination showed that 25 and 9 of the 29 compounds were detected in fish muscle and plasma, respectively.     

Determination of 19 sulfonamides residues in pork samples by combining QuEChERS with dispersive liquid–liquid microextraction followed by UHPLC–MS/MS

A new simple and rapid pretreatment method for simultaneous determination of 19 sulfonamides in pork samples was developed through combining the QuEChERS method with dispersive liquid–liquid microextraction followed by ultra‐high performance liquid chromatography with tandem mass spectrometry. The sample preparation involves extraction/partitioning with QuEChERS method followed by dispersive liquid–liquid microextraction using tetrachloroethane as extractive solvent and the acetonitrile extract as dispersive solvent that obtained by QuEChERS. The enriched tetrachloroethane organic phase by dispersive liquid–liquid microextraction was evaporated, reconstituted with 100 μL acetonitrile/water (1:9 v/v) and injected into an ultra‐high performance liquid chromatography with a mobile phase composed of acetonitrile and 0.1% v/v formic acid under gradient elution and separated using a BHE C₁₈ column. Various parameters affecting the extraction efficiency were investigated. Matrix‐matched calibration curves were established. Good linear relationships were obtained for all analytes in a range of 2.0–100 μg/kg and the limits of detection were 0.04–0.49 μg/kg. Average recoveries at three spiking levels were in the range of 78.3–106.1% with relative standard deviations less than 12.7% (n = 6). The developed method was successfully applied to determine sulfonamide residues in pork samples.     

Development of microextraction techniques in combination with GC–MS/MS for the determination of mycotoxins and metabolites in human urine

Simple and highly efficient sample preparation procedures, namely, dispersive liquid–liquid microextraction and salting‐out liquid–liquid extraction for the analysis of ten Fusarium mycotoxins and metabolites in human urine were compared. Various parameters affecting extraction efficiency were carefully evaluated. Under optimal extraction conditions, salting‐out liquid–liquid extraction showed a better accuracy (84–96%) and precision (<14%) than dispersive liquid–liquid microextraction. Hence, a multibiomarker method based on salting‐out liquid–liquid extraction followed by gas chromatography with tandem mass spectrometry was proposed. Satisfactory results in terms of validation were achieved. The method resulted in low limits of detection and quantitation within the range of 0.12–4 and 0.25–8 μg/L, respectively. The method accuracy and precision were evaluated at three spiking levels (8, 25 and 100 μg/L) and the recoveries were in a range from 70 to 120% with relative standard deviations lower than 15%. Matrix effect was evaluated and matrix‐matched calibrations were used for quantitation purpose. The developed method was applied in 12 human urine samples as a pilot study before and after sample treatment with β‐glucuronidase before the analysis to quantify the mycotoxin conjugates. Total deoxynivalenol (free + conjugated) was found in 83% of samples at an average concentration in positive samples of 31.6 μg/L.     

Simultaneous determination of trace migration of phthalate esters in honey and royal jelly by GC–MS

A simple, rapid, and reliable liquid–liquid extraction coupled to GC–MS method was developed and validated for the quantification of 22 phthalate esters (PAEs) in honey and royal jelly. Instrument parameters for GC–MS were tested to obtain the satisfactory separation between 22 PAEs with high sensitivity. The extraction procedure was optimized in order to achieve the best recovery. The following criteria were used to validate the developed method: linearity, LOD, lower LOQ, precision, accuracy, matrix effect and carry‐over. Correlation coefficients were >0.999 by applying the linear regression model based on the least‐squares method with a weighting factor (1/x). The intra‐ and interday precision were within 12.7% in terms of RSD, and the accuracy was within ?11.8% in terms of relative error. The mean extraction recoveries ranged between 80.1 and 110.9% for honey and royal jelly. No significant matrix effect and carry‐over for PAEs were observed for the analysis of honey and royal jelly samples. A total of 20 real samples were analyzed for a mini‐survey using the developed method. Seven PAEs in honey samples and five PAEs in royal jelly samples were found, indicating potential contamination with several PAEs.     

Rapid determination of bisphenol A in drinking water using dispersive liquid‐phase microextraction with in situ derivatization prior to GC‐MS

This paper described a novel approach for the determination of bisphenol A by dispersive liquid‐phase microextraction with in situ acetylation prior to GC‐MS. In this derivatization/extraction method, 500 μL acetone (disperser solvent) containing 30.0 μL chlorobenzene (extraction solvent) and 30.0 μL acetic anhydride (derivatization reagent) was rapidly injected into 5.00 mL aqueous sample containing bisphenol A and K₂CO₃ (0.5% w/v). Within a few seconds the analyte was derivatized and extracted at the same time. After centrifugation, 1.0 μL of sedimented phase containing enriched analyte was determined by GC‐MS. Some important parameters, such as type and volume of extraction and disperser solvent, volume of acetic anhydride, derivatization and extraction time, amount of K₂CO₃, and salt addition were studied and optimized. Under the optimum conditions, the LOD and the LOQ were 0.01, 0.1 μg/L, respectively. The experimental results indicated that there was linearity over the range 0.1–50 μg/L with coefficient of correlation 0.9997, and good reproducibility with RSD 3.8% (n = 5). The proposed method has been applied for the analysis of drinking water samples, and satisfactory results were achieved.     

Elimination of Matrix Interferences in GC‐MS Analysis of Pesticides by Entropy Minimization

Gas chromatography‐mass spectrometry (GC‐MS ) is an important analytical technique for the analysis of organophosphorus pesticides in food products. Because of the complex matrices of food products, multiple preprocessing steps are required prior to performing the GC‐MS analysis. Despite that, it is difficult to totally eliminate the interference of complex matrix background. In this work, we introduce an entropy minimization technique that can eliminate the need for comprehensive preprocessing steps to detect organophosphorus pesticides in a fortified orange juice sample. The pure mass spectra and extracted‐ion chromatograms of the pesticides were extracted and reconstructed. The results achieved higher National Institute of Standard and Technology (NIST ) match scores in comparison to the conventional background subtraction technique. Taken together, the entropy minimization technique is capable of providing rapid qualitative and quantitative analyses of complex GC‐MS data. This technique is expected to have great potential for natural products and food analysis applications.     

Liquid‐phase microextraction by solidification of floating organic microdrop and GC‐MS detection of trihalomethanes in drinking water

A simple and sensitive methodology based on liquid‐phase microextraction (LPME) followed by GC‐MS, was developed for the determination of trihalomethanes (THMs) in drinking water. A microdrop of organic solvent was floated on the surface of the aqueous sample and it was agitated for a desired time. Then, the sample vial was cooled by inserting it into an ice bath for 4 min. The solidified solvent was transferred into a suitable vial and immediately melted. The extract was directly injected into the GC. Microextraction efficiency factors were investigated and optimized: 7 μL 1‐undecanol microdrop exposed for 15 min floated on the surface of a 10.0 mL aqueous sample with the temperature of 60°C containing 3 M of NaCl and stirred at 750 rpm. Under the selected conditions, enrichment factors (EFs) up to 482‐fold, LOD of 0.03–0.08 μg/L (S/N = 3) and dynamic linear ranges of 0.10–100 μg/L were obtained. A reasonable repeatability (RSD < 8.6%, n = 8) with satisfactory linearity (r² ? 0.9947) of results illustrated a good performance of the present method. The protocol proved to be rapid, cost‐effective, and is a green procedure for the screening purposes.     

Screening for inherited metabolic diseases using gas chromatography–tandem mass spectrometry (GC–MS/MS) in Sichuan,China

The aim of this study was to retrospectively diagnose and confirm inherited metabolic diseases (IMD), from a small population of IMD high‐risk patients, with the aid of gas chromatography–tandem mass spectrometry (GC–MS/MS), technologies yet to be popularized in Sichuan, China. Using GC–MS/MS coupled with clinical diagnosis, we retrospectively analyzed samples of dried blood spots and urine specimen from 183 IMD high‐risk infant patients, who visited the West China Second Hospital of Sichuan University between June 2013 and October 2015. Four out of 183 IMD high‐risk infant patients were finally diagnosed to be IMD positive, among which two patients were identified with phenylketonuria, one with maple syrup urine disease, and 1 with methylmalonic academia. Restrictive diets and other symptomatic treatments were employed to treat the confirmed infant patients whose conditions are still under tracking and there are zero cases of death so far. GC–MS/MS was found to be an efficient and reliable way to detect IMD. It is necessary to apply GC–MS/MS, in addition to other clinical approaches, for diagnosing candidate IMD patients so that the confirmed patients can get medical intervention and timely treatment.     

Simultaneous determination of 106 pesticides in nuts by LC–MS/MS using freeze‐out combined with dispersive solid‐phase extraction purification

As a result of the low water content and high fat matrices in nuts, it is very difficult to simultaneously determine multi‐pesticides in trace levels. Here, a sample pretreatment method was developed in which, microwave‐assisted solvent extraction was firstly used to extract pesticides, and then a two‐step cleanup method was conducted combining freeze‐out with dispersive solid‐phase extraction to remove the lipidic matrix. By this way, 106 pesticides were simultaneously determined in the complicated nut sample by using an ultra‐high pressure liquid chromatography coupled with a tandem mass spectrometer. Average recoveries were 75.3–119.3% with relative standard deviations < 14% at three concentration levels. The limits of detection and quantification were in the ranges of 0.3–3.0 and 1.0–10.0 μg/kg, respectively. Furthermore, the method was successfully applied to the determination of pesticides in 180 commercial nut samples.     

Determination of multiple antibiotics in leafy vegetables using QuEChERS–UHPLC–MS/MS

A modified quick, easy, cheap, effective, rugged, and safe method was established for simultaneous extraction and cleanup of multiple antibiotics in leafy vegetables, and ultra‐high performance liquid chromatography with tandem mass spectrometry was used for analysis. Antibiotics in leafy vegetables were extracted with citric acid/sodium citrate in mixed solvents consisting of acetonitrile/methanol (85:15, v/v) from 10 g of vegetables. Octadecylsilyl and graphitized carbon black were used as dispersant adsorbents. This method was able to effectively extract all of the target antibiotics from leafy vegetables. The average recoveries of 20 antibiotics ranged from 57 to 91%. The limits of detection were 0.33–2.92 μg/kg. The developed method subsequently demonstrated its selectivity, sensitivity, and reliability for detecting multiple antibiotics in 15 samples. Antibiotic residues in vegetables have attracted great concern with respect to human health. It is recommended that standards should be established for antibiotic residues in vegetables to ensure food safety.     

GC‐MS of amaryllidaceous galanthamine‐type alkaloids

Galanthamine‐type alkaloids produced by plants of the Amaryllidaceae family are potent acetylcholinesterase inhibitors. One of them, galanthamine, has been marketed as a hydrobromide salt for the treatment of Alzheimer's disease. In the present work, gas chromatography with electron impact mass spectrometry (GC‐EIMS) fragmentation of 12 reference compounds isolated from various amaryllidaceous plants and identified by spectroscopic methods (1D and 2D nuclear magnetic resonance, circular dichroism, high‐resolution MS (HRMS) and EIMS) was studied by tandem mass spectrometry (GC‐MS/MS) and accurate mass measurements (GC‐HRMS). The studied compounds showed good peak shape and efficient GC separation with a GC‐MS fragmentation pattern similar to that obtained by direct insertion probe. With the exception of galanthamine‐N‐oxide and N‐formylnorgalanthamine, the galanthamine‐type compounds showed abundant [M]^+. and [M‐H]⁺ ions. A typical fragmentation pattern was also observed, depending on the substituents of the skeleton. Based on the fragmentation pathways of reference compounds, three other galanthamine‐type alkaloids, including 3‐O‐(2′‐butenoyl)sanguinine, which possesses a previously unelucidated structure, were identified in Leucojum aestivum ssp. pulchelum, a species endemic to the Balearic islands. GC‐MS can be successfully applied to Amaryllidaceae plant samples in the routine screening for potentially new or known bioactive molecules, chemotaxonomy, biodiversity and identification of impurities in pharmaceutical substances. Copyright © 2012 John Wiley & Sons, Ltd.