scholarly journals An Optimized Extraction Procedure for Determining Acaricide Residues in Foundation Sheets of Beeswax by Using Gas Chromatography-Mass Spectrometry

Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 804
Author(s):  
María Jesús Nozal ◽  
Edgar Imaz ◽  
José Luis Bernal ◽  
José Luis Nieto ◽  
Mariano Higes ◽  
...  

Pesticides can be found in beehives for several reasons, including contamination from surrounding cultivars; yet one of the most pertinent is related to the fact that beekeepers employ acaricides to control various types of mites, which may accumulate in beeswax due to their lipophilic nature. In the present study, foundation sheets of different origins, collected over a period of three years, were analyzed to detect the residues of seven acaricides (atrazine, chlorpyrifos, chlorfenvinphos, alpha-endosulfan, bromopropylate, coumaphos, tau-fluvalinate) by gas chromatography with mass spectrometric detection. An efficient sample treatment (recoveries between 90% and 108%) is proposed, involving solvent extraction with 1% acetic acid in acetonitrile mixture followed by dispersive solid-phase extraction (enhanced matrix removal lipid) and a polishing step. An evaluation was made of the analytical performance of the proposed method. It was shown to be selective, linear from a limit of quantification to 5000 µg/kg, precise (relative standard deviation values were below 6%), and with a goo sensitivity (limit of quantification ranging from 5 to 10 µg/kg). Finally, results showed that a large majority of the sheets analyzed (>90%) contained residues of at least one of these compounds. Coumaphos and tau-fluvalinate residues were the most common, with chlorpyrifos and chlorfenvinphos detected to a lesser extent.

2004 ◽  
Vol 87 (4) ◽  
pp. 1021-1027 ◽  
Author(s):  
Ana Gago-Martínez ◽  
María J Nogueiras ◽  
Sandra Rellán ◽  
Juan Prado ◽  
María F Alpendurada ◽  
...  

Abstract In this work, solid-phase microextraction (SPME) has been applied as an alternative for the selective extraction of 3 polybrominated diphenyl ethers (PBDEs), 2,2′,4,4′-tetrabromodiphenyl ether (PBDE-47); 2,2′,4,4′,5-pentabromodiphenyl ether (PBDE-99); and 2,2′,4,4′,6-pentabromodiphenyl ether (PBDE-100), and 2 alkylphenols, 4-tert-OP and 4-NP, prior to their analysis by gas chromatography/mass spectrometry (GC/MS). The advantages of this technique are mainly its simplicity, cost-effectiveness, and time-saving sample preparation, as well as being a solvent-free technique. With the aim of optimizing the conditions for an efficient extraction of the studied compounds, different fiber coatings and the main parameters affecting the extraction procedure have been evaluated. The results obtained showed a good linearity in the range of concentrations investigated, and adequate relative standard deviation values were found according to the range accepted for SPME. Recovery values were in the range of 78–108%, and good detection and quantitation limits at ppt levels were obtained for both methods, allowing the determination of the selected compounds in samples at trace levels. The results obtained clearly show the potential of SPME for efficient concentration of the target compounds and also demonstrate the reliability of this extraction technique for their GC/MS analysis.


2005 ◽  
Vol 88 (6) ◽  
pp. 1834-1839 ◽  
Author(s):  
Nicholas G Tsiropoulos ◽  
Konstantinos Liapis ◽  
Dimitrios T Likas ◽  
George E Miliadis

Abstract Analytical methodology was developed and validated for the determination of spiroxamine residues in grapes, must, and wine by gas chromatography/ion trap-mass spectrometry (GC/IT-MS). Two extraction procedures were used: the first involved grapes, must, and wine extraction with alkaline cyclohexane–dichloromethane (9 + 1, v/v) solution, and the second grape extraction with acetone, dichloromethane, and petroleum ether. In both procedures, the extract was centrifuged, evaporated to dryness, and reconstituted in cyclohexane or 2,2,4-trimethylpentane–toluene (9 + 1, v/v), respectively. Spiroxamine diastereomers A and B were determined by GC/IT-MS, and a matrix effect was observed in the case of grapes but not in must and wine. Recovery of spiroxamine from fortified samples at 0.02 to 5.0 mg/kg ranged from 78–102% for grapes and must, with relative standard deviation (RSD) <13%; for red and white wines, recoveries ranged from 90 to 101% with RSD <9%. The limit of quantification was 0.02 mg/kg for grapes, must, and wine or 0.10 mg/kg for grapes, depending on the extraction procedure used.


2012 ◽  
Vol 485 ◽  
pp. 68-71
Author(s):  
Na Wu ◽  
Yu Da Zhang ◽  
Wei Liu ◽  
Ping Yi ◽  
Ze Feng Wang ◽  
...  

A simple and effective extraction method based on solid-phase extraction (SPE) was developed to determine chlorothalonil, metalaxyl, triadimefon, dimetachlone, procymidone, flumetralin, oxadixyl and iprodione in Panax Notoginseng using gas chromatography-mass spectrometry with selected ion monitoring (GC/MS, SIM). The prepared samples were analysed with GC-MS in the selected ion monitoring mode (SIM) using one target and two or three qualitative ions for each analyte. In the method, hexane - dichloromethane(6:4,v/v)was selected to effectively extract the pesticides from the Panax Notoginseng samples. Solid-phase extraction was carried out using Supelclean ENVI-Carb/NH2 SPE Column with acetonitrile-toluene (3:1, v/v) as the eluted solvent. In the linear range of each pesticide, the correlation coefficient was R2≥0.99. The limit of detection ranged from 0.001 to 0.05 µg.mL-1, average recoveries ranged from 79.80% to 95.00%, with relative standard deviations between 1.96% and 4.32% for all 8 pesticides.They were readily achieved with this method for all tested pesticides.


2000 ◽  
Vol 83 (5) ◽  
pp. 1082-1086 ◽  
Author(s):  
Maurizio Guidotti

Abstract A method was developed for the selective determination of Se4+ in drinkable water by solid-phase microextraction (SPME) and gas chromatography/mass spectrometry (GC/MS). Se4+ was selectively derivatized to ethane, 1,1′-selenobis by reaction with sodium tetraethylborate, extracted by the SPME fiber, and determined by GC/MS. Both headspace (HS)–SPME and direct SPME were studied. The method requires only a few milliliters of sample and 20 min for completion. At 2.0 μg/L concentration, the relative standard deviation was 10.1% for HS–SPME and 9.1% for direct SPME. For HS–SPME, the theoretical detection limit was 81 ng/L and 166 ng/L for direct SPME. The recovery rate was 95%. The method was used to determine Se4+ in 10 tap water samples.


Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7143
Author(s):  
Tianao Mao ◽  
Haoyang Wang ◽  
Zheng Peng ◽  
Taotao Ni ◽  
Tianqi Jia ◽  
...  

A gas chromatography-mass spectrometry (GC/MS) method for the determination of hexabromocyclododecane (HBCD) in expanded polystyrene and extruded polystyrene foam (EPS/XPS) was developed. The EPS/XPS samples were ultrasonically extracted with acetone and the extracts were purified by filtration through a microporous membrane (0.22 μm) and solid-phase extraction. The samples were analyzed using a GC/MS using the selected ion monitoring mode. The ions 157, 319 and 401 were selected as the qualitative ions, while ion 239 was chosen as the quantitative ion. An HBCD standard working solution with a concentration range of 1.0–50.0 mg/L showed good linearity. The detection limit of HBCD was 0.5 mg/kg, meeting the LPC limit (<100 or 1000 mg/kg). Six laboratories were selected to verify the accuracy of the method, and 10 samples were tested. The interlaboratory relative standard deviation range was 3.68–9.80%. This method could play an important role in controlling HBCD contamination in EPS/XPS.


1996 ◽  
Vol 79 (6) ◽  
pp. 1428-1433 ◽  
Author(s):  
Thomas Heberer ◽  
Hans-Juergen Stan

Abstract A sensitive analytical method was developed for determining trace levels of dichlorprop, mecoprop, clofibric acid, and naphthylacetic acid in soil samples. The method applies extraction with acetone and aqueous acetic acid followed by solid-phase extraction as the first cleanup step. After target analytes are derivatized with pentafluorobenzyl bromide, they are determined by capillary gas chromatography (GC)/mass spectrometry with selectedion monitoring. Further cleanup of sample extract by gel permeation chromatography prevented the GC system from being contaminated with matrix compounds, although in most cases, it was not necessary. Limits of detection and quantitation as low as 0.1 and 1 ppb, respectively, were achieved. Recoveries of all analytes were &gt;90%, with relative standard deviations of &lt;10%.


2001 ◽  
Vol 84 (5) ◽  
pp. 1420-1430 ◽  
Author(s):  
François van Hoof ◽  
Peter van Wiele ◽  
Auguste Bruchet ◽  
Isabelle Schmitz ◽  
Ivana Bobeldiji ◽  
...  

Abstract As part of a project funded by the European Commission (EC) for the development and evaluation of multiresidue methods for analysis of drinking and related waters, 15 European laboratories evaluated a method using styrene–divinylbenzene copolymer solid-phase extraction followed by gas chromatography/mass spectrometry. The main aim of the study was to evaluate whether the method meets the requirements of EC Directive 98/83 in terms of accuracy, precision, and detection limit for 22 pesticides according to the following requirements: limit of detection, ≤0.025 μg/L; accuracy, expressed as recovery between 75 and 125%; and precision, expressed as repeatability relative standard deviation of the method of &lt;12.5% and as reproducibility relative standard deviation of the method of &lt;25%. Analyses for unknown concentrations were performed with fortified commercial bottled and tap waters. All laboratories were able to achieve detection limits of 0.01 μg/L for all pesticides except dimethoate and desisopropylatrazine (0.02 μg/L). The criteria for repeatability were met for all compounds except trifluralin, dimethoate, and lindane in bottled water and chlorpyrifos, dimethoate, and lindane in tap water. The criteria for reproducibility were met for all compounds except trifluralin, dimethoate, and lindane in bottled water and pendimethalin, chlorpyrifos, dimethoate, terbutryn, and lindane in tap water. In terms of accuracy, the method meets the requirements for all pesticides in both matrixes, except for lindane in bottled water and lindane and chlorpyrifos in tap water.


Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 445
Author(s):  
Steven Mascrez ◽  
Sabine Danthine ◽  
Giorgia Purcaro

Unlike other fields, the methods routinely applied for fats and oils are still tied to traditional, time- and solvent-consuming procedures, such as saponification, column chromatography and thin-layer chromatography. In this paper, microwave-assisted saponification followed by a lab-made solid-phase extraction was optimized for the characterization of either dialkyl ketones (DAK) or sterols or both simultaneously. The instrumental determination was performed by gas chromatography- flame ionization detector (GC-FID) for quantification and gas chromatography-mass spectrometry (GC-MS) for confirmation purposes. The proposed method showed good recoveries (>80%) and limit of quantification (0.04–0.07 μg/g for the 4 DAK and of 0.07 μg/g for α-cholestanol). Repeatabilities (n = 3) were below 15% for DAKs and generally lower than 6% for sterols. Accuracy on the entire sterol profile was confirmed in comparison to the International Olive Council reference method. The method was finally applied to real-world samples before and after chemical interesterification.


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