scholarly journals Modern Methods of Sample Preparation for the Analysis of Oxylipins in Biological Samples

Molecules ◽  
2019 ◽  
Vol 24 (8) ◽  
pp. 1639 ◽  
Author(s):  
Liakh ◽  
Pakiet ◽  
Sledzinski ◽  
Mika
Keyword(s):  
Mass Spectrometry ◽  
Sample Preparation ◽  
Biological Samples ◽  
Solid Phase ◽  
Biological Tissues ◽  
Gas Chromatography Mass Spectrometry ◽  
Liquid Liquid Extraction ◽  
Wide Range ◽  
Popular Subject ◽  
Technological Platforms

Oxylipins are potent lipid mediators derived from polyunsaturated fatty acids, which play important roles in various biological processes. Being important regulators and/or markers of a wide range of normal and pathological processes, oxylipins are becoming a popular subject of research; however, the low stability and often very low concentration of oxylipins in samples are a significant challenge for authors and continuous improvement is required in both the extraction and analysis techniques. In recent years, the study of oxylipins has been directly related to the development of new technological platforms based on mass spectrometry (LC–MS/MS and gas chromatography–mass spectrometry (GC–MS)/MS), as well as the improvement in methods for the extraction of oxylipins from biological samples. In this review, we systematize and compare information on sample preparation procedures, including solid-phase extraction, liquid–liquid extraction from different biological tissues.

scholarly journals Validation of a Fast and Easy Method for the Determination of Residues from 229 Pesticides in Fruits and Vegetables Using Gas and Liquid Chromatography and Mass Spectrometric Detection

2005 ◽  
Vol 88 (2) ◽  
pp. 595-614 ◽  
Author(s):  
Steven J Lehotay ◽  
André de Kok ◽  
Maurice Hiemstra ◽  
Peter van Bodegraven
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Fruits And Vegetables ◽  
Ion Trap ◽  
Solid Phase ◽  
Gas Chromatography Mass Spectrometry ◽  
Easy Method ◽  
Wide Range ◽  
Dispersive Spe

Abstract Validation experiments were conducted of a simple, fast, and inexpensive method for the determination of 229 pesticides fortified at 10–100 ng/g in lettuce and orange matrixes. The method is known as the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method for pesticide residues in foods. The procedure involved the extraction of a 15 g sample with 15 mL acetonitrile, followed by a liquid–liquid partitioning step performed by adding 6 g anhydrous MgSO4 plus 1.5 g NaCl. After centrifugation, the extract was decanted into a tube containing 300 mg primary secondary amine (PSA) sorbent plus 1.8 g anhydrous MgSO4, which constituted a cleanup procedure called dispersive solid-phase extraction (dispersive SPE). After a second shaking and centrifugation step, the acetonitrile extract was transferred to autosampler vials for concurrent analysis by gas chromatography/mass spectrometry with an ion trap instrument and liquid chromatography/tandem mass spectrometry with a triple quadrupole instrument using electrospray ionization. Each analytical method was designed to analyze 144 pesticides, with 59 targeted by both instruments. Recoveries for all but 11 of the analytes in at least one of the matrixes were between 70–120% (90–110% for 206 pesticides), and repeatabilities typically <10% were achieved for a wide range of fortified pesticides, including methamidophos, spinosad, imidacloprid, and imazalil. Dispersive SPE with PSA retained carboxylic acids (e.g., daminozide), and <50% recoveries were obtained for asulam, pyridate, dicofol, thiram, and chlorothalonil. Many actual samples and proficiency test samples were analyzed by the method, and the results compared favorably with those from traditional methods.

scholarly journals Determination of Pesticides in Composite Dietary Samples by Gas Chromatography/Mass Spectrometry in the Selected Ion Monitoring Mode by Using a Temperature-Programmable Large Volume Injector with Preseparation Column

2001 ◽  
Vol 84 (3) ◽  
pp. 891-900 ◽  
Author(s):  
Laura Rosenblum ◽  
Thomas Hieber ◽  
Jeffrey Morgan
Keyword(s):  
Mass Spectrometry ◽  
Sample Preparation ◽  
Diatomaceous Earth ◽  
Gas Chromatography Mass Spectrometry ◽  
Selected Ion Monitoring ◽  
Residue Detection ◽  
Relative Standard ◽  
Wide Range ◽  
Mode Method

Abstract Use of a temperature-programmable preseparation column in the gas chromatographic (GC) injection port permits determination of a wide range of semi-volatile pesticides including organochlorines, organophosphates, triazines, and anilines in fatty composite dietary samples while reducing sample preparation time and solvent consumption. Dietary samples are mixed with diatomaceous earth and are Soxhlet-extracted with an azeotropic solution of hexane and acetone. Sample preparation uses liquid–liquid partitioning over diatomaceous earth followed by normal phase chromatography over partially deactivated alumina. The final cleanup step occurs in a preseparation column in the GC injector, which is able to perform splitless transfer of the analytes to the analytical column and purge 99% of the high molecular weight residue. Detection is performed by GC/mass spectrometry (MS) in the selected ion monitoring mode. Method detection limits were at or below 2 ng/g for 24 of 35 pesticides studied, with recovery between 70 and 125% for 27 pesticides in samples fortified at 10 ng/g. Recovery was not dependent on fat content when measured in laboratory fortified samples containing 1, 5, and 10% fat by weight. Precision over multiple injections was acceptable, with a relative standard deviation of 2.6–15% for 25 analytes.

scholarly journals An Effective and Efficient Sample Preparation Method for 2-Methyl-Isoborneol and Geosmin in Fish and Their Analysis by Gas Chromatography-Mass Spectrometry

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Liang-liang Tian ◽  
Feng Han ◽  
Essy Kouadio Fodjo ◽  
Wenlei Zhai ◽  
Xuan-Yun Huang ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Sample Preparation ◽  
Large Scale ◽  
Solid Phase ◽  
Gas Chromatography Mass Spectrometry ◽  
Chromatography Mass Spectrometry ◽  
Ms Analysis ◽  
Fish Samples

The intensive aquaculture strategy and recirculating aquaculture system often lead to the production of off-flavor compounds such as 2-methyl-isoborneol (2-MIB) and Geosmin (GSM). The regular purge and trap extraction followed by analysis with gas chromatography-mass spectrometry (GC-MS) usually involve a complicated assembly of facilities, more working space, long sample preparation time, and headspace solid-phase microextraction (SPME). In this work, a method with easier sample preparation, fewer and simplified facilities, and without SPME on GC-MS analysis is developed for the determination of 2-MIB and GSM in fish samples. Unlike previous methods, solvent extract from samples, QuEChERS-based cleanup, and solid-phase extraction for concentration are applied. The LOD (S/N > 3) and LOQ (S/N > 10) of this method were validated at 0.6 μg/kg and 1.0 μg/kg for both 2-MIB and GSM, which are under the sensory limit (1 μg/kg). Application of this method for incurred fish samples demonstrated acceptable analytical performance. This method is suitable for large-scale determination of 2-MIB and GSM in fish samples, owing to the use of simple facility and easy-to-operate procedure, rapid sample preparation, and shorter time for GC-MS analysis without SPME.

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