QuEChERS extraction method

Usui, K., Hayashizaki, Y., Hashiyada, M., and Funayama, M. (2012) Rapid drug extraction from human whole blood using a modified QuEChERS extraction method. Leg. Med., 14 (6), 286- 296. 

Kaufmann et al. developed a bipolarity extraction method based on principles similar to those of the QuEChERS technique. With the use of this isolation technique, polar and non-polar residues remained in the aqueous phase and underwent clean-up by SPE on a mixed-mode Oasis HLB cartridge. The residues were subsequently analyzed by UPLC-MS/MS. Extracts isolated using the bipolarity approach required a lengthy SPE procedure prior to analysis. Kaufmann stated that extracts produced at the end of the procedure contained less matrix components compared to QuEChERS. However, it can be concluded that... 

Filigenzi, M. S., Ehrke, N., Aston, L. S., and Poppenga, R. H. 2011. Evaluation of a rapid screening method for chemical contaminants of concern in four food-related matrices using QuEChERS extraction, UHPLC and high resolution mass spectrometry. FoodAddit. Contam., PartA 28 1324-1339. 

Recent trends in pesticide analysis in food aims for reduced sample pretreatments or simplified methodologies (as QuEChERS approaches), the use of online purification processes, the use of new adsorbents (such as molecular imprinted polymers (MIPs) and nanomaterials) for the extraction and clean-up processes, and focused on the development of large multiresidue methods, most of them based on LC-MS/ MS. In spite of the relevant role of LC-MS/MS, GC-MS-based methods still play an important role in pesticide analysis in food. Despite the development achieved in the immunochemical approaches, the need for multi-residue methods has supported the development and use of instrumental techniques. 

Lately, a method called QuEChERS - using acetonitrile as the extraction solvent and MgS04 and NaCl for salting out - was proposed. 

The QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) method allows the extraction of a wide variety of pesticides from polar and basic (methamidophos, acephate, omethoate, imazalil and thiabendazole) to less polar, such as pyrethrins. Samples of homogenized grape (lOg) are extracted with 10 mL of acetonitrile. After shaking for 1 min, 4 g of anhydrous MgS04 and 1 g of NaCl are added and mixed. One milliliter of the acetonitrile aliquot is transferred to a 1.5 mL vial... 

TABLE 9.7. Retention Times (RT) and Quantification Ions in the GC/MS-SIM Analysis of Pesticides in Grape Extract and Wine Coupled with the QuEChERS Method"... 

Selectivity of partitioning The addition of citrus buffering salts to elevate the pH of sour fruits has also dramatically reduced the amount of co-extractives in the raw extracts. This observation was also made during the development of the original QuEChERS method where the peaks of fatty acids as well as of maleic and fumaric acid in full-scan GC/MS became smaller as the pH of acidic samples... 

Anastassiades, M. Lehotay, S.J. Stajnbaher, D. Schenck, F. Fast and easy multiresidue method employing acetonitrile extraction/ partitioning and dispersive solid phase extraction for the determination of pesticide residues in produce. (QuEChERS method). J. AOACInt. 2003, 86, 412 31. 

Sampling, sample handling, and storage and sample preparation methods are extensively covered, and modern methods such as accelerated solvent extraction, solid-phase microextraction (SPME), QuEChERS, and microwave techniques are included. Instrumentation, the analysis of liquids and solids, and applications of NMR are discussed in detail. A section on hyphenated NMR techniques is included, along with an expanded section on MRI and advanced imaging. The IR instrumentation section is focused on FTIR instrumentation. Absorption, emission, and reflectance spectroscopy are discussed, as is ETIR microscopy. ATR has been expanded. Near-IR instrumentation and applications are presented, and the topic of chemometrics is introduced. Coverage of Raman spectroscopy includes resonance Raman, surface-enhanced Raman, and Raman microscopy. 

Despite the important advances in fast LC, food matrices are very complex, and although in general multi-residue methods with minimal sample manipulation are demanded, sample extraction and clean-up treatments must be carefully developed to also reduce the total analysis time. The most recently introduced sample treatment methodologies for pesticide residue analysis have also been addressed, with QuEChERS being the most popular one for its easy application and good results. However, other alternatives, such as online SPE or the use of more selective methods such as MIP, are also being applied for the analysis of pesticides. 

In order to evaluate the performance of the three selected methods, wheat blank samples spiked at 50 (Xg/kg were treated, applying the three procedures showing the obtained results. It can be observed that the best results were obtained when QuEChERS procedure was used, allowing the extraction of more than 80 compounds with suitable recoveries (70-120%) and relative standard deviation (RSD) lower than 20%. When the ultrasound method was applied, more than 80 compounds were extracted, but only 36 compounds, including all the mycotoxins and biopesticides assayed in this study, were quantitatively extracted, whereas this approach was not suitable for most of the selected pesticides. Finally, an intermediate situation was obtained when the procedure described by Mol et al. was applied. More than 50 compounds were extracted with recoveries ranging from 70% to 120% and RSD values lower than 20%. 

For analytical studies, sample preparation is necessary to determine the composition of phenolic compounds in these matrices. The most widely used extraction system is UAE, which is an inexpensive method since it involves the use of low organic solvent and requires short extraction times. Multi-analyte methods with minimal sample manipulation are demanded. However, vegetables and fruits are very complex matrices and hence sample extraction and clean-up treatments must be carefully developed to reduce manipulation and total analysis time. Therefore, QuEChERS could be a useful tool for this purpose in future applications. 

The extraction of milk samples was done by the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method [13], modified by adding disodium ethylene-diaminetetraacetate dihydrate (Na2-EDTA). Without any further cleanup, the extract was separated on HPTLC silica gel plates modified by Na2-EDTA. The development was performed with chloroform/methanol/ammonium hydroxide solution (25%), 60/35/5 (v/v/v), followed by fluorescence densitometry (ELD) at 366 nm/<400 nm... 

EN 15662 Determination of pesticide residues using GC-MS and/or LC-MS(/MS) following acetonitrile extraction/partitioning and cleanup by dispersive SPE—QuECHERS method. In European Committee for Standardization, Technical Committee CEN/TC 275, Food analysis—horizontal methods. Brussels European Committee for Standardization, 2008. 

On the other hand, the QuEChERS (quick, easy, cheap, effective, rugged, and safe) method, originally developed for pesticide analysis [23], has been also applied to the determination of multiclass veterinary drugs in different food commodities [24—27], The conventional QuEChERS strategy applies acetonitrile extraction, followed by removal of water and proteins by salting out with sodium chloride and magnesium sulphate. Afterwards, dispersive SPE (d—SPE) is usually applied. The QuEChERS approach has many advantages, as it is simple and quick, reduces the... 

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