buffered method gave better results for screening of those pesticides. Also, due to the recent shortage in acetonitrile (MeCN), ethyl acetate (EtOAc) was evaluated as a substitute solvent in the acetate-buffered QuEChERS version, but it generally led to less clean extracts and lower recoveries of pymetrozine, thi-

Different QuEChERS and dispersive solid-phase extract (d-SPE) sorbent compositions were evaluated in terms of recovery and matrix effects. The best results were obtained with citrate-buffered version QuEChERS and a cleanup step, with 150 mg of MgSO4, 50 mg of primary secondary amine (PSA), 50 mg of C18, and 5 mg of carbon. 13. Why is the original QuEChERS method non-buffered? The original non-buffered QuEChERS method was developed for an analysis of fewer pesticides. When the method was used for a larger pesticide screen, quite a few compounds demonstrated pH dependency. Therefore the buffered methods were introduced. 14. QuEChERS + 1% FA 102 4 104 5 101 5 2.4.5-T QuEChERS 92 6 99 6 85 3 QuEChERS + 1% FA 102 2 102 4 99 3 2.4.5-TP (Fenoprop) QuEChERS 96 3 99 3 91 2 QuEChERS + 1% FA 99 2 104 5 95 8 2.4.6-Trichlorophenol QuEChERS 95 10 104 4 105 5 QuEChERS + 1% FA 106 6 100 5 107 5 QuEChERS is a popular worldwide method for multi-residue analysis of pesticides in fruits and vegetables. This poster presents comparison data obtained using the original method from Anastassiades et. al. (2003) and the buffered QuEChERS methods. Sample is first extracted with acetonitrile, followed by a liquid- In this study, in order to monitor the quality of wolfberry in China, a method with acetate-buffered salt extraction and Sin-QuEChERS nanocolumn purification coupled with ultra performance liquid chromatography tandem mass spectrometry was developed for the determination of pesticide residues in wolfberry samples.

QuEChERS: Thinking out of the sample preparation box 11/23/2010. Sample Preparation AOAC Add Buffered Salts to Sample AOAC Sample Added to Buffered Salt: 0 10 20

The assessed method includes a sample preparation step based on the buffered QuEChERS approach. The TOF-MS fragmentation pattern of forchlorfenuron was studied at different fragmention voltages in the range of 120−270 V. Analyses were carried out under full-scan conditions by using the extracted ion chromatogram (XIC) of the m / z 248 ion

QuEChERS method for pesticide residue analysis requires only small quantities of solvent and is capable of generating recoveries of 70-120% with RSDs <5% for a wide range of compounds.

Buffered QuEChERS extraction tubes with foil packet containing 6 g of magnesium sulfate and 1.5 g of sodium acetate (AOAC Method 2007.01, for use with 15 g samples, Agilent Technologies p/n 5982-5755) buffered QuEChERS-based approach. Briefly, 10 mL of acidified (1% acetic acid) acetonitrile was added to 5 g (cereals/feed) or 10 g (fruit/vegetables) of homogenized sample. A mixture of salts was added and the centrifuge tube shaken and spun. The final acetonitrile extracts (0.5 or 1 g/mL in acetonitrile) were fortified with a mixture