Graphene as dispersive solidphase extraction materials for pesticides LC-MS/MS multi-residue analysis in leek, onion and garlic

Abstract

A multi-residue analytical method was validated for 24 representative pesticides residues in onion, garlic and leek. The method is based on modified QuEChERS sample preparation with a mixture of graphene, primary secondary amine (PSA), and graphitised carbon black (GCB) as reversed-dispersive solid-phase extraction (r-DSPE) material and LC-MS/MS. Graphene was first used as an r-DSPE clean-up sorbent in onion, garlic and leek. The results first show that the mixed sorbent of graphene, PSA and GCB has a remarkable ability to clean-up interfering substances in the r-DSPE procedure when compared with the mixture of PSA and GCB. Use of matrix-matched standards provided acceptable results for tested pesticides with overall average recoveries between 70.1% and 109.7% and consistent RSDs <15.6%. In any case, this method still meets the 1-10 μg kg(-1) detection limit needed for pesticide testing and may be used for qualitative screening applications in which any identified pesticides can be quantified and confirmed by a more intensive method that achieves >70% recovery.

Two-step dispersive-solid phase extraction strategy for pesticide multiresidue analysis in a chlorophyll-containing matrix by gas chromatography–tandem mass spectrometry

“…The QuEChERS procedure allows analysts to process a greater number of samples in a shorter period of time than with previously used methods. In the case of QuEChERS-based methods complicated analytical steps involved in traditional methods are omitted or replaced by more zirconium dioxide-based sorbents (Z-Sep, Z-Sep+, Z-Sep/C18) [5][6][7][8][9], ChloroFiltr [10], florisil [11], alumina neutral [12], nonfriable GCB (CarbonX) [7], graphene [13], multi-walled nanotubes [14], chitin, chitosan and diatomaceous earth [15]. For matrices of high complexity, a mixture of two or three different sorbents can be used to achieve sufficient cleanup of various kind of co-extractives without severely affecting pesticide recoveries [4][5][6][7][8][9][10][11][12][13][14]16].…”

Determination of Picoxystrobin Residues in Watermelon Field Trials by Rapid Resolution Liquid Chromatography Triple Quadrupole Mass Spectrometry: Dissipation Kinetics and Terminal Residues

“…Up to now, the residue of picoxystrobin has been concentrated in analytical methods in different matrices, including crops (Walorczyk et al 2015;Mercader et al 2012;Guan et al 2013;Hiemstra and Kok 2007;Cunha and Fernandes 2011), baby foods (Viñas et al 2009), fruits and vegetables (Lacina et al 2010;Guan et al 2014;Melo et al 2012;Campillo et al 2010), fruit juice (Liang et al 2013;You et al 2015), honeybees (Walorczyk and Gnusowski 2009), beer (Esteve-Turrillas et al 2010), and chrysanthemum (Xue et al 2015). In these studies, gas chromatography-mass spectrometry (GC-MS) was the most commonly used instrument (Bartlett et al 2002;Walorczyk et al 2015;Cunha and Fernandes 2011;Melo et al 2012;You et al 2015).…”

Salt-Assisted Graphene Oxide Dispersive Solid Phase Microextraction for Sensitive Detection of Malachite Green and Crystal Violet by HPLC

“…Therefore, it was widely used for sensing [31], extraction [32] or even signal application [33]. The adsorption capacity and dispersibility of GO made it a good sorbent material for DSPME [34][35][36]. However, the main associated problem is the difficulty in re-collection of GO from a well-dispersed solution even by high-speed centrifugation [37].…”