MSPD as sample preparation method for determination of selected pesticide residues in apples

Abstract

A method for extraction and fast gas chromatographic (GC) determination of twenty pesticide residues of different volatility and polarity at ultratrace concentration level in apples is presented. Apples as representatives of non-fatty food were chosen as a matrix; they are also a common raw material for baby food production. Under fast GC conditions employing a mass spectrometric detector (MSD), several parameters of the MSPD procedure were optimised. Samples were homogenised with sorbent Florisil, pesticides were eluted with the optimised volume of etylacetate. After solvent evaporation to dryness, reconstitution of the rest to toluene follow and the final extract was injected. Recoveries obtained at three selected concentration levels were determined. The optimised procedure led to recoveries ≥ 90 % for the majority of the studied pesticides and the limits of quantification (LOQs) < 5 µg.kg -1 . Repeatability of gas chromatography-mass spectrometry (GC-MS) measurements of the matrix matched standards, expressed as the relative standard deviation (RSD [ %]), was in most cases acceptable for ultratrace concentration levels of pesticide residues.

Peel of Traditional Apple Varieties as a Great Source of Bioactive Compounds: Extraction by Micro-Matrix Solid-Phase Dispersion

“…To the best of our knowledge, the use of matrix solid-phase dispersion for the extraction of polyphenols from apple peel has not been considered at this moment. In studies dealing with apples, MSPD was mainly used for the determination of pesticides and mycotoxins in apples and apple-based products [28].Therefore, the aim of this study was the recovery of polyphenols from the peel of twelve traditional and eight commercial apple varieties grown in Croatia using MSPD extraction. The reason for using MSPD extraction for the recovery of polyphenols from apple peels is providing insight into new extraction possibilities for recovering polyphenols from apple peel and thus providing a perspective for scaling-up the process.…”

“…To the best of our knowledge, the use of matrix solid-phase dispersion for the extraction of polyphenols from apple peel has not been considered at this moment. In studies dealing with apples, MSPD was mainly used for the determination of pesticides and mycotoxins in apples and apple-based products [28].…”

Achievements and Challenges of Matrix Solid-Phase Dispersion Usage in the Extraction of Plants and Food Samples

“…The solid particles enable the disruption of plant and animal cells and the simultaneous absorption of the liquids together with the analytes. Among different sorbents, the most widely used are silica gel [18][19][20][21][22][23], octadecyl-modified silica gel [24][25][26][27][28], Florisil [29,30], and diatomaceous earth [31,32], which are sometimes mixed with other sorbents or drying agents [33][34][35]. However, apart from sorbents possessing active surfaces capable of interaction with the analytes, inert, nonporous materials are sometimes used, which can only crush the matrix, e.g., sand [36,37].…”

“…In the most widely used procedure, the solid mixture of the sample with the adsorbent is packed into an empty column, usually an empty SPE tube. The sample can be transferred from the mortar to the column as is, i.e., placed within two frits (or cotton plugs) without any other solid material [18][19][20][21]26,33,35,37,38,[44][45][46], or a portion of a sorbent, a drying material, or sand can be added below and/or above the sample [24,29,32,36,47,48]. The analytes are then eluted from the sorbent, which may be performed in one step or with successive portions of different solvents used for cleanup and elution.…”

“…Pesticides from the column were eluted with 60 mL of ethyl acetate. The eluate was collected and concentrated to dryness using a rotary vacuum evaporator, and the dry residue was dissolved in 1 mL of toluene [29]. While developing a method for determining pesticides in freeze-dried egg samples, dos Reis Souza et al tested Florisil and the C18 sorbent as a dispersing and cleaning material in MSPD.…”