Hyphenated dispersive solid‐ and liquid‐phase microextraction technique based on a hydrophobic deep eutectic solvent: application for trace analysis of pesticides in fruit juices

Abstract

BACKGROUND Pesticides are extensively used worldwide to control plant pathogens and prevent agricultural product damage. However, they can pollute the environment and endanger human health. So far, a variety of sample preparation methods have been developed for the analysis of pesticide residues. RESULTS A hyphenated solid–liquid microextraction method based on a new adsorbent of magnetic graphene oxide functionalized by (3‐glycidyloxypropyl)trimethoxysilane and a deep eutectic solvent (choline chloride/4‐chlorophenol (1:2)) was developed for extraction/preconcentration of trace levels of pesticides. The sorbent was characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, and vibrating sample magnetometry. In‐syringe magnetic dispersive solid‐phase extraction in tandem with dispersive liquid–liquid microextraction followed by gas chromatography was applied for the analysis of the selected pesticides. The main parameters governing sample preparation efficiency, including adsorbent dosage, desorption conditions, pH, extraction time, deep eutectic solvent volume, and salt concentration, were investigated. The linear ranges were 0.024–500 μg L−1 with 0.9971–0.9999 linearity factor (R2). The limits of detection and quantification were 0.006–0.038 and 0.024–0.126 μg L−1, respectively. The relative standard deviations were 0.5–4.2% for intra‐day analysis and 2.7–4.6% for inter‐day analysis. Enrichment factors were in the range 210–540. CONCLUSIONS The method was successfully applied for the determination of malathion, heptachlor epoxide, endrin, dichlorodiphenyltrichloroethane, azinphos ethyl, cypermethrin, and deltamethrin in fruit juice samples (apple, pineapple, cherry, peach, and red and green grape juices) and the recoveries were within the range 71–115%. © 2020 Society of Chemical Industry

Deep Eutectic Solvents Application in Food Analysis

“…[60] As can be seen in the table, hydrophilic DESs have been used with very good performances for the preconcentration and extraction of an extensive diversity of analytes, including both organic compounds (i.e., antioxidants [25], polycyclic aromatic hydrocarbons (PAHs) [65], pesticides [53][54][55][56], amino acids [24], phenolic compounds and caffeine [10,35,38,52,60], flavonoids [29,32], anthocyanins [31,34,58], mycotoxins [33,37], aflatoxins [39], sex hormones [36], antibiotics [41], preservatives [67], organophosphorus pesticides (OPPs) [44,57], curcumin [22,25,40,45], polybrominated diphenyl ethers (PBDEs) [43], and organochlorine pesticides (OCPs) [43,72]) and metals (Cd, Zn, As, Sb, Fe, Cu, Se, Mn, Pb, Cr, Co, Hg and Al [11][12][13][14][15]23,[26][27][28]42,[46][47]…”

“…However, and as it has been previously mentioned, the miscibility of hydrophilic DESs with water generally limits their direct application to aqueous samples. For this reason, in these cases, a dispersing or emulsifying agent (generally tetrahydrofuran, THF, or acetonitrile, ACN) is usually added to obtain a cloudy solution, achieving the separation of the two liquid phases after a shaking and centrifugation step in DES-based DLLME procedures [12,40,42,[44][45][46][47][48][49][50][51][52]54,56]. Nonetheless, the addition of this solvent has negative consequences since it may reduce the environmental friendliness and increases the laboratory hazards.…”

“…However, they have also been separated and detected by UV-Vis spectrophotometry [14,22,38,40,45], atomic absorption spectroscopy (AAS) [11,23,47,68], slotted quartz tube-flame AAS [48,49], hydride generation AAS [12], graphite furnace AAS [15,26,42], ETAAS [13,27,46,50,51,71] and ICP-optical emission spectroscopy (OES) [28]. Gas chromatography (GC) coupled to electron capture detection (ECD) [54,72] or flame ionization detection (FID) [53,55,56] have also been used, although in a very reduced number of applications. Furthermore, in some cases, after performing the developed method, samples were injected into a GC-MS for better identification of the analytes.…”

Microextraction Techniques with Deep Eutectic Solvents

“…One of the approaches used to synthesize DESs is by mixing and heating two or more salts to form a homogenous solution. Typically, ambient temperature molten salts have been formed by mixing quaternary ammonium salts, a hydrogen bond acceptor (HBA) with metal salts [32,33]. Hence, four main different types of DES occur: I. quaternary salt with a metal chloride, II.…”

Vortex‐assisted dispersive liquid‐phase microextraction for the analysis of main active compounds from Zi‐Cao‐Cheng‐Qi decoction based on a hydrophobic deep eutectic solvent

“…DESs are easy to prepare, biodegradable, and hypotoxic making them have good potential to replace traditional organic solvents and even ILs [18,19]. Moreover, hydrophobic DES (hDES) has low solubility in water and a broad range of extraction ability for the target compounds with different polarities, which meets the conditions of being an extraction solvent for DLPME [20].…”