A green ultrasonic-assisted liquid–liquid microextraction technique based on deep eutectic solvents for flame atomic absorption spectrometer determination of trace level of lead in tobacco and food samples

Deep Eutectic Solvents Application in Food Analysis

“…Currently, studies on the synthesis and application of HDESs for the extraction of a great variety of analytes from food matrices have expanded rapidly, which has led to an increase in the number of articles published in recent years. As can be seen in Table 2, several HDESs have been used for the extraction of both organic (phthalic acid esters [18,96,99], dyes [97,104,110,117], PAHs [17,85], sterols [98], pesticides [100,105,112,122,124,126,127], herbicides [102], insecticides [125], preservatives [101], pigments [86], antibiotics [87,103,108,114], fluorescent whitening agents [106], vitamins [107], mycotoxins [16], bisphenols [115], perfluoroalkyl substances [120] and terpenes [121]) and inorganic compounds (Co, Cd, Ni, As, V and Pb [109,111,113,116,118,119,123]) from aqueous phases (water [96,113,118,124], soft drinks…”

“…When it comes to solid samples such as dried fruits, cereals, onion, parsley or even dairy products (milk, yogurt, cheese, etc. ), they are usually digested with H 2 O 2 :HNO 3 (1:3, v/v) [109], although in some cases only HNO 3 is used [119,123], before the application of microextraction techniques. However, if a previous step such as QuEChERS (quick, easy, cheap, effective, rugged and safe) [112], is carried out before the extraction technique in dried fruits for example, it would only be necessary to grind and homogenize them.…”

“…In this sense, it is important to highlight that in certain cases, no additional solvents have been necessary to obtain a good dispersion of the HDES into the sample [18,86,[96][97][98]110]. Instead, the DLLME procedure has been assisted in different ways, including the vortex-assisted DLLME [86,97,99,100,104,106], ultrasound-assisted DLLME [16,85,87,101,113,116,123,124], air-assisted [109] and microwave-assisted DLLME [128]. However, other versions have also been used, such as DLLME based on the solidification of the floating organic drop (SFO) [18,115,122,126]; salting out-DLLME-back extraction or salt induced-homogenous liquid-liquid extraction-DLLME, in which a salt is added (e.g., NaCl, (NH 4 ) 2 SO 4 , Na 2 SO 4 or NH 4 Cl) to reduce the solubility of the analytes in water and to increase their distribution coefficients in the organic phase [108,114]; effervescence-assisted DLLME in which an effervescent reaction between a proton donor solvent (acetic acid, which has been previously mixed with HDES in a 3:1 (v/v) ratio) and an effervescent agent (sodium bicarbonate) is produced generating carbon dioxide that facilitates the dispersion of the extraction solvent (HDES, see Figure 2) [117]; or even the combination of DLLME with a previous extraction and clean-up stage, such as the QuEChERS method, in which the extracted supernatant was used as a dispersant in the following DLLME for further purification and preconcentration [112].…”

“…These separation techniques have been coupled to different detection systems, including UV [18,87,96,97,99,103,107,110,112,124,125], DAD [86,104,114], variable wavelength detectors [98], FD [17,101], MS [102,[120][121][122], MS/MS [85,115], FID [105,126,127] and ECD [100]. Other techniques have also been directly applied without a previous separation of the analytes, such as UV-Vis spectroscopy [16,117], fluorescence spectrometry [106] and AAS [109,111,113,116,118,119,123]. The combination of these techniques with the outstanding extraction performances shown by the synthesized HDESs has provided excellent sensitivity in all cases, with LODs in the low ppb level.…”

Application of thermal ultrasound‐assisted liquid–liquid micro‐extraction coupled with HPLC‐UV for rapid determination of synthetic phenolic antioxidants in edible oils

“…Micro-extraction techniques including LPME (liquid phase micro-extraction), SPME (solid phase micro-extraction), LLME (liquid-liquid micro-extraction), and DLLME (dispersive liquid-liquid micro-extraction) have been developed to measure food additives (Abedi et al, 2014;Dong & Wang, 2006;Xu et al, 2016). Optimizations have been done to improve the classical micro-extraction techniques including vortex assisted-DLLME (Faraji, 2019), ultrasound assisted-LPME (Memon et al, 2019), ultrasound assisted-DLLME (Ghasemzadeh-Mohammadi et al, 2012), air-assisted LLME (Farajzadeh et al, 2020), and microwave assisted-DLLME (Ghasemzadeh-Mohammadi et al, 2012). Rezaee et al (2006) introduced DLLME approach as efficient and rapid extraction for isolation and pre-concentration of some organic chemicals from aqueous matrix (Rezaee et al, 2006).…”