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BACKGROUND: A method has been developed based on a three–phase system, followed by dispersive liquid–liquid microextraction for the extraction of seven pesticides from soya milk prior to analysis by gas chromatography‐flame ionization detection. The base of this method is the different extraction capability of the components of soya milk according to each of the phases involved. In this procedure, a homogeneous solution consisting of soya milk and a water–miscible solvent (acetonitrile) is separated into two phases in the presence of Na2SO4 and the analytes are extracted into the produced acetonitrile droplets. The acetonitrile phase is mixed with a pre‐concentration solvent to perform the next microextraction procedure for further enrichment of the analytes. RESULTS: Limits of detection and quantification were reached in the ranges of 0.11–0.35 and 0.35–1.20 µg L−1, respectively. Enrichment factors and extraction recoveries were in the ranges of 562–933 and 56–93%, respectively. Relative standard deviations were ≤7% for intra– (n = 6) and inter–day (n = 5) precisions at two concentrations of 10 and 50 µg L−1 of each analyte. CONCLUSION: The proposed method was applied to the analysis of pesticides in soya milk samples at µg L−1 concentrations. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

In this work, an efficient magnetic sorbent has been prepared using the extract of Tanacetum leaves and used in magnetic dispersive solid phase extraction of Cu(II) and Pb(II) ions from high volume of milk samples performed in a narrow-bore tube. For this purpose, first, the sorbent was prepared by mixing Fe 3 O 4 magnetic nanoparticles and Tanacetum leaves extract. After precipitation of the milk proteins with trichloroacetic acid, the sedimented compounds were removed and the upper solution was filled into the narrow-bore tube. Then after that, the mg-level of the prepared sorbent was added. After doing the extraction procedure, the sorbent particles were removed from the tube in the presence of a magnetic field. The adsorbed analytes were desorbed by methanol and to achieve low detection limits, the eluent obtained from the first step was subjected to dispersive liquid-liquid microextraction. Finally, the enriched analytes were monitored by flame atomic absorption spectrometry. The important parameters affecting the method efficiency such as the sorbent amount, type and volume of elution and extraction solvents, vortex time, pH, and ionic strength were studied. Under optimized conditions, the proposed method showed linear ranges of 0.50–40 and 0.75–40 µg L−1 for Cu(II) and Pb(II) ions, respectively. Limits of detection were obtained 0.16 and 0.22 µg L−1 for Cu(II) and Pb(II), respectively. Enrichment factors of 182.5 and 173.7 and extraction recoveries of 95.8 % and 91.2 % were obtained for Cu(II) and Pb(II), respectively. The relative standard deviations (intra- and inter-day precisions) for 5 and 25 µg L−1 of each cation were between 2.4 % and 4.3 %. • Tanacetum extract was used for functionalisation of Fe 3 O 4. • The prepared MNPs was used for the extraction of heavy metals from milk. • The MDSPE was combined with a dispersive liquid-liquid microextraction procedure. • The method has low LODs and LOQs, high EFs and ERs. [ABSTRACT FROM AUTHOR]

A simple, green, rapid, and efficient ligandless dispersive liquid-liquid microextraction procedure based on solidification of a ternary deep eutectic solvent has been proposed for the extraction of trace amounts of Cd(II), Cu(II), and Pb(II) ions in milk samples prior to their determination by flame atomic absorption spectrometry. Initially, a suitable mole ratio of sorbitol, menthol, and mandelic acid are mixed in a test tube, and after heating, a deep eutectic solvent with low density compared to water is formed. The synthesized solvent is used as a chelating agent and an extraction solvent in the extraction of some heavy metal ions from milk samples. The influence of several effective parameters on the responses and extraction recoveries of the analytes was investigated. Under the optimum experimental conditions, the linear ranges were in the ranges of 1.0–40 μg L−1 for Cd(II) and Pb(II), and 1.0–25 μg L−1 for Cu(II). The obtained relative standard deviations (n = 6, C = 2.5 μg L−1 of each cation) and detection limits were in the ranges of 3.4–4.1% and 0.38–0.42 μg L−1, respectively. Finally, the developed method was successfully applied for the determination of Cd(II), Cu(II), and Pb(II) ions in different milk samples. Image 1 • An efficient ligandless DLLME method using a synthesized ternary DES is proposed for the extraction and preconcentration of Cd(II), Cu(II), and Pb(II) ions at trace levels from milk samples. • A few microliters of the synthesized DES was used simultaneously as a complexing agent and an extraction solvent, therefore, the extraction was performed without using any organic solvent. • This study is the first report on the application of the present method for the extraction of heavy metals in milk samples. • The proposed method offers numerous advantages, such as simplicity, ease of operation, and low cost. • The developed method was used for the determination of the analytes in different milk samples. [ABSTRACT FROM AUTHOR]