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In this work, walnut green husk has been used as a simple, cheap, biodegradable, and efficient adsorbent in dispersive solid phase extraction of Cd(II) and Pb(II) ions from some oil samples including edible, fish oil, and butter. In the next step, a dispersive liquid-liquid microextraction method was used to enrich the extracted analytes before their analysis with flame atomic absorption spectrometry. For this purpose, the adsorbent was obtained from agricultural wastes, dried in an isolated environment at ambient temperature, and mechanically ground to obtain a homogeneous powder. The parameters affecting the efficiency of the method were optimized. Low detection limits (0.12 and 0.32 µg l-1 for Cd(II) and Pb(II), respectively), low relative standard deviations (3.8% and 4.2% for Cd(II) and Pb(II), respectively), and determination coefficients close to 1 (0.991 and 0.995 for Cd(II) and Pb(II), respectively) were achieved. Also, the extraction recoveries for the target analytes were 89 and 96% for Cd(II) and Pb(II), respectively. [ABSTRACT FROM AUTHOR]

In present study, efficiency of three rapid, simple, and reliable sample preparation methods namely dispersive liquid–liquid microextraction (DLLME), air-assisted liquid–liquid microextraction (AALLME), and CO2-assisted liquid–liquid microextraction (CO2-ALLME) have been compared for the extraction and preconcentration of Pt(IV) and Pd(II) ions in environmental water samples prior to flame atomic absorption spectrometry. In this regard, the effect of various experimental parameters on efficiency of the methods like nature and amount of the disperser and extraction solvents, ionic strength, temperature, pH, etc., are investigated to reach high enrichment factors. Due to organic solvent consumption at µL level, all of the studied methods are inexpensive and convenient. The linear ranges of the calibration curves were 10.0–200, 6.0–175, and 6.0–175 μg L−1 for Pd(II), and 20–200, 4.0–200, and 7.0–200 μg L−1 for Pt (IV) ions in DLLME, AALLME, and CO2-ALLME methods, respectively. Extraction recoveries of 81.4, 92.1, and 88.9% for Pd (II) and 85.3, 98.4, and 93.4% for Pt(IV) ions were obtained in DLLME, AALLME, and CO2-ALLME, respectively. Finally, the developed methods were successfully used for the analysis of Pt(IV) and Pd(II) in various water samples. [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]