Multivariate optimization of a new LC-MS/MS method for the determination of 156 pesticide residues in milk and dairy products.

Background: Pesticides are widely utilized worldwide to control undesirable life forms during the planting procedure in agriculture. But they can pollute the nature and jeopardize human wellbeing. Additionally, on account of high resistance and biological activity; pesticides are able to accumulate in living organs and lead to acute and long-term negative effects along with toxicity.

Efficient solid phase extraction of α-tocopherol and β-sitosterol from sunflower oil waste by improving the mesoporosity of the zeolitic adsorbent.

The recovery of α-tocopherol and β-sitosterol from the deodorizer distillate of sunflower oil using solid phase extraction is reported. Performance of the silicon-rich and inexpensive zeolite, ZSM-5, and its modified versions were compared as adsorbents. Modifications of the zeolite frame were performed under both acidic and basic conditions to desilicate and dealuminate the parent ZSM-5.

Solid Phase Extraction of Trace Al(III), Fe(II), Co(II), Cu(II), Cd(II) and Pb(II) Ions in Beverages on Functionalized Polymer Microspheres Prior to Flame Atomic Absorption Spectrometric Determinations.

In this study, poly(glycidyl methacrylate-methyl methacrylate-divinylbenzene) was synthesized in the form of microspheres, and then functionalized by 2-aminobenzothiazole ligand. The sorption properties of these functionalized microspheres were investigated for separation, preconcentration and determination of Al(III), Fe(II), Co(II), Cu(II), Cd(II) and Pb(II) ions using flame atomic absorption spectrometry. The optimum pH values for quantitative sorption were 2 - 4, 5 - 8, 6 - 8, 4 - 6, 2 - 6 and 2 - 3 for Al(III), Fe(II), Co(II), Cu(II), Cd(II) and Pb(II), respectively, and also the highest sorption capacity of the functionalized microspheres was found to be for Cu(II) with the value of 1.

A New Dispersive Liquid-Liquid Microextraction Method for Preconcentration and Determination of Aluminum, Iron, Copper, and Lead in Real Water Samples by HPLC.

In this study, dispersive liquid-liquid microextraction coupled with HPLC with variable-wavelength detection was applied for the simultaneous determination of Al, Fe, Cu, and Pb in various water samples at trace levels. In the proposed method, all the system parameters in both the extraction and separation/determination steps, such as extraction and disperser solvent type and their volumes, complexing reagent concentration, salt addition, extraction and centrifugation times, and pH, were optimized to get not only high extraction efficiency but also lower LODs for the analytes. Hematoxylin was used as a complexing reagent, and carbon tetrachloride and methanol were chosen as the extraction and disperser solvents, respectively.