Experimental Reagents and chemicalsAll chemicals used were of analytical grade. Cr(III) and Cr(VI) stock solutions (1000 mg L Poly(1,3-thiazol-2-yl methacrylamide-co-4-vinyl pyridine-co-divinylbenzene) was prepared and used as a sorbent for the solid-phase extraction of Cr(VI) ions from aqueous solution. Two forms of chromium showed different exchange capacities at different pH values; Cr(VI) was selectively retained especially at pH 2. The total chromium was determined after the oxidization of Cr(III) to Cr(VI) by potassium permanganate as an oxidizing agent. Then, Cr(III) was calculated by subtracting the Cr(VI) concentration from the total chromium concentration. The optimum conditions were found for species of Cr(VI) (pH 2; eluent, 4 mol L -1 NH3; sample flow rates, 2 mL min -1 and eluent flow rates, 1 mL min -1 etc.). The adsorption capacity and binding equilibrium constant were calculated to be 80.0 mg g -1 and 0.018 L mg -1 , respectively. A preconcentration factor of 30 and a three-sigma detection limit of 2.4 μg L -1 (n = 20) were achieved for Cr(VI) ions. The developed method was applied to stream water and waste water samples. At the same time, the polymer was applied to a certified reference material (CRM) (TMDA-52.3) sample.

A new method was developed to determine pesticide residues in fruit and vegetable extracts with short time analysis. An optimum results were achieved using binary mobile phase consisting of (methanol: water; 95:5, v/v) and fluorescence detection (λEx and λEm set at 280 and 340 nm, respectively) was used. The dynamic range was between 0.100 to 10 mg L -1 with relative standard deviation less than 0.45%, (n=4). Limits of detection and recoveries for carbendazim and chlorpyrifos were 0.073 mg L -1 (84.2-106.5%) and 0.062 mg L -1 (85.7-90.3%), respectively. The results revealed that the concentrations of carbendazim and chlorpyrifos residue in all collected samples were below than the EU legal limit.