In this study, a solid-phase extraction method combined with atomic absorption spectrometry for extraction, preconcentration, and determination of iron (Fe(3+)), copper (Cu(2+)), and lead (Pb(2+)) ions at trace levels in water samples has been reported. The influences of effective parameters such as flow rate, pH, eluent conditions (type, volume, and concentration), sample volumes, and interference of matrix ions on metal ions recoveries were studied. Under optimized conditions, the limits of detection were found in the range of 0.7-2.2 μg L(-1), while preconcentration factors for Fe(3+), Cu(2+), and Pb(2+) ions were found to be 166, 200, and 250, respectively, and loading half time (t (1/2)) values were less than 2 min for all analyte ions. The proposed procedure was applied for the determination of metal ions in different water samples with recovery of >94.4% and relative standard deviation less than 4.4% for N = 5.
The solubilities of chloroquine diphosphate and 4,7-dichloroquinoline in water, ethanol, tetrahydrofuran, acetone, and acetonitrile were measured over the temperature range of (298.2 to 333.2) K. The solubilities of both analytes in different solvents increase smoothly with temperature. On the basis of the solubility data, it can be observed that the highest solubilities for chloroquine diphosphate and 4,7-dichloroquinoline were obtained in pure water and tetrahydrofuran, respectively. The temperature dependence of the solubility data was correlated by the modified Apelblat model. The calculated solubilities show good agreement with the experimental solubility data in the temperature range studied.
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