carrier elementfree coprecipitation for preconcentration of mn^2+, co^2+, ni2^+, cd^2+ and cu^2+ ions from water, brewed tea and tobacco samples

A preconcentration procedure, based on the coprecipitation of mn^2+, co^2+, ni^2+, cd^2+ and cu^2+ ions using a new organic coprecipitant, (2-(4-{[(4-{5-oxo-4-[1-(2-thienyl) methylidene]- 4,5-dihydro- 1,3- oxazole-2-yl} phenyl) imino] methyl} phenyl) methylidene ] amino} phenyl) -4-[ 1-phenyl methylidene] -1,3-oxazole-5(4h)-one (otmdo) without adding any carrier element has been developed. the resultant concentrated elements were determined by using flame atomic absorption spectrometer. the influences of some analytical parameters including ph, amount of the coprecipitant, standing time, centrifugation rate and time, sample volume and diverse ions were investigated on the quantitative recoveries of analyte ions. under the optimized experimental conditions, the calibration curves for the analyte ions were studied. the relative standard deviations for seven replicate determinations of a mixture of 0.1 µg ml^−1 mn^2+, co^2+, ni^2+, cd^2+ and cu^2+ ions in the original solution were 2.5, 2.4, 2.2, 2.1 and 2.5%, respectively. the detection limits based on 3sb/m for mn^2+, co^2+, ni^2+, cd2^+ and cu^2+ ions in the original solution were 1.2, 1.3, 1.2, 0.6 and 1.5 ng ml^−1, respectively. the proposed method has been applied for determination of trace amounts of the analyte ions in the standard, water samples; brewed tea; tobacco samples and satisfactory results were obtained.