Determination of cadmium in leaves by ultrasound-assisted extraction prior to hydride generation, pervaporation and atomic absorption detection.
A flow injection-pervaporation approach, where the samples--beech or olive leaves--were introduced as slurry, has been used for continuous derivatization hydride generation and separation of cadmium prior to determination by atomic absorption spectrometry. The removal of the analyte is achieved with an 1mol/l HCl+16% H(2)O(2) aqueous solution with the help of an ultrasound probe acting for 17 min. Thiourea and cobalt were also added to the slurry for kinetic catalysis of hydride generation. A CRM - beech leaves - where the analyte had not been certified but estimated was used for optimisation of the leaching step. The results obtained using direct calibration against aqueous standards demonstrated the reliability of the method. The linear concentration range of the calibration curve was from pg/ml to ng/ml, with a correlation coefficient, r(2), better than 0.99. The detection and quantification limits were 0.3 and 0.9ng/ml, respectively. The relative standard deviation for within-laboratory reproducibility was 5.7%. Olive leaves CRM was used for validation.
Caballo-López
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A
Department of Analytical Chemistry, Annex C-3, Campus of Rabanales, University of Córdoba, E-14071 Córdoba, Spain.
Luque de Castro
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MD