Determination of zinc in environmental samples by solid phase spectrophotometry: optimization and validation study Molina, María Francisca Nechar, Mounir Bosque-Sendra, Juan M. Optimization Doehlert design Method validation Zinc Solid-phase spectrophotometry 4-(2-pyridylazo)resorcinol Sephadex QAE A simple and specific solid-phase spectrophotometric (SPS) determination of zinc in μg dm-3 level has been developed based on the reaction of Zn(II) with 4-(2-pyridylazo)resorcinol (PAR) in the presence of potassium iodide; the product was then fixed on an anionic exchanger. The absorbance of the gel, packed in a 1 mm cell, is measured directly. PAR and KI concentrations were optimized simultaneously using response surface methodology (RSM) from sequential experimental Doehlert designs. The advantages of this methodology are discussed, as opposed to univariate optimization, which is also used. The method was validated by obtaining the performance characteristics: linearity, detection and quantification limits, precision, robustness and selectivity, using suitable chemometric techniques; the trueness was confirmed on environmental samples (water and milk). 2014-07-03T10:31:05Z 2014-07-03T10:31:05Z 1998 info:eu-repo/semantics/article Molina, M.F.; Nechar, M.; Bosque-Sendra, J.M. Determination of zinc in environmental samples by solid phase spectrophotometry: optimization and validation study. Analytical Sciences, 14(4): 791-797 (1998). [http://hdl.handle.net/10481/32445] 0910-6340 http://hdl.handle.net/10481/32445 10.2116/analsci.14.791 eng info:eu-repo/semantics/openAccess Japan Society for Analytical Chemistry (JSAC)