Application of modified organo-nanoclay as the sorbent for zinc determination by FAAS: an optimization study of an...

An online column pre-concentration technique, coupled with flame atomic absorption spectrometry, was developed using a column filled with nanoclay modified with morin. For this purpose, zinc was determined in the water and biological samples. The sample solution was passed through the modified nanoclay column. The adsorbed zinc was subsequently eluted from the column with nitric acid solution. The optimization step was performed using two-level fractional factorial (2(5-2)) and Box-Behnken designs. Firstly, the fractional factorial design was performed for preliminary evaluation of the significant factors. The results showed that pH, amount of morin, and concentration of eluent were significant. The Box-Behnken experimental design was carried out in order to determine the optimum conditions. The optimum conditions were found to be at pH 5.8, 1.8 mg L(-1) of morin and 3.0 mol L(-1) of eluent concentration. Under these optimum conditions, the limit of detection was found to be 0.11 μg L(-1). Furthermore, the relative standard deviation of the ten replicate determinations was <2.8.0%. The method was validated by analyzing the zinc using a certified reference material that is NRCC-SLRS-4 riverine water. The developed procedure was applied to the extraction and determination of zinc in the water and biological samples.