A new sorbent of modified MWCNT for solid phase extraction and determination of trace amount of palladium in environmental samples

Abstract

A simple method for separation and preconcentration of trace amount of palladium from aqueous medium prior to its flame atomic absorption spectrometric determination was developed. 4,4-Bis(dimethylamino)thiobenzophenone-modified multiwalled carbon nanotubes (MWCNTs) as a new solid phase extractant has been packed in a column. The modification process was fast and simple and the sorbent showed relatively fast kinetics of sorption of the target analyte. Various parameters influencing the preconcentration of Pd were optimized, including pH of the solution, flow rate of sample and eluent, type and concentration of eluent and breakthrough volume, also interferences were studied. The sorption capacity of oxidized MWCNTs for Pd(II) was 19.8 mg/g. Under optimum experimental conditions, linearity range was from 1.2 to 200 ng/mL, the limit of detection of this method for Pd was 0.4 ng/mL with an enrichment factor of 200, and the relative standard deviation (RSD) was 3.7% at the 50 ng/mL Pd level. The method was validated by the extraction and determination of Pd(II) in rain water, blood, dry tea and road dust samples.