Electrochemical preconcentration of ultra-trace Cd~(2+) from environmental and biological samples prior to its determination using carbon paste electrode impregnated with ion imprinted polymer nanoparticles

摘要

Cadmium (Cd) is known as one of the most toxic elements among the heavy metals. This study proposes an electrochemical preconcentration method using the ion imprinted polymer nanoparticles modified carbon paste electrode (IIP-CPE) for the stripping voltammetry determination of Cd2+ in the environmental and biological samples. These IIP NPs were synthesised using ethylene glycol dimethacrylate as the cross-linker, 2,2MODIFIER LETTER PRIME-azobisisobutyronitrile as the free radical initiator and 4MODIFIER LETTER PRIME-(4-vinylphenyl)-2,2MODIFIER LETTER PRIME:6MODIFIER LETTER PRIME,2"-terpyridine as the Cd-binding ligand. The calibration plot was linear in the concentration range of 4-500 nM (R-2 = 0.9936) with a sensitivity of 918 mu A mu M-1 cm(-2). The LOD based on 3S(b)/m (where m is the slope of the calibration curve and S-b is the standard deviation for five blank measurements) was found to be 1.94 nM. The relative standard deviations (RSDs) for single-electrode repeatability and electrode-to-electrode reproducibility were 3.0% and 5.6% (n = 5), respectively. The accuracy of the current method was confirmed by the analysis of urine quality control material (QCM, Seronorm(TM) Trace Elements Urine, REF NO 201205, Norway) and spiked blood, rice and water samples. Recoveries were found to be above 95.0% for all samples, which confirms the good performance of the proposed voltammetry method.