Bulk optode sensors for detection of lead ion

Abstract

A sensitive optode membrane based on highly lead-selective ionophore, chromoionophore (ETH 5294) and cation exchanger (KTpClPB) in plasticized PVC was fabricated. The optode membranes were used for determination of Pb[superscript 2+] by absorption spectrophotometry in batch and flow-through systems.The influence parameters such as pH solution,type of buffer, concentration of conditioning and regenerating solutions, time of condition and regeneration, and response time were studied. This sensor responded to Pb[superscript 2+] by changing color from blue to pink purple in TRIS buffer containing different concentrations of Pb[superscript 2+] at pH 7.0. The optode provided the response range of 3.16×10[superscript -8] to 5.00×10[superscript -5] mol L[superscript -1] Pb[superscript 2+] with detection limit of 2.49×10[superscript -8] mol L-1 in batch system within the response time of 30 min. The dynamic range of 1.26×10[superscript -8] to 3.16×10[superscript -5] mol L[superscript -1] Pb[superscript 2+] with detection limit of 8.97×10[superscript -9] mol L-1 were obtained in flow-through system within the response of 15 min. Moreover, the proposed optode membrane showed good selectivity toward Pb2+ over Na+, K+, Mg2+, Cd2+, Hg2+ and Ag+. It was successfully applied to determine Pb2+ in real water samples and the results were compared with inductively coupled plasma optical emission spectrometry (ICPOES). No significant different value was found between both methods at 95% of confidence level.