Surface plasmon resonance optical sensor for detection of Pb2+ based on immobilized p-tert-butylcalix[4]arene-tetrakis in chitosan thin film as an active layer

Sensors and Actuators B: Chemical, Volumes 171–172, August–September 2012, Pages 287-293
Yap Wing Fen, W. Mahmood Mat Yunus, Nor Azah Yusof

Department of Physics, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia

Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia

Abstract

Recently, the presence of lead in the environment has been a great concern because of its increased discharge and possible toxic effects to human. Due to the dangerous toxic effect to human, several methods for determining Pb²⁺ have been developed include atomic absorption spectroscopy, inductively coupled plasma mass spectroscopy, electrochemical impedance spectroscopy, voltammetry and polarography. However, these methods generally are expensive and mostly take a long measuring period. Therefore, recent analytical interest has focused on developing optical sensors, which have the advantages of size, cost-effectiveness, simple preparation of sample, fast measurement capability and no necessity of reference solution. In this study, surface plasmon resonance (SPR) optical sensor, for sensitive and selective detection of Pb²⁺, was developed based on p-tert-butylcalix[4]arene-tetrakis (BCAT) immobilized in chitosan thin film as an active layer. Pb²⁺ can be detected by measuring the SPR signal when BCAT immobilized chitosan thin film is exposed to Pb²⁺ in aqueous solution. The BCAT immobilized chitosan thin film was coated on a gold layer by spin coating technique. The measurements were carried out for Pb²⁺ concentration ranging from 30 ppb to 5 ppm. A linear relationship between the shift of SPR angle and concentration of Pb²⁺ up to 1 ppm, with sensitivity of 0.045° ppm⁻¹ has been observed. Pb²⁺ can also be selectively detected when present in mixtures of heavy metal ions containing Cu²⁺, Hg²⁺, Zn²⁺ and Mn²⁺ ions.

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http://www.sciencedirect.com/science/article/pii/S0925400512003334