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Abstract: This paper presents an electrochemical microsensor for simultaneous detection of copper (II) and lead (II) using an l-aspartic acid/l-cysteine/gold nanoparticle modified microelectrode. The microelectrode was fabricated by Micro Electro-Mechanical System technique. The complex of gold nanoparticles (AuNPs) and amino acid with carboxyl group was used as the selective ligand for metal ions. The microelectrode was firstly modified with AuNPs to increase the sensitive area of the working electrode. Subsequently, the AuNPs/gold electrode was modified with l-cysteine and then covalently linked with a monolayer of l-aspartic acid using glutaraldehyde. Electrochemical analysis of metal ions was achieved by using square wave voltammetry without stirring. The microsensor exhibited an excellent linear range from 5μgL−1 to 2000μgL−1 with the limit of detection of 1μgL−1. This metal ion detection method based on l-aspartic acid/l-cysteine/gold nanoparticle modified microelectrode is simple, sensitive and it could be used for electrochemical analysis of copper (II) and lead (II). [Copyright &y& Elsevier]

This work mainly describes an electrochemical microsensor based on the reduction of molybdophosphate complex for total phosphorus (TP) determinations in water. The microelectrode was fabricated using microelectromechanical systems (MEMS) techniques and porous, branching gold nanoparticles (AuNPs) were electrodeposited on the microelectrode to improve its sensitivity. Calibration of the microsensor was performed with standard phosphate solutions prepared with KH2 PO4 with pH adjusted to 1.0. The experimental results showed that both sensitivity and current response are improved effectively using this modified microelectrodes: The limit of detection of the microsensor is 1.2 × 10−7 mol/l and linear range is 3 × 10−7 to 3 × 10−4 mol/l. The sensitivity of unmodified electrode is −0.27 nA/μmol·l−1 (R2 = 0.994), whereas the sensitivity of AuNPs modified electrode is −0.89 nA/μmol l−1 (R2 = 0.98). The current response of modified electrode is 6 times larger than that of unmodified electrode in average. Detection of TP was also carried out with digested TP standard solutions for both modified and unmodified electrodes, and results were consistent with the nominal value of phosphorus concentration. This microsensor provides the probability of combining TP detection device with micro‐digesting device to form a TP detection system, which can realise the automotive and on‐line monitoring of TP in surface water. [ABSTRACT FROM AUTHOR]