Lab-on-a-Cable for Electrochemical Monitoring of Phenolic Contaminants

Abstract

The "Lab-on-a-Cable" concept, based on scaling down an electrochemical flow system to a cable platform, is described. The system integrates the analyte collection and the sample handling, with the electrochemical detection of the reaction product in a sealed cylindrical unit, connected to a long shielded cable. An enzymatic assay, involving collection of a phenolic substrate, its mixing with an internally delivered tyrosinase solution, and amperometric detection of the liberated quinone product, is used for illustrating the operation of the flow probe and demonstrating its advantages over remote phenol sensors. The internal buffer solution ensures independence of sample conditions such as pH, ionic strength, or natural conditions, that commonly influences the performance of remote sensors. The "built-in" flow pulsation of the integrated micropump is exploited for a sensitive hydrodynamic-modulation voltammetric detection of hydrazine and peroxide pollutants.

Emprego de monocamadas auto-organizadas no desenvolvimento de sensores eletroquímicos

“…Utilizando-se componentes biológicos, tais como enzimas e anticorpos, estes dispositivos têm demonstrado alta seletividade, sensibilidade e baixo custo, podendo ser empregados em métodos analíticos quase específicos para a determinação de compostos alvos 6,96,97 . Biossensores eletroquímicos têm apresentado grande potencial para sua aplicação em análises de alimentos, clínicas e de controle ambiental 6,98,99 . Um dos grandes desafios para a construção de biossensores mais sensíveis, robustos e de maior confiabilidade é a imobilização das biomoléculas sobre superfícies condutoras, em sua forma estável e com a manutenção de suas propriedades biológicas de reconhecimento 100 .…”

In situ electrochemical monitoring: from remote sensors to submersible microlaboratories

“…The ability to perform metal-ligand complexation reactions on a cable platform, in connection to adsorptive stripping measurements, has led to the development of submersible electrochemical analyzers [17]. As opposed to current in situ sensors (which lack the sample preparatory steps, essential for an optimal analytical performance), the new on-cable automated microanalyzer will eventually incorporate all the steps of the analytical protocol into the submersible device.…”

“…We also developed a submersible phenol analyzer, based on an enzymatic (tyrosinase) bioassay [17]. The assay involved microdialysis sampling of the phenolic compounds, their mixing with the internally delivered tyrosinase solution, and amperometric monitoring of the quinone product.…”

Analytical solution of the concentration and current in the electoenzymatic processes involved in a PPO-rotating-disk-bioelectrode

“…Owing to their specificity and sensitivity, enzyme electrodes including various amplification, schemes have been developed for many applications such as electrochemical immunoassays, [1][2] water pollutant detection, [3][4][5][6][7] and monitoring of biological metabolities [8][9][10][11]. The sensitivity of enzyme electrodes is very often increased by incorporation of a substrate-recycling scheme and several strategies including chemical, enzymatic, or electrochemical recycling have been developed.…”