Electrochemical Sensors for the Detection of Tricresyl Phosphate and Determination of Acid Content in Engine Oils

Abstract

Electrochemical sensors were developed in this study for the detection of tricresyl phosphate (TCP), a toxic chemical found in airline cabins and determination of acid accumulation in engine oils upon extended usage. A hydrolyzing column was developed that hydrolyzed TCP to electro-active cresols which were detected using a copper-nanoparticle-multi-walled carbon nanotubes modified glassy carbon electrode. The problem arised due to electrode fouling was solved using Sodium 3,5 dibromo-4-nitroso benzene sulfonate (DBNBS) reagent. An automated sensor was developed using LabVIEW® by integrating the hydrolyzing column, modified electrodes and potentiostat for on-site detection of TCP in airline cabins.

With extended usage, engine oil accumulates several acids by incomplete oxidation which increases the acid content of the oil. Iridium oxide coated titanium electrodes were fabricated to determine the increased acid content in artificially aged oils whose trend was in accordance with the Total Acid Number (TAN) values found by potentiometric titration. The pH sensing properties of iridium oxide were exploited for the detection of paraoxon, a toxic organophosphorus compound. An enzyme immobilized multi-channel pH sensing block was fabricated for its detection.