Electrochemical diamond sensors for TNT detection in water

An electrochemically stabilized boron doped diamond electrode prepared by chemical vapour deposition (CVD) is used for electrochemical TNT sensing in aqueous solutions. Square wave voltammograms (SWVs) exhibit three highly resolved peaks at −0.47, −0.62 and −0.76 V vs. Ag–AgCl reference electrode, respectively. The current vs. TNT concentration plot shows a linear relationship with a same slope for the two first TNT peaks at μg L⁻¹ and mg L⁻¹ concentration ranges. Detection and quantification limits of 10 and 25 μg L⁻¹, respectively, were obtained without any preconcentration step. Relative standard deviation (RSD) of less than 1% measured over 10 runs has been found for the −0.47 V peak current showing the very high stability of the electrode without any significant fouling effect. An interference study with nitro aromatic compounds of the same family (nitro toluene and dinitrotoluene) has shown that the −0.47 V reduction peak enables TNT discrimination. Measurement of TNT in a natural medium (sea water without any purification step except filtering) has been also investigated.