Palladium-Gold Modified Ultramicro Interdigital Array Electrode Chip for Nitrate Detection in Neutral Water

Abstract

An ultramicro interdigital array electrode modified by palladium-gold was developed for nitrate detection in neutral water. The ultramicro interdigital array electrode was fabricated based on silicon substrate by Micro Electro-Mechanical System (MEMS) technique. The nanostructured palladium-gold (Pd-AuNPs) composite sensing film was electrodeposited on the surface of a working electrode by electrochemical method. The synergistic effect of Pd-AuNPs composite was investigated and its enhancement of the catalytic activity and stability was revealed. The Pd-AuNPs modified electrode showed good linearity (R2 = 0.99) from 1 mg/L to 15 mg/L (as N) for nitrate determination in a neutral water environment (pH = 7.2), with a sensitivity of 4.7 μA·mg−1·L. The results showed that the developed Pd-AuNPs-modified ultramicro interdigital array electrode chip can achieve sensitive and environmentally-friendly detection for nitrate in neutral water.

Band Electrodes in Sensing Applications: Response Characteristics and Band Fabrication Methods

“…[106] The sensing layer (Pd-AuNPs) was electrodeposited on the electrode surface and showed a good linearity from 1 mg L -1 to 15 mg L -1 in neutral water conditions. [106] Figure 15 The fabrication process and a photograph of a gold microband array electrode. The diameter of the coin is 19 mm.…”

“…Xia and his co-workers reported several papers on the analysis of water based on microband electrode arrays. [104][105][106] In one, a microsensor based on gold microband array for the determination of phosphate in fresh water was fabricated where gold nanoparticles (AuNPs) were deposited on the electrode surface to improve the sensitivity. [104] The fabrication process and the structure of the electrode is shown in Figure 15; the modified electrode gave a sensitivity of 7.66 µA per (mg P.L) which is three time larger than the unmodified electrode.…”

“…This sensor was able to reach a low LOD of 0.8 ppb (in 4 M HCl electrolyte), which is lower than the World Health Organisation limit of 10 μg L –1 (ppb), offering a cost-effective device with a high sensitivity for arsenic analysis in drinking water. Xia and his co-workers reported several papers on the analysis of water based on microband electrode arrays. − In one, a microsensor based on a gold microband array for determination of phosphate in fresh water was fabricated where gold nanoparticles (AuNPs) were deposited on the electrode surface to improve the sensitivity . The fabrication process and the structure of the electrode is shown in Figure ; the modified electrode gave a sensitivity of 7.66 μA per (mg P.L) which is three time larger than the unmodified electrode .…”

“…This sensor was able to detect nitrate in the range of 1 to 20 mg L –1 with a sensitivity of 398 μA/(mg L –1 cm 2 ) . Most recently, the same group developed a chemical sensor for nitrate detection based on an ultramicro IDA modified by Pd-AuNPs . The sensing layer (Pd-AuNPs) was electrodeposited on the electrode surface and showed a good linearity from 1 to 15 mg L –1 in neutral water conditions …”

Copper nanowire array as highly selective electrochemical sensor of nitrate ions in water

“…Different type of electrochemical sensors have been exploited in order to quantify nitrates, such as impedimetric [21]; [22], chronoamperometric [23][24][25][26][27], voltammetric [28]; [29][30][31][32][33] and also biosensors [34,35], [36]. As concern the enzymatic biosensors they permit to obtain very low Limit Of Detection (LOD) but the detection is very hard, expensive and time consuming (accurate pH control, many separation and incubation steps) [37].…”