A Palladium-Tin Modified Microband Electrode Array for Nitrate Determination

Abstract

A microband electrode array modified with palladium-tin bimetallic composite has been developed for nitrate determination. The microband electrode array was fabricated by Micro Electro-Mechanical System (MEMS) technique. Palladium and tin were electrodeposited successively on the electrode, forming a double-layer structure. The effect of the Pd-Sn composite was investigated and its enhancement of catalytic activity and lifetime was revealed. The Pd-Sn modified electrode showed good linearity (R2 = 0.998) from 1 mg/L to 20 mg/L for nitrate determination with a sensitivity of 398 μA/(mg∙L−1∙cm2). The electrode exhibited a satisfying analytical performance after 60 days of storage, indicating a long lifetime. Good repeatability was also displayed by the Pd-Sn modified electrodes. The results provided an option for nitrate determination in water.

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

“…[105] This sensor was able to detect nitrate in the range of 1 mg L -1 to 20 mg L -1 with a sensitivity of 398 µA/(mg L -1 cm 2 ). [105] Most recently, the same group developed a chemical sensor for nitrate detection based on an ultramicro IDA modified by Pd-AuNPs. [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.…”

“…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 .…”

“…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 . Second, a palladium–tin modified microband electrode array was developed for nitrate detection in fresh water with a long lifetime of over 60 days . 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 ) .…”

Palladium-Doped Tin Oxide Nanosensor for the Detection of the Air Pollutant Carbon Monoxide Gas

“…When studies were carried out with Pt-loaded SnO 2 and Pd-doped SnO 2 , the latter was found to be more selective for hydrogen giving a fast response [54]. The sensitivity and life-time was shown to be higher for Pd-tin reformed microband electrode series, as a nitrate sensor [55]. The sensors using Pd-doped TiO 2 fibers exhibited encouraging gas sensing characteristics like low operation temperature and adequate gas response [56].…”