A Pt Nanoparticle Electrode for Nitrite Determination in Solution

In this study, a Pt nanoparticle electrode which had advantages of high selectivity, accuracy, and anti-interference capacity was successfully fabricated for quantitative measurement and analysis of nitrite concentration under neutral conditions with various interference ions. Current-time curve was used for the electrodeposition of Pt nanoparticles on the surface of the pretreated Pt disk electrode, and the deposition time was 100 seconds. The prepared nano-Pt electrode had an electrochemical catalytic reductive activity for nitrite. Nitrite reductive peak current was linear correlation with nitrite concentrations in solutions. The life time of the modified electrode was at least 150 days at room temperature (at least 1000 determinations). The present method is simple, does not require any pre-treatment procedure, and does carry very good repeatability and reproducibility. Moreover, the proposed electrochemical method was also validated by spectrophotometry in artificial and real wastewater samples. © 2014 The Electrochemical Society. [DOI: 10.1149/2.058404jes] All rights reserved. Nitrite is strongly related to our life, which is also commonly in environment and food. Currently, more and more nitrogen fertilizer is used to promote plant growth and improve agricultural production. It can be easily lost and then flew into the water when rainfall or irrigation is occurred. Nitrite, as one kind of nitrogen fertilizer, can be easily transformed into nitrate in the water. If nitrite and nitrate flow into the slow flowing water such as estuary, lake, bay and so on, they will lead to water eutrophication and then aquatic ecosystem will be disordered, aquatic organism will be reduced, and biodiversity will be destroyed. Although nitrite is universally used as an additive in some food, such as a preservative of food and a color fixative for meats, it is easily converted to N-nitrosamine, which is a strong carcinogen by reaction with the secondary amines, tertiary amines and amides in the gastricacidenvironment. 1 Nitritecontainedinfoodanddrinkingwater causes serious health risks for human beings, for instance, ingestion of nitrite from 0.3 ∼ 0.5 g can cause poisoning, approximately 3 g cancausedeath.Furthermore,nitritecancauseoxygen-deficiencyand further lead to methemoglobinemia in the human blood. 2 In summary, nitrite is ubiquitous within the environment, especially water, it can lead to water eutrophication when nitrite concentration is too high and is a great threat to human health. So environmental monitoring must on-line monitor nitrite concentration in domestic sewage, industrial waste and agricultural drainage, and strictly control the content of nitrite in water. Recently, the determination of nitrite concentration in water has been widely recognized, and much attention is paid on the method to determine it fast and accurately. There are many ways to determine nitrite concentration in water, commonly by spectrometry, 3‐5 ion chromatography, 6,7 chemiluminescence, 8 and electrochemistry. 9‐11 Since spectrometry and ion chromatography will be susceptible to interference from other ions in water when it is used to determine the concentration of nitrite, So the sample need to pretreated before measured, analytical cycle becomes long and operation becomes complicated. The detection time of chemiluminescence is shorter than spectrometry and ion chromatography and increase the detection limit, but the detection system becomes more complex and the temperature of combution is high. To overcome these disadvantages, electrochemical methods are promising in the detection of contaminant as exhibiting high selectivity, 12,13 not requiring the pretreatment of sample, 14,15 quickly determining (response time, 17 s), 16 linearity over a wide concentrationrange(9.8 ×10 −6 −1.0 ×10 −1 M) 17,18 andlowcost. 19 Thus, it has been paid more and more attention, as well as more research by