Selective Determination of p‐Nitrophenol Based on Its Unique Voltammetric Behavior on Nanoporous Gold

Abstract

In this paper, an unsupported nanoporous gold (us-NPG) was applied as a novel electrochemical sensor material for the selective detection of p-nitrophenol (p-NP) among its isomers in acid solution based on the distinct cyclic voltammetric behavior. To ascertain the ascription of each peak in cyclic voltammograms (CVs) of three nitrophenol isomers (NPs) on the us-NPG, contrast voltammetric studies of NPs were conducted at an ultrathin NPG film supported on glassy carbon substrate (NPG/GC) and a well-defined Au(111) electrode, respectively. Effects of potential scan rate and rotation speed of the electrode on the redox reaction of NPs were investigated to further confirm the reaction mechanisms. Interestingly, unlike those obtained on NPG/GC and Au(111) electrodes, the CVs of both o-nitrophenol (o-NP) and m-nitrophenol (m-NP) on us-NPG presented a new pair of redox waves separated very well from the redox waves of p-NP, indicating an obviously different mechanism involved in the redox process. Based on the voltammetric behavior, trace level determination of p-NP can be achieved on us-NPG electrode in the presence of o-NP and m-NP. Thus, the fast electron transfer, high selectivity and good sensitivity make us-NPG act as an ideal electrochemical sensor material in the selective determination of p-NP in aqueous solutions.

Nanoporous Gold Electrodes and Their Applications in Analytical Chemistry

“…The ability to use an electrode that has an electrochemically useful surface area that is 10-100 times larger than a traditional electrode thus offers much promise. Examples of small molecules that have been studied include dopamine [144], ascorbic acid [144], hydrogen peroxide [143,145], nitrite [146], cysteine [147], nitrophenol [148,149], hydrazine [150], and glucose [151].…”

“…The electrochemical detection of nitrophenol using a nanoporous gold electrode has also been reported [148,149]. Different electrochemical behavior has been observed on nanoporous gold versus planar gold particularly as it pertains to the different isomers of nitrophenol.…”

“…Different electrochemical behavior has been observed on nanoporous gold versus planar gold particularly as it pertains to the different isomers of nitrophenol. An interesting aspect of these studies is that p-nitrophenol can be detected even in the presence of ortho-and metaisomers [148,149]. A detection limit of 0.02 mg/dm 3 was reported at an unsupported nanoporous gold electrode [148].…”

Highly sensitive and selective electrochemical detection of L-cysteine using nanoporous gold

“…Meanwhile, both good conductivity and high specific surface area make NPG as fascinating electrochemical sensor material [27][28][29], and a good choice for the electrochemical detections of organic molecules for environmental and biomedical analysis. In this paper, we investigated the details of CySH oxidation at an NPG coated glass carbon (GC) electrode with an emphasis on its potential implementation as highly sensitive and selective sensor for detection of CySH.…”

Mechanical Properties of Nanoporous Au: From Empirical Evidence to Phenomenological Modeling

“…NP Au-based sensors have shown remarkable selectivity towards specific prostate antigens [79] and probe DNA [80]. In addition, NP Au has been shown to allow effective electrochemical sensing of p-nitrophenol molecules [81], as well as the rapid measurement of Escherichia coli bacteria concentration in food and water [82]. Similarly, NP Au-based detectors for neural activity provided a superior signal-to-noise ratio due to low electrode-electrolyte impedance [83].…”