Design and Development of Electrochemical Nanosensor based on CarbonCeramic Electrode modified using Molecular Imprinted Membrane forDetermination of GALLIC ACID

Publish Year: 1395
نوع سند: مقاله کنفرانسی
زبان: English
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ELECTROCHEMISTRY012_196

تاریخ نمایه سازی: 5 آذر 1397

Abstract:

Gallic Acid (3,4,5–trihydroxybenzoic acid) (GA) is one of the main natural phenolic components.It is extensively used in tanning, ink dyes, manufacturing of paper, food industry, and drugtrimethoprim in the pharmaceutical industry [1, 2]. Rapid and accurate detection of GA is of greatinterest to analytical chemistry because it has not only strong anti-mutagenic, anti-carcinogenic,and anti-oxidant activities but also potential health effects which have been found recently [3]. Inpast years, various methods have been applied to determine GA, such as flow injection analysis[4, 5], resonance light scattering [6], thin–layer chromatography [7], reversed phase highperformanceliquid chromatography [8], and electrochemical method [9,10]. With regard to theconducted surveys, no MIP-based chemical sensor has been presented so far for determination ofGA. However, MIP has been used to separate GA from aqueous samples. In the present study, asensitive electrode is developed to determine GA in very low concentrations. MIP, containingrecognition sites for GA, is synthesized by electropolymerization of aniline on carbon ceramicelectrode in present of GA. For optimization of separation and determination of GA in solutions,operational parameters include pH solution, pre-concentration time of nanosensor in GA solutionand solution temperature was chosen and optimized via central composite design. Using Design–Expert 8.0.2 software, a complete CCD matrix include 20 experiments was designed. Theoptimal conditions for determination of GA nanosensor were solution pH= 3.62, accumulationtime=45 min and 45 °C as solution temperature. In order to confirmation of improvement thenanosensor performance due to creation an molecular imprinted membrane (MIM) on carbon ceramic electrode (CCE) in determination of GA, DPV of four different electrode such as CCE,multiwall carbon nanotube modified CCE (MWCNT/CCE), electropolymerized MWCNT/CCEin absence of GA (ENIM) and in presence of GA (EMIM) was measured based on these optimumconditions. The mentioned electrodes were separately immersed into a 1.0 mM GA solution withthe pH of 3.62 at 45 ˚C for 60.0 min until GA accumulated on the electrodes. After accumulationof GA molecules on the electrodes, they were washed with a water-ethanol (50% v–v) solutionand displaced to a phosphate buffer solution with the pH of 7.0. Their DPVs are depicted in Fig1. As it can be seen, there is no significant reduction current for GA on CCE (curve a) andENIM/MWCNT/CCE (curve c). Indeed, CCE and ENIM/MWCNT/CCE have no capability fortrapping and accumulating of GA. On the other hand, by comparing DPVs of CCE (curve a) andMWCNT/CCE (curve b), it can be conclude that cathodic peak current is increased due to thepresence of MWCNT. It seems that a possible reason for the increase of current is the presence ofMWCNT in the electrode structure; MWCNT has a larger surface area and higher conductivitythan graphite. However, EMIM/MWCNT/CCE (curve d) is considerably indicate the current forreduction of GA. Thus, the prepared electrode is able to trap GA molecules. Under optimalexperimental conditions, DPVs of EMIM/MWCNT/CCE was recorded to estimate the lowerlimit of detection and the linear range of GA. As expected, the reduction peak current increasedupon the increase of GA concentration. Fig 2 clearly indicates that the plot of the reduction peakcurrent against the GA concentration was linear in the range of 10–500 mM. According to themethod mentioned in Skoog et al. (1998), the lower detection limit, Cm, was calculated 6.5 mMby using the equation Cm=3sbl/m, where sbl is the standard deviation of the blank response and mis the slope of the calibration plot (0.006 mA mM). The average voltammetric peak current and theprecision estimated in terms of the coefficient of variation for repeated measurements (n = 15) of6.5 mM GA at the EMIM/MWCNT/CCE were 0.295 ± 0.007 mA and 2.4 %, respectively.

Authors

Farnaz Kafi

Department of Textile and Polymer, Yazd Branch, Islamic Azad University, Yazd, Iran.

Navid Nasirizadeh

Department of Textile and Polymer, Yazd Branch, Islamic Azad University, Yazd, Iran.

Mohammad Mirjalili

Department of Textile and Polymer, Yazd Branch, Islamic Azad University, Yazd, Iran.