Influence of CTAB on the electrochemical behavior of dopamine and on its analytic determination in the presence of ascorbic acid

Abstract

This research work concerns the electrochemical study of dopamine and ascorbic acid in the presence of the cationic surfactant cetyltrimethylammonium bromide. From this study is possible to note that the cetyltrimethylammonium bromide greatest influence was on the dopamine, because it disfavors both its oxidation and reduction, thereby giving a smaller heterogeneous rate constant, k 0 , value than in its absence, provoking that the process tends to irreversibility. On the contrary, for the ascorbic acid case, its oxidation was favored; these effects can influence the separation of the dopamine and ascorbic acid voltammetric signals up to 453 mV. Further, the method could be optimized through differential pulse voltammetry to proceed with the analytic determination of dopamine in the presence of ascorbic acid displaying usable analytic parameters, namely: a linearity range of 0-130 lM, a sensitivity of (6.318 ± 0.002) lA mM -1 , a detection limit of (11 ± 0.1) lM, and a quantification limit of (37 ± 0.2) lM, which made it possible to effect the quantification on a commercial pharmaceutical sample.

Highly Sensitive and Selective Detection of Dopamine at Poly(chromotrope 2B)-Modified Glassy Carbon Electrode in the Presence of Uric Acid and Ascorbic Acid

“…The linear range and detection limit were comparable with those of other CP-based sensors. The PCHAGCE sensor exhibited a sensitivity of 1.522 AE 0.032 mAÁmM À1 , which is much higher than that of the previously reported DA sensor [11,12,20,28,31,[35][36][37][46][47][48][49], as shown in Table 1. Similarly, no obvious change in response was observed while varying the concentrations of UA in the presence of constant concentrations of AA and DA, and the peak current of UA increased linearly in the concentration range up to 160 mM with a correlation coefficient of 0.99 and a detection limit of 1.5 AE 0.03 mM (S/N = 3) (Fig.…”

“…Various approaches, such as modification of the electrode by covalent bonding [4], conducting-polymer (CP) films [7], and nanomaterials [8], as well as the use of a carbon paste electrode (CPE) with the assistance of sodium dodecyl sulfate (SDS)) [9,10,11] or cetyltrimethlammonium btomide (CTAB) [12] and electrochemical pretreatment of the electrode [13], have been developed to selectively differentiate these compounds. CP-modified electrodes prepared by electropolymerization have received extensive interest for the detection of various analytes because of their enhanced selectivity and sensitivity in addition to the homogeneity and strong adherence of the CP film to the electrode along with the excellent chemical stability of the CP film [14,15].…”

Electrochemical behavior of poly (naphthol green B)-film modified carbon paste electrode and its application for the determination of dopamine and uric acid

“…The detection limit (LOD) of DA and UA at the poly (NGB)-film modified CPE from 5 different calibration curves were found to be 0.25 ± 0.05 lM for DA and 5 ± 0.04 lM for UA respectively [42][43][44]. The LOD was calculated using the following equation, LOD = 3 S/M where, S is the standard deviation and M is the slope (sensitivity) obtained from the calibration curves [45].…”

Voltammetric resolution of dopamine in the presence of ascorbic acid and uric acid at poly (calmagite) film coated carbon paste electrode

“…To study the effect of concentration of DA, differential pulse voltammetric technique was used [20][21][22]. The concentration of DA was varied from 9 × 10 −6 to 35 × 10 −6 M. Fig.…”