Low-cost electrochemical detection of l-tyrosine using an rGO–Cu modified pencil graphite electrode and its surface orientation on a Ag electrode using an ex situ spectroelectrochemical method

Abstract

A low cost reduced graphene oxide–copper hybrid nano thin-film modified pencil graphite electrode has been employed to detect the l-tyrosine enantiomer.

Disposable Electrochemical Sensor Using Graphene Oxide–Chitosan Modified Carbon-Based Electrodes for the Detection of Tyrosine

“…Due to the electric double layer (EDL) mechanism, fast charge/discharge processes, and higher ohmic resistance, the oxidation peak current (Ip) of Tyr increases as the potential scan rate increases (Figure 5a). The oxidation peak also shifts from 670 mV to a more positive potential of 710 mV, typical of irreversible surface controlled electrochemical processes [36]. A linear relationship between the Ip and the square root of the scan rate (v 1/2 ) has also been demonstrated (Figure 5b), indicating diffusion-controlled reaction kinetics: Ip = 3.57 ν 1/2 (mV s -1 ) -9.1531 (R 2 = 0.9833) (…”

“…This decrease in sensitivity is likely due to saturation of the electro-catalytic ability of the GO-CS-SPCS and kinetic limitation [36,55].…”

“…Despite the many recent advances in disposable and wearable sensing technologies for POCT, current systems are primarily focused on a limited number of metabolites, and few low-cost, flexible, and disposable sensors are available for Tyr POCT [1,2,33]. Most of the current approaches use complex or time-consuming fabrication processes that require sophisticated instrumentation, or solid electrodes, such as glassy carbon electrodes (GCEs), carbon paste electrodes (CPEs) or graphite pencil electrodes, etc., that are not suitable for single-use disposable systems (Table 1) [1,2,26,[33][34][35][36][37][38]. As an alternative, disposable screen-printed electrodes (SPEs) offer fast, affordable, and widespread testing at the point of care, without the need for skilled analysts or complicated measuring equipment [39][40][41].…”

Development of Polypyrrole Modified Screen-Printed Carbon Electrode Based Sensors for Determination of L-Tyrosine in Pharmaceutical Products

“…The usual voltamperometric methods used for L-Tyr detection reported in the literature are differential pulse voltammetry [ 34 ], cyclic voltammetry [ 35 , 36 ], chronoamperometry [ 37 ], linear sweep voltammetry [ 38 , 39 ], and square wave voltammetry [ 40 ].…”

“…Few studies have reported PPy doped with sodium dodecyl sulfate (SDS), potassium hexacyanoferrate (II) (FeCN), sodium Nitroprusside (NP), dodecylbenzene sulfonate (DBS), and p-toluene sulfonate (PTS) in different organic solvents or in aqueous environments, which could lead to high performances, respectively high conductivity, high thermic stability, reproducibility, etc. [ 34 , 35 ]. One advantage of electrochemical synthesis is the possibility of carrying out the deposition on the electrode and the doping of the polymer in one stage, a procedure useful in the case of electrochemical sensor development [ 46 ].…”