Infrared Laser‐Induced Graphene Sensor for Tyrosine Detection

Abstract

In this work, we demonstrate that laser‐induced graphene (LIG) electrodes produced by a single‐step infrared irradiation on a commercially available polyimide sheet work as portable platforms for the electrochemical detection of tyrosine (Tyr). The LIG surface was characterized by Raman and scanning electron microscopy, which confirmed the formation of graphene with a highly porous structure. The sensor associated with differential‐pulse voltammetry provided the determination of Tyr with a linear range between 5 and 30 μmol L−1, a limit of detection (LOD) of 1.5 μmol L−1, precision of 6.2 % (n=10), and a satisfying selectivity towards interfering species found in biological media (e. g., dopamine, urea, and both ascorbic and uric acids). Artificial urine samples spiked with different amounts were analyzed by the proposed sensor and recovery values between 107 and 114 % were obtained. Opposite to many works reported in the literature, this platform did not require costly and time‐consuming surface modification processes, being an alternative feasible for other applications of clinical/medical interest. One LIG electrode sensor is produced in 140 s without chemical waste generation.

Rapid Quantification of Antioxidant Capacity in Tea Using Laser-Induced Graphene Electrodes

“…21 The other bands present in the spectrum (2D′, D + D″, and D + D′) are associated with combined harmonics. 22 All of these bands in the Raman spectrum of the LIG electrode suggest the formation of good-quality graphene-like material as observed in previous works. 22,25 In addition, the performance of LIG electrodes was evaluated using the electrochemical redox K 3 [Fe(CN) 6 ] solution (1 mmol L −1 ), and the obtained profile was as expected for this electrochemical probe.…”

“…22 All of these bands in the Raman spectrum of the LIG electrode suggest the formation of good-quality graphene-like material as observed in previous works. 22,25 In addition, the performance of LIG electrodes was evaluated using the electrochemical redox K 3 [Fe(CN) 6 ] solution (1 mmol L −1 ), and the obtained profile was as expected for this electrochemical probe. An anodic peak at +0.29 V and a cathodic peak at +0.14 V were observed (Figure 2C), which leads to a peak-to-peak separation (ΔE p ) value of 0.15 V. This value is comparable with the ΔE p values obtained with other disposable working electrodes.…”

“…A porous surface is observed in the SEM image, which is a result of the pyrolysis of PI. This partially regular morphology of porous graphene sheets has an average pore size of 3 μm, which was also observed in previous works in the literature. , …”

“…The signal at 2695 cm –1 refers to the two-dimensional (2D) band, originating from second-order zone boundary phonons . The other bands present in the spectrum (2D′, D + D″, and D + D′) are associated with combined harmonics . All of these bands in the Raman spectrum of the LIG electrode suggest the formation of good-quality graphene-like material as observed in previous works. , …”

“…This partially regular morphology of porous graphene sheets has an average pore size of 3 μm, which was also observed in previous works in the literature. 22,25 Raman spectroscopy plays an important role in the structural characterization of graphitic materials. Figure 2B shows the Raman spectrum of the obtained LIG electrode, which presents the characteristic bands of the graphene material.…”