Copper germanate nanowire electrode for the electrochemical detection of glyoxalic acid using cyclic voltammetry method

Figures & data

Figure 1. Schematic of the electrochemical working station.

Figure 2. SEM image of the CuGeO₃ nanowire modified GCE.

Figure 3. CVs of the bare GCE in 0.1 M KCl solution in absence (a) and presence (b) of 2 mM glyoxalic acid. CVs of the CuGeO₃ nanowire modified GCE in 0.1 M KCl solution in absence (c) and presence (d) of 2 mM glyoxalic acid, scan rate, 50 mVs⁻¹.

Figure 4. CVs of the CuGeO₃ nanowire modified GCE in the mixed solution of 2 mM glyoxalic acid and different electrolytes. Scan rate, 50 mVs⁻¹. (a) KBr, (b) NaOH, (c) H₂SO₄, (d) CH₃COONa-CH₃COOH.

Figure 5. CVs of the CuGeO₃ nanowire modified GCE in the mixed solution of 0.1 M KCl and 2 mM glyoxalic acid using different scan rates. The inset in the bottom-left part is the calibration plots of the intensities of anodic peaks against the scan rate.

Table 1. Analytical data of the glyoxalic acid.

CV peaks	Regression equation^.a	Correlation coefficient (R)	Linear range (mM)	Detection limit (μM)^b
cvp1	Ip = 9.748 + 37.526C	0.991	0.01–2	8.5
cvp2	Ip = 20.567 + 91.067C	0.998	0.001–2	0.78

^aWhere I_p and C represent the peak current (μA) and the concentration of the glyoxalic acid (mM).

^bThe detection limit of the glyoxalic acid was analysed using a signal-to-noise ratio of 3 (S/N = 3).

Figure 6. CVs of the glyoxalic acid with different concentrations at the CuGeO₃ nanowire modified GCE. KCl, 0.1 M, scan rate, 50 mVs⁻¹. The inset in the bottom-left part is the calibration plots of the intensities of anodic peaks against the concentrations of the glyoxalic acid.

Figure 7. CV of the CuGeO₃ nanowire modified GCE in 0.1 M KCl solution with 2 mM glyoxalic acid recycling for the 20th time. Scan rate, 50 mVs⁻¹.