Electrochemical Determination of Caffeine Content in Ethiopian Coffee Samples Using Lignin Modified Glassy Carbon Electrode

Figure 5

DPVs of lignin modified GCE in pH 4 ABS containing 1 mM caffeine at (a) different step potentials ((a)–(c): 4, 8, and 12 mV, resp.) and pulse amplitude of 50 mV and (b) different amplitudes ((a)–(d): 25, 50, 75, and 100 mV, resp.) and step potential of 8 mV.

(a)

(b)