Fig. 4.

Normalized peak areas of glyphosate (10 µM) over time for different reference electrodes (RE) and potential waveforms. The used waveforms (1, 2, and 3) are depicted in Fig. 5. (a) Pd RE and waveform 1, (b) Ag/AgCl RE and waveform 1, (c) Ag/AgCl RE and waveform 2, (d) Ag/AgCl RE and waveform 3. Chromatographic parameters: column: Metrohm Metrosep A Supp18 (4 × 5 + 4 × 150 mm), 30 °C; eluents: A 20 mMNaOH, B 50 mM NaOH + 400 mM NaOAc; gradient profile: 0–3 min 5% B, 3–16 min 5–36% B, 16.1–18 min 50% B, 18.1–25 min 0% B. Detection: amperometric detector with gold WE and Pt CE; RE and waveform as denoted; detector temperature: 35 °C; injection volume: 50 µL