Fig. 6.
Chromatograms of seven different phosphonates. 20 μM of each compound: 1 = AMPA (a) and glyphosate (b), 2 = 2-aminoethylphosphonic acid (2-AEP), 3 = 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP), 4 = methylphosphonic acid (MPA), 5 = phosphonoacetic, acid (PAA), 6 = phenylphosphonic acid (PPA). Chromatographic conditions: column: Thermo Scientific Dionex AS16 (2 × 5 + 2 × 250 mm) at 30 °C; eluents A: 15 mM NaOH, B: 50 mM NaOH + 400 mM NaOAc; flow rate: 0.3 mL/min; gradient profile: 0–5 min 10% B, 5–10 min 10–30% B, 10.1–15 min 0% B; detection: amperometric detector with gold WE, Pt CE and Ag/AgCl RE, 35 °C; waveform: see Fig. 5 (3) with E2 = 0.25 V