Fig. 2.

Optimized separation of a 10-μM multi-phosphonate standard using optimized chromatographic and amperometric parameters, shown after blank subtraction. Column: Thermo Scientific Dionex AS16 (2 × 5 + 2 × 250 mm) at 30 °C; MFC 500 inserted between pulse damper and six-port injection valve; eluents A 15 mM NaOH, B 15 mM NaOH + 400 mM NaOAc; flow rate: 0.3 mL/min; gradient profile: 0–6 min 0% B, 6–18 min 10–100% B, 18–21 min 100% B, 21.1–22 min 0% B, post run: 9 min with 100% eluent A at 0.6 mL/min; detection: amperometric detector with gold WE, Pt CE and Ag/AgCl RE, 35 °C; waveform: see Fig. 5 (3); injection volume: 50 μL; 10 μM of (1) AMPA, (2) glyphosate, (3) IDMP, (4) ATMP, (5) EDTMP, and (6) DTPMP