Fig. 4

Optimization of SPE parameters: desorption solvent (a), desorption solvent volume (b), sample pH (c), and extraction time (d). Analytes concentration, 50 µg/L; sample volume, 50 mL; flow rate, 0.83 mL/min; sorbent weight, 6 mg.

Optimization of SPE parameters: desorption solvent (a), desorption solvent volume (b), sample pH (c), and extraction time (d). Analytes concentration, 50 µg/L; sample volume, 50 mL; flow rate, 0.83 mL/min; sorbent weight, 6 mg.