Table 1 The experimental field definition for PBD
Variable | Symbol | Low ( −) | High ( +) |
|---|---|---|---|
Micro-drop volume (µL) | Drop volume | 2.0 | 5.0 |
Sample volume (mL) | Sample volume | 1.0 | 8.0 |
Stirring speed (rpm) | Stirring speed | 100 | 1200 |
Extraction temperature (oC) | Temp | 60.0 | 120.0 |
Extraction time (min) | Time | 20 | 60 |
pH | pH | 4.0 | 10.0 |
Ionic strength (g mL−1) | Salt | 0.0 | 0.5 |
Gas flow (mL min−1) | N2 | 0.0 | 4.5 |
Extraction solvent ratio (%) | GLY:EG | Glycerol | Ethylene glycol |