Table 1.
Level of factors in the CCD used for the optimization of separation parameters, sheath liquid parameters, and spray chamber parameters in MEKC-MS.
| MEKC parameters | ||||||
|---|---|---|---|---|---|---|
| Level | F1: pH | F2: [Surfactant] (mM) | F3: [NH4OAc] (mM) | F4: Voltage (kV) | F5: Temperature (°C) | F6: Neb. Pres. (psi) |
| −1 | 10.00 | 15.0 | 15.0 | 10 | 16.0 | 3 |
| 0 | 10.75 | 22.5 | 25.0 | 15 | 20.5 | 4 |
| +1 | 11.50 | 30.0 | 35.0 | 20 | 25.0 | 5 |
| Sheath liquid parameters |
Spray chamber parameters |
||||||
|---|---|---|---|---|---|---|---|
| Level | F1: %MeOH (v/v) | F2: pH | F3: [NH4OAc] (mM) | Level | F1: DGFa (L/min) | F2: DGTb (°C) | |
| −1 | 20 | 6.00 | 5.0 | −1 | 4.0 | 150 | |
| 0 | 50 | 7.25 | 22.5 | 0 | 5.0 | 200 | |
| +1 | 80 | 8.50 | 40.0 | +1 | 6.0 | 250 | |
a
DGF: drying gas flow rate.
b
DGT: drying gas temperature.