Fig. 7.

The combined effect of the variation of pressure and voltage for the simultaneous separation of nine KP metabolites. 1. THIO (850 μM), 2. TRP (7.5 μM), 3. KYN (15 μM), 4. HKYN (25 μM), 5. KA (8.34 μM), 6. HAA (32.5 μM), 7. PA (30 μM), 8. AA (12.5 μM), 9. XA (40 μM), 10. QA (150 μM). Mobile phase: 15 mM (NH4)2CO3, pH 8.25. The applied voltage of 18 and 20 kV and internal pressure 100 mbar and 950 mbar, the external pressure of 2.0 bar were used. Other conditions and parameters are the same as described in Fig. 3, except a longer column of 150 cm length was used.