Table 2 The data of 15% ( v/v ) MeOH with calculation method
From: pKa determination of oxysophocarpine by reversed - phase high performance liquid chromatography
No. | pH of mobile phase | t R | Tailing factor of peak | k | pH ( i+ 1)–pH i | k ( i+ 1) – k i | (k ( i+ 1) – k i ) / (pH ( i+ 1)–pH i ) |
|---|---|---|---|---|---|---|---|
1 | 2.2 | 8.091 | 1.305 | 1.804 | - | - | - |
2 | 2.5 | 8.320 | 1.294 | 1.883 | 0.3 | 0.079 | 0.264 |
3 | 3.9 | 8.733 | 1.338 | 2.026 | 1.4 | 0.143 | 0.102 |
4 | 5.0 | 9.881 | 1.665 | 2.424 | 1.1 | 0.398 | 0.362 |
5 | 6.0 | 15.076 | 3.319 | 4.224 | 1.0 | 1.800 | 1.800 |
6 | 7.0 | 25.871 | 5.777 | 7.964 | 1.0 | 3.740 | 3.740 |
7 | 7.6 | 29.759 | 5.792 | 9.312 | 0.6 | 1.348 | 2.247 |
8 | 7.9 | 30.805 | 5.834 | 9.674 | 0.3 | 0.362 | 1.207 |
9 | 8.9 | 31.549 | 5.826 | 9.932 | 1.0 | 0.258 | 0.258 |