Summary of Difficulties and Advantages of the Three Methods
| Concept | TOC-VCSN | TOC-VWP | HPLC |
|---|---|---|---|
| Maintenance cost | ++ | + | ++++ |
| Validation/method qualification time consumed/year | + | + | + |
| Qualification cost/year | + | + | ++ |
| Analysis standard time (calibration curve + samples) | + | ++ | ++++ |
| Reactants cost | ++ | +++ | ++++ |
| Staff | +++ | +++ | +++ |
| Standard cost/analysis | ++ | +++ | ++++ |
| % obtained recovery (API A′) | 75% | 71% | 69.8% |
| DL (ppm C) | 0.0068 | 0.0002 | 0.0664 |
| QL (ppm C) | 0.0227 | 0.0006 | 0.2215 |
| Method precision (CV %, 1 ppm) | 6.52 | 4.56 | 2.23 |
| Accuracy (% recovery, 1.43 ppm) | 105 | 90 | 100 |
| Accuracy (% recovery, 2.87 ppm) | 109 | 74 | 101 |
| Accuracy (% recovery, 5.70 ppm) | 106 | 95 | 99 |
| Standard required | Universal (potassium phthalate) | Universal | Specific (API) |