Table 2.
Validation parameters of elaborated methods.
| Parameter | Direct spectrophotometric method | Spectrophotometric method based on derivatization reaction | HPLC method based on DHLA-CMQT product as precolumn derivatization reaction |
|---|---|---|---|
| Linearity range/μmol L−1 | 50–750 | 1.0–10 | 2.5–50 |
| Equation of calibration curve/x-concentration in mol L−1 | y = 1.6 · 103 x + 1.6 · 10−3 | y = 1.5 · 104 x + 0.4 · 10−3 | y = 4.0 · 107 x − 110.75 |
| Correlation coefficient | 0.999 | 0.999 | 0.997 |
| LOD/μmol L−1 | 1.120 | 0.258 | 0.214 |
| LOQ/μmol L−1 | 37 | 0.784 | 0.647 |
| RSD/% | 0.5 | 3.0 | 2.06 |
| SD | 0.018 | 7 · 10−3 | 0.014 |