Table 2. Method Validation Parameters for the Analysis of DPG, DTG, and TPG in Human Urinea.
| DPG | DTG | TPG | |
|---|---|---|---|
| R in solvent | 0.9999 | 0.9995 | 0.9920 |
| Slope in solvent | 0.18 | 0.10 | 0.63 |
| R in urine matrix | 0.9999 | 0.9998 | 0.9949 |
| Slope in urine matrix | 0.15 | 0.09 | 0.42 |
| LOD (ng/mL) | 0.02 | 0.02 | 0.002 |
| LOQ (ng/mL) | 0.05 | 0.05 | 0.005 |
| absolute recovery % | 44.1 | 49.0 | 99.2 |
| ME % | –13.6 | –15.0 | –33.1 |
| Spike-Recovery%, n = 3 | |||
| 1 ng/mL | 107 ± 2 | 101 ± 3 | 85.7 ± 0.8 |
| 5 ng/mL | 102 ± 1 | 101 ± 1 | 75.3 ± 0.7 |
| 10 ng/mL | 111 ± 2 | 108 ± 1 | 78.4 ± 0.7 |
| 20 ng/mL | 106 ± 1 | 104 ± 4 | 76.5 ± 1.7 |
| Intra-Day CV %, n = 3 | |||
| 1 ng/mL | 1.94 | 2.96 | 0.91 |
| 5 ng/mL | 1.11 | 1.27 | 0.93 |
| 10 ng/mL | 2.08 | 0.93 | 0.88 |
| 20 ng/mL | 0.47 | 3.90 | 2.26 |
| Inter-Day CV %, n = 3 | |||
| 1 ng/mL | 2.79 | 0.86 | 1.29 |
| 5 ng/mL | 1.03 | 0.66 | 0.82 |
| 10 ng/mL | 3.02 | 2.67 | 3.31 |
| 20 ng/mL | 3.76 | 2.65 | 2.96 |
| Variation in Concentration % after Three Freeze–Thaw Cycles (Mean ± SD), n = 3 | |||
| 1 ng/mL | –8.27 ± 10.0 | –3.71 ± 4.50 | –13.5 ± 4.8 |
| 5 ng/mL | 2.99 ± 1.37 | 1.21 ± 2.28 | 0.82 ± 4.58 |
| 20 ng/mL | 1.05 ± 17.8 | 0.97 ± 17.6 | 1.39 ± 20.6 |
| Variation in Concentration % after Holding Urine at Room Temperature Overnight (Mean ± SD), n = 3 | |||
| 1 ng/mL | –10.5 ± 14.6 | –8.77 ± 13.9 | –19.2 ± 9.6 |
| 5 ng/mL | –5.99 ± 2.74 | –3.32 ± 1.05 | –11.4 ± 2.2 |
| 20 ng/mL | –12.3 ± 3.8 | –12.2 ± 3.7 | –11.3 ± 5.7 |
| Variation in Concentration % after Holding Urine Extract at Room Temperature Overnight (Mean ± SD), n = 3 | |||
| 1 ng/mL | –25.6 ± 3.1 | –24.3 ± 2.4 | –26.8 ± 1.0 |
| 5 ng/mL | –12.4 ± 1.7 | –10.7 ± 5.5 | –10.7 ± 1.7 |
| 20 ng/mL | –2.11 ± 21.4 | –6.05 ± 13.0 | –1.62 ± 18.0 |
a
Abbreviations: LOD, limit of detection; LOQ, limit of quantification; ME, matrix effect; CV, coefficient of variation; and R, regression coefficient.