Table 3 Matrix effects, absolute recovery and process efficiency for Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD), using dried oral fluid spots (DOFS) and weak anion exchange and salt (WAX-S) tips extraction
| Drug |
Matrix Effects* (%) |
CV (%) | Absolute Recovery* (%) | CV |
Process Efficiency * (%) |
CV (%) |
|---|---|---|---|---|---|---|
| THC (N = 10) | ||||||
| DOFS | ||||||
| Low (12 ng/mL) | 98.7 | 15.6 | 23.8 | 14.2 | 23.5 | 19.3 |
| High (50 ng/mL) | 80.3 | 17.3 | 25.3 | 13.9 | 20.3 | 20.7 |
| WAX-S tips | ||||||
| Low (12 ng/mL) | 92.4 | 6.8 | 90.7 | 6.2 | 83.8 | 4.0 |
| CBD (N = 10) | ||||||
| DOFS | ||||||
| Low (12 ng/mL) | 75.2 | 18.5 | 24.8 | 18.0 | 18.6 | 23.9 |
| High (50 ng/mL) | 76.4 | 18.7 | 28.7 | 17.6 | 21.9 | 23.8 |
| WAX-S tips | ||||||
| Low (12 ng/mL) | 87.5 | 7.0 | 93.2 | 8.7 | 81.6 | 5.5 |