Table 1.
Quality control
| Cd | Pb | |
|---|---|---|
| Blank sample | 1 M HNO3 | 1 M HNO3 |
| Certified reference material (1) | INCT-TL-1 (Tea leaves) | INCT-TL-1 (Tea leaves) |
| Certified reference material (2) | INCT-MPH-2 (Mixed Polish herbs) | INCT-MPH-2 (Mixed Polish herbs) |
| Certified element concentration in CRM 1 | ||
| Certified, mg kg−1 | 0.030 | 1.78 |
| Observed, mg kg−1 | 0.029 | 1.76 |
| Recovery rate, % | 98 | 99 |
| Certified element concentration in CRM 2 | ||
| Certified, mg kg−1 | 0.199 | 2.16 |
| Observed, mg kg−1 | 0.189 | 2.22 |
| Recovery rate, % | 95 | 103 |
| Precision, % | 6.04 | 6.07 |
| Replicates | 3 | 3 |