Table 2.
Data quality level for ex situ XRF measurements of Cu, Zn, and Pb determined by comparison with the confirmatory chemical analysis (log10 transformed data)
| Element | r 2 | RSD (%)a | Slope (95 % CI) |
Intercept (95 % CI) |
Data quality level |
|---|---|---|---|---|---|
| Cu | 0.99 | 9 | 1.00 (0.95–1.05) |
0.10 (−0.01–0.21) |
Definitive |
| Zn | 0.99 | 9 | 0.96 (0.91–1.01) |
0.17 (0.04–0.30) |
Definitive |
| Pb | 0.88 | 8 | 0.73 (0.60–0.86) |
0.50 (0.30–0.71) |
Quantitative screening |
CI confidence interval
aAverage RSD of all triplicate XRF measurements