Table 2.
Linear regression parameters for relaxometry and spectrophotometry calibration curves.
| Ion | Slopea | Intercepta | r 2 | |
|---|---|---|---|---|
| Spinlockb | Ni2+ | 572 ± 3 | 0.404 ± 0.001 | 0.9998 |
| Cu2+ | 1491 ± 8 | 0.402 ± 0.002 | 0.9998 | |
| Cr3+ | 7370 ± 158 | 0.420 ± 0.010 | 0.9978 | |
| Mn2+ | 31487 ± 282 | 0.405 ± 0.003 | 0.9993 | |
|
| ||||
| UNMRb | Ni2+ | 632 ± 4 | 10.4 ± 0.1 | 0.9998 |
| Cu2+ | 1141 ± 8 | 10.0 ± 0.3 | 0.9996 | |
| Cr3+ | 9570 ± 130 | 13.4 ± 0.2 | 0.9993 | |
| Mn2+ | 28517 ± 294 | 10.3 ± 0.3 | 0.9992 | |
|
| ||||
| SPc | Ni2+ | 5.01 ± 0.01 | 0.0004 ± 0.0003 | 0.9999 |
| Cu2+ | 12.45 ± 0.04 | 0.005 ± 0.002 | 0.9999 | |
| Cr3+ | 16.28 ± 0.29 | 0.0365 ± 0.0513 | 0.9991 | |
aMean ± SD (n = 7); b R 2 = intercept + slope[ion], where R 2 (s−1) is the inverse of T 2 and the ion concentration is given in mol L−1; c A(λ 810 nm) = intercept + slope[ion], where A is the absorbance in 810, 422, and 394 nm for Cu2+, Cr3+, and Ni2+, respectively, and the ion concentration is given in mol L−1.