Table II. Se speciation in Opuntia tissue by bulk XANES spectroscopy.
Results of the least squares LCF of Se K-edge XANES spectra are shown. Values are percentage contributions ± 3 times the estimated sd determined in the fit. Fractions lower than 3 times the estimated sd were eliminated, and the fit was repeated. Fit errors (residuals) are also provided. SeO32−SeCys, SeCystine, and elemental Se0 were not detected (ND).
| Frozen Ground Opuntia Tissue | SeO42− | Trimethylselenonium | SeMet | Fit Errors (×10−2) |
| Cladode tips | 42 (1) | ND | 58 (1) | 0.11 |
| Pulp | ND | ND | 100 (1) | 0.02 |
| Juice | 2 (1) | ND | 98 (1) | 0.03 |
| Seed | ND | 7 (1) | 93 (1) | 0.02 |