Use of Multivariate Calibration for Plutonium Quantitation by the Pu(III) Spectrophotometric Method

摘要

Two new multivariate calibration methods for using all of the relevant spectral information are applied to the determination of plutonium. The analyte response signal originates from the absorbance spectrum of Pu(III)from 500 to 900 nm. Partial least squares (PLS) regression gives an average absolute error of 0.114 /+-/ 0.108 mg when predicting plutonium content of standards containing 65 to 90 mg total plutonium. PLS uses all of the signal in the spectrum and is a more robust calibration procedure than a method based on absorbances at five wavelengths. Another calibration procedure involving least squares curve fitting (LSCF) fits either the entire spectrum or individual spectral intervals derived from standards to spectra of unknowns. In addition, an arbitrary linear base line can be included. The best LSCF option for the same calibration and test set as used for PLS was the full spectrum (522 to 900 nm) with a linear base-line option. The average absolute error when predicting with LSCF was 0.130 /+-/ 0.092 mg plutonium. LSCF has an advantage over PLS in that the linear base line can account for certain types of interferences that have been observed for this plutonium assay procedure. An example is given. 6 refs., 3 figs., 5 tabs. (ERA citation 13:037022)