Development of supercritical fluid chromatography for analysis of TRUEX process solvents. [N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO)]

This report summarizes the work that has been performed at Argonne National Laboratory on the development of an analytical procedure to analyze TRUEX process solvents; these solvents are composed of a bifunctional organophosphorus extractant (octylphenyl-N,N-diisobutylcarbamoylmethylphosphine oxide, O{phi}D(iB)CMPO or simply CMPO) and tributylphosphate (TBP) in either a normal paraffinic hydrocarbon (NPH) or tetrachloroethylene (TCE) diluent. Supercritical fluid chromatography (SFC) was chosen for this analytical technique because it yields a good separation of the components of the TRUEX solvent and is useful at temperatures below the decomposition temperature of CMPO ({approximately}180{degree}C). Discussed are concepts important to using SFC for chromatographical separations and with four different detectors: flame ionization detector (FID), nitrogen/phosphorus detector (NPD), mass spectrometer (MS), and ultraviolet (UV) detector. A comparison of the four detectors for the analysis of CMPO, TBP, and the TRUEX solvents shows that FID is the best for quantitating CMPO, TBP, and the degradation products. The mass spectrometer is the best for identifying unknown impurities and degradation products. Standard procedures based on the results of this study are reported for analysis of CMPO alone, CMPO dissolved in TBP, and the TRUEX-NPH and TRUEX-TCE solvents. 28 refs., 33 figs., 8 tabs.