Oxidation–reduction reactions of simple hydroxamic acids and plutonium(IV) ions in nitric acid

Simple hydroxamic acids such as formo- and aceto-hydroxamic acids have been proposed as suitable reagents for the separation of either Pu and/or Np from U in modified or single cycle Purex based solvent extraction processes designed to meet the emerging requirements of advanced fuel cycles. The stability of these hydroxamic acids is dominated by their decomposition through acid hydrolysis. Kinetic studies of the acid hydrolysis of formo- and aceto-hydroxamic acids are reported in the absence and the presence of Pu(IV) ions. The slow reduction of these plutonium(IV) hydroxamate complexes to Pu(III) aquo-ions has been characterised by spectrophotometry and cyclic voltammetry. The reductions of Pu(IV) in the presence of FHA and AHA are consistent with a mechanism in which free hydroxamic acid in solution is hydrolysed whilst Pu(IV) ions remain fully complexed to hydroxamate ligands; then at some point close to a 1 : 1 Pu(IV) : XHA ratio, some free Pu4+ is released from the complex and reduction is initiated. Electrochemical and kinetic data suggest that the reductant is the hydroxamic acid rather than the hydroxylamine.

A preliminary study of the analysis of Cannabis by supercritical fluid chromatography with atmospheric pressure chemical ionisation mass spectroscopic detection

A rapid method is described for the analysis of Cannabis products by supercritical fluid chromatography (SFC) coupled to atmospheric pressure chemical ionization-mass spectroscopic (APCI-MS) detection. The method had a shorter analysis time than GC-MS methods, without the need for derivatization prior to analysis. It was also faster than HPLC methods, with better resolution and definitive identification. Linearity of detector response to cannabidiol, delta 8-tetrahydrocannabinol, delta 9-tetrahydrocannabinol and cannabinol was established, the detection limits for mass on column being 0.55 ng, 1.20 ng, 0.69 ng and 2.10 ng respectively. The technique offers a means by which Cannabis products can be definitively identified in a single chromatographic run. Application to casework samples is described.