title: Development of normal phase-high performance liquid chromatography-atmospherical pressure chemical ionization-mass spectrometry method for the study of 6,6'-bis-(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-benzo[1,2,4]-triazin-3-yl)-[2,2']-bipyridine hydrolytic degradation.
abstract: In the field of nuclear waste management, the 6,6'-bis-(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-benzo[1,2,4]-triazin-3-yl)-[2,2']-bipyridine (CyMe(4)BTBP) is a polycyclic N-based molecule eligible to remove actinides from spent nuclear fuel by liquid-liquid extraction processes. In such processes, the organic phase containing the extracting molecules will undergo hydrolysis and radiolysis, involving degradation products. The purpose of this work was to develop a normal phase chromatography (NP-HPLC) coupled to atmospherical pressure chemical ionisation-mass spectrometry (APCI-MS) method to separate and identify degradation products of CyMe(4)BTBP dissolved in octanol, submitted to HNO(3) hydrolysis. 1 mol L(-1) HNO(3) hydrolysis conditions were used regarding the selective actinides extraction (SANEX) process, while 3 mol L(-1) HNO(3) conditions were applied for the group actinide extraction (GANEX) process. The first step consisted in optimizing the chromatographic separation conditions using a diode array detection (DAD). Retention behavior of a non hydrolyzed mixture of N,N'-dimethyl-N,N'-dioctyl-hexyloxyethyl-malonamide (DMDOHEMA), a malonamide used in the SANEX process to increase the kinetic of extraction, and CyMe(4)BTBP were investigated on diol-, cyano-, and amino-bonded stationary phases using different mobile phase compositions. These latter were hexane with different polar modifiers, i.e. dioxane, isopropanol, ethanol and methylene chloride/methanol. The different retention processes in NP-HPLC were highlighted when using various stationary and mobile phases. The second step was the setting-up of the NP-HPLC-APCI-MS coupling and the use of the low-energy collision dissociation tandem mass spectrometry (CID-MS/MS) of the precursor protonated molecules that allowed the separation and the characterization of the main hydrolytic CyMe(4)BTBP degradation product under a 3 mol L(-1) HNO(3) concentration. Investigation of the CID-MS/MS fragmentation pattern was used to suggest the potential ways leading to this hydrolysis degradation product. This NP-HPLC-APCI-MS method development is described for the first time for the CyMe(4)BTBP and should provide separation methods regarding the analysis of polycyclic N-based extracting molecules and more generally for the investigation of the organic phase coming from liquid-liquid extraction processes used in nuclear fuel reprocessing.
authors.affiliation: CEA, DEN, SECR, Laboratoire de Spéciation des Radionucléides et des Molécules, F-91191 Gif-sur-Yvette, France.
authors.forename: Grégory
authors.initials: G
authors.lastname: Nicolas
authors.forename: Christopher K
authors.initials: CK
authors.lastname: Jankowski
authors.forename: Christine
authors.initials: C
authors.lastname: Lucas-Lamouroux
authors.forename: Carole
authors.initials: C
authors.lastname: Bresson
mesh_terms: D015082:2,2'-Dipyridyl / Q000737:chemistry; D000438:Alcohols / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D013058:Mass Spectrometry / Q000379:methods*; D011725:Pyridines / Q000737:chemistry*; D011850:Radioactive Waste; D014227:Triazines / Q000737:chemistry*
chemical_list: D000438:Alcohols; D011725:Pyridines; D011850:Radioactive Waste; D014227:Triazines; D015082:2,2'-Dipyridyl