Preconcentration and enantiomeric separation of cathinones using capillary electrophoresis.

Identifier:  TFG:1200

Handle: https://hdl.handle.net/20.500.11797/TFG1200

Authors:  Moya Rodríguez, Desirèe

Abstract:
In this work we have focused in the preconcentration and separation of six cathinone compounds (3,4-Dimethylmethcathinone, 4-Methylethylcathinone, ɑ-PVP, Mephedrone, Methylone y 3,4-Methylenedioxypyrovalerone), by using field-amplified sampling injection (FASI), as in-line preconcentration strategy combination with CE. Firstly we have focused in the enantiomeric separation of the analytes and for that different chiral additives were tested by adding them in the background electrolyte (BGE). In particular the best resolution between all the enantiomers was achieved by adding a mixture of two cyclodextrins (CDs), in particular 5 mM of HP-β-CD and 5 mM β-CD. Moreover, the effect of adding different ionic liquids (IL) as 1-octyl-3-methylimidazolium hezafluorophosphate and 1-hexyl-3-methylimidazolium hezafluorophosphate was also evaluated. Secondly, in order to improve the limited sensitivity inherent to CE, we evaluated the use of an in-line electrophoretic preconcentration strategy, in particular FASI for that, different parameters which can have an effect on the preconcentration were tested as the nature and amount of solvent plug or the sample injection conditions. The best results were obtained using an hydrodynamic injection of MeOH/H2O 25/75 as a solvent plug, at 50 mbar during 5 seconds and an electrokinetic injection of the sample dissolved in water, using 13 kV during 5 seconds. Under these conditions the preconcentration factors were found to be +30 kV , 25ºC during 35 minutes.