Separation of hydrophobic polymer additives by microemulsion electrokinetic chromatography

摘要: Microemulsion electrokinetic chromatography (MEEKC) has been applied to the separation of some phenolic anti-oxidants [Irganox 1024, Irganox 1035, 1076, 1010, 1330, Irgafos 138, 168 and 2,6-di-tert.-butyl-4-methylphenol (BHT)]. Due extremely hydrophobic nature these analytes, they could not be separated using standard MEEKC conditions two alternative approaches were investigated. Using an acidic buffer (phosphate, pH 2.5) effectively suppress electroosmotic flow, addition 2-propanol aqueous phase microemulsion improve partitioning a negative voltage, five analytes in under 10 min was possible. The second approach, basic (borate, 9.2) positive voltage resulted complete resolution all eight analytes. A mixed surfactant system comprising anionic sodium dodecyl sulfate (SDS) neutral Brij 35 used reduce overall charge with it mobility droplets, hence time. optimised consisting 2.25% (w/w) SDS, 0.75% 35, 0.8% n-octane, 6.6% 1-butanol, 25% 64.6% mM borate (pH target baseline 25 min. For found superior micellar every respect. Specifically, solubility better, selectivity more favourable, analysis time shorter efficiency up 72% higher when method. Detection limits from 5.4 26 μg/ml obtained calibration plot linear over than one order magnitude. method determination 1330 1010 polypropylene.