کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1199771 1493561 2014 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Insight into the stability of poly(diallydimethylammoniumchloride) and polybrene poly cationic coatings in capillary electrophoresis
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آنالیزی یا شیمی تجزیه
پیش نمایش صفحه اول مقاله
Insight into the stability of poly(diallydimethylammoniumchloride) and polybrene poly cationic coatings in capillary electrophoresis
چکیده انگلیسی


• Higher molecular weight polycations forms more stable coatings.
• Adsorbed polycation coatings are less stable at high pH.
• Instability was caused by surface catalyzed alkaline conversion of quaternary amines.
• Successive multiple ionic layer coatings show greater alkaline stability by distancing the polycation from the surface.

Polycationic polymers are widely used in capillary electrophoresis (CE) as surface coatings to prevent protein adsorption and control electroosmotic flow (EOF). Such semi-permanent coatings are formed by flushing the capillary with a quaternary amine-based polymer such as poly(diallydimethylammonium chloride) (PDADMAC) or polybrene. Compared to covalent capillary coatings, the claimed advantages of adsorptive polycation coatings are their simple preparation and that they are not limited to the pH 2–8 range as are covalent coatings. However, while the latter is commonly claimed, few studies have demonstrated the stability of polycationic coatings at extreme pH. Herein PDADMAC and polybrene are studied as model cationic coatings. PDADMAC with higher molecular weight (M.W.) demonstrated higher EOF stability at pH 9.5, with PDADMAC of M.W. less than 200,000 being unstable at pH 9.5. X-ray photoelectron spectroscopy (XPS) shows that the quaternary amines of PDADMAC and polybrene were slowly converted to tertiary amines in alkaline solution and more rapidly when adsorbed on a silica surface. The degraded polycation deprotonated at pH >7, resulting in loss of polymer from the surface and diminishing EOF. Successive multiple ionic layer (SMIL) coatings show greater alkaline stability by distancing the polycation from the surface. Separations of inorganic anions at pH 9.5 illustrate the degradation behavior and enhanced stability of higher M.W. polycationic coatings.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Chromatography A - Volume 1365, 24 October 2014, Pages 226–233
نویسندگان
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