Surface modification of chromatography adsorbents by low temperature low pressure plasma

摘要: Abstract In this study we show how low temperature glow discharge plasma can be used to prepare bi-layered chromatography adsorbents with non-adsorptive exteriors. The commercial strong anion exchange expanded bed matrix, Q HyperZ, was treated plasmas in one of two general ways. Using a purpose-designed rotating reactor, were employed either: (i) remove ligands at or close the exterior surface and replace them polar oxygen containing functions (‘plasma etching oxidation’); (ii) bury same exposed beneath thin polymer coatings polymerization coating’) using appropriate monomers (vinyl acetate, vinyl pyrrolidone, safrole) argon as carrier gas. X-ray photoelectron spectroscopy analysis (first ∼10 nm depth) HyperZ before after various treatments confirmed that substantial changes elemental composition HyperZ's had been inflicted all cases. atomic percent carbon, nitrogen, oxygen, yttrium zirconium observed being air entirely consistent with: removal pendant (trimethylammonium) functions; increased exposure underlying yttrium-stabilised zirconia shell; introduction hydroxyl carbonyl functions. Following (with three tested), levels carbon parallel drops provided clear evidence coats created exteriors adsorbent particles. No size morphology, nor any plasma-induced damage could discerned from scanning electron micrographs, light micrographs measurements particle distributions following 3 h (220 V; 35.8 W L−1) ‘vinyl acetate/argon’ (170 V; 16.5 W L−1) plasmas. Losses bulk chloride capacity enabled effective modification depths within hydrated particles calculated 0.2–1.2 μm, depending on conditions applied. depth induced alteration strongly influenced by power input batch, i.e. dropping increasing batch resulted reduced penetration therefore shallower modification. selectivity ‘surface vs. core’ imparted evaluated static dynamic binding studies employing probes, plasmid DNA, sonicated calf thymus DNA bovine serum albumin. performed 5 g scale (25 g L−1 reactor), highest ‘surface/core’ for subjected 220 V (35.8 W L−1). This treatment removed ∼53% ‘surface’ expense 9.3% loss ‘core’ protein binding. Even more impressive results obtained adsorption conducted (220 V, 3 h) (170 V, 10.5 g (52.5 g L−1 reactor). both treatments: 10% breakthrough capacities modified towards probes dropped very significantly (30–85%); inter-particle cross-linking contraction beds during application native completely eradicated; but performance remained unchanged cf. starting material.