Vitamin B12 [BSA]

Capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC) with sodium dodecyl sulfate (SDS) as an anionic carrier were applied to the analysis of nine principal components of eye lotion. Simultaneous separation of these components except cyanocobalamin (VB12), which has the same migration time with that of electroosmotic flow, was achieved by CZE using a 72 cm x 50 mu m i.d. fused silica capillary tube filled with 20 mM borate buffer (pH 10) at 25 kV DC voltage with UV detection at 200 nm. Under these conditions, the peak of chondroitin sulfate (CS) was overlapped with that of aspartic acid in case the latter was contained in the sample as a co-existing component. However, when pH was decreased to 9, CS was separated from other components and also from aspartic acid, and gave a more shapely peak. VB12 could be separated from other components by MEKC with 20 mM borate buffer (pH 10) containing 40 mM SDS. The applicability to the determination of nine principal components of eye lotion is demonstrated.

Activated carbon spheres (ACSs) and carbon micro-nanoparticles derived from nickel (Ni)-doped phenolic beads (similar to 0.8 mm) were synthesized as efficient adsorbents for vitamin B-12 (VB12). Ni was incorporated in an intermediate step during a suspension polymerization. ACSs were synthesized by the carbonization and activation of Ni-doped polymeric beads. Carbon micro-nanoparticles (average size similar to 200 nm) were synthesized by milling polymeric beads followed by carbonization and activation. Adsorption tests were carried out under both batch and dynamic (flow) conditions. The latter tests were carried out in a specially designed and fabricated micro-column packed with carbon micro-nanoparticies. The adsorption loading of VB12 on the adsorbents was determined to be similar to 300 mg/g, corresponding to an aqueous phase concentration of 500 ppm, which is comparable to or larger than the literature data. The method of in situ synthesis of metal incorporated carbon micro-nanoadsorbents and their use in a micro-column under the flow conditions has much potential for bio- and pharmaceutical separation and purification applications. (C) 2012 Elsevier B.V. All rights reserved.