Bovine Serum Albumin as Mobile Phase Modif er

BSA is a protein of relative molecular mass 66210, consisting of 581 amino acids in a single chain. It is a relatively acidic protein (isoelectric point 4.7), highly soluble in water, but precipitates from high salt solutions. At pH 7.0 its net charge is —18. Hydrophobic interactions strongly contribute to the affinity of organic solutes for BSA; simultaneous contributions exist from electrostatic interactions, steric effects, hydrogen bonding and charge-transfer processes.

Mobile phases containing this chiral selector have been employed for the resolution of a broad variety of racemic compounds on silanized silica plates. Eluents were prepared by dissolving BSA (Serva, Heidelberg,

FRG), fraction V, pH 5.2 or 7.0, in different buffer systems and then adding the desired amount of 2-propanol. The results suggest the use of acidic eluents to separate N-derivatized amino acids on wettable RP-18W/UV254 (Macherey-Nagel) or RP-18W/F254 (Merck) plates. On the other hand, the resolution of free amino acids increases with increasing eluent pH; in particular, the useful pH range on SIL C18-50/UV254 layers (Macherey-Nagel) is 9-10.

A prerequisite for optical discrimination is the presence of aromatic as well as polar groups in the solute. The existence of stereospecific binding sites on albumin is well known (i.e. tryptophan and warfarin) and it is believed that this binding occurs at a number of relatively defined regions. Two independent non-cooperative types of sites (chiral and achiral) coexist on the protein; the retention mechanism is partially in accord with that proposed on columns packed with immobilized BSA since in TLC albumin is used as a mobile-phase additive.

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Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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