OneAdsorption characteristics of LPS
LPS (lipopolysaccharide) multimers in aqueous solution, because the hydrophilic O-specific polysaccharide chain is located on the outside of the polymer, so it is easy to adsorb with hydrophobic substances, especially in various plastics and glass containers in experiments.
Asbestos, activated carbon, and charged membranes (charged microporous membranes) can adsorb LPS non-specifically. Therefore, in the pharmaceutical industry, endotoxins can be removed from pharmaceuticals and pharmaceutical raw materials by using this property.
The acidic LPS obtained directly after electrodialysis are neutralized by various bases to obtain different LPS salts. Their solubility in water varies greatly. The solubility of R-LPS's triethylamine salt in water can reach 20 mg ml, forming a clear, non-viscous solution. The solubility of triethylamine salt in S-LPS can be as high as 400 mg ml. So far, the solubility of LPS triethylethylamine or tetraethylethylamine salt in water is the largest, the solubility of LPS potassium salt is slightly higher than that of sodium salt and lower than that of triethylamine salt, and the solubility of LPS pyridine salt and ammonium salt is lower than that of LPS sodium salt, and the solubility of LPS bivalent cationic salts such as calcium, magnesium salt and organic salt are extremely low, of which LPS magnesium salt is often insoluble.
The solubility properties of various S-LPS salts in commonly used physiological buffer solutions are similar to their solubility in double distilled water, with LPS having the highest solubility of triethylamine salts and LPS bivalent cationic salts having the lowest solubility. R-LPS salts, on the other hand, are generally insoluble in physiological buffer solutions. In addition, the addition of sufficient bivalent cation can completely precipitate R-LPS from the solution. R-LPS sodium salt is more likely to be precipitated by Ca2+ and Mg2+ than triethylamine salt. The formation of aggregates with different degrees between LPS molecules determines the different dissolution characteristics and characteristic precipitation coefficients (S) of various salts.