ENHANCED EXTRACTION OF PHENOBARBITAL FROM SERUM WITH A DESIGNED ARTIFICIAL RECEPTOR

The primary goal of this work was to determine whether artificial rece ptors that function on the basis of molecular recognition have analyti cal capabilities. As an example of such a receptor, we have chosen one directed toward barbiturates. Chloroform enriched with this artificia l receptor (1 mM) can extract more than 90% of the phenobarbital from a 20 mu M phenobarbital solution in human control serum using a volume ratio (organic/serum) as small, as 0.5. In the absence of this recept or, the volume ratio must be greater than 10 to achieve similar extrac tion efficiencies. In addition to volume ratio, the role of pH, recept or concentration, and solvent type are discussed. The experimental res ults are found to be in good agreement with predictions based on chemi cal equilibria. Through the use of this and other similar receptors, t he amount of organic solvent used in extractions can be minimized.