A new extraction of arginine vasopressin from blood: the use of octadecasilyl-silica.

Small columns packed with octadecasilyl-silica were used to extract arginine-vasopressin in femtomole amounts from biological fluids for radioimmunoassay. This method is effective in isolating the peptide from substances in plasma and serum which interfere with its quantitation. Consistent and reproducible results and recoveries > 80% were obtained with this procedure. High pressure liquid chromatography and serial dilution of extracted samples confirm the identity of the extracted product.