Comparison of extraction procedures for radioimmunoassay of human plasma somatostatin

Abstract

Recovery and chromatography profiles of human plasma somatostatin extracted by three different procedures were compared. Extraction of plasma using acid-acetone-ether and octadecylsilyl silica gave comparable recovery (84 +/- 1 and 93 +/- 2%, respectively), which were nearly twofold greater than recovery achieved with the acid-ethanol method (50 +/- 1%, p less than 0.01). Acid-acetone-ether and octadecylsilyl silica extraction eliminated nearly completely immunoreactive material other than somatostatin-14 and -28, whereas the acid-ethanol-ether method did not. Because of its simplicity, octadecylsilyl silica is probably the method of choice for extraction of somatostatin from human plasma.