MATRIX EFFECTS IN MEMBRANE INTRODUCTION MASS-SPECTROMETRY .1. EFFECT OF POLY(ETHYLENE GLYCOL) ON PERMEATION RATE OF 1-OCTANOL THROUGH SILICONE-RUBBER MEMBRANE

Simple flow-through capillary membrane interface, suitable for direct measurement of organic compounds in aqueous samples, has been built an d its function verified on aqueous solution of 1-octanol. Optimization of experimental conditions involving the adjustment of ion source and inlet transfer line temperatures and the modification of sample solut ion flow rate resulted in short response time (lower than 1 min), high stability of measured signal and high sensitivity toward 1-octanol. P ossible matrix effects of poly(ethylene glycol) (PEG) on the permeatio n rate of 1-octanol were studied. Both adsorption of PEG on the inner membrane surface and formation of PEG-octanol complexes were recognize d as important factors decreasing the measured signal. An attempt to e stimate the PEG-octanol binding ratio from available experimental data was made.