Calibration of membrane extraction for air analysis

Calibration methods based on the recently developed mathematical model are proposed for air monitoring by membrane extraction. In membrane extraction, analytes permeate through the membrane at a constant rate controlled by the distribution constant and the diffusion coefficient. The principle of the proposed calibration approach is based on either theoretical or experimental determination of both constants at the extraction conditions. A group of selected compounds was employed for the experimental testing, and the results indicated practical feasibility of the approach. On-line determination of partition coefficients and distribution constants was proposed and investigated, producing very promising results. Both approaches to calibration facilitate quantitative monitoring.