Detection method of presence of biological and/or chemical substances in gaseous medium

摘要

In the present invention, there is disclosed a method of detecting presence of biological and/or chemical substances in gaseous medium wherein the invented method is characterized by measuring resonance frequency of a piezoelectric crystal introduced into the gaseous medium wherein the surface of said piezoelectric crystal is provided with an absorption layer. At the same time, there are also measured changes of the resonance frequency in time whereupon dispersion and spectral density of the resonance frequency of the piezoelectric crystal being introduced into the gaseous medium are derived from the measured characteristic of the resonance frequency in time. Subsequently, mean time of capture of analyzed gas molecules onto the absorption layer is derived from the dispersion and spectral density of the resonance frequency of the piezoelectric crystal being introduced into the gaseous medium. The value of the mean time of capture of analyzed gas molecules onto the absorption layer is then used for more accurate identification of the biological and/or chemical substance being detected.