A membrane inlet system equipped with a piezoelectric lock for introduction of gaseous samples into a mass-spectrometer

Abstract

The design of a membrane inlet system, which is equipped with a metal-sealed piezoelectric vacuum lock, for introducing samples into a mass spectrometer, is described. The membrane interface is characterized by a selective permeability for volatile target compounds and allows their detection in air with a high sensitivity in a proximate measurement mode using automated portable or mobile mass spectrometers. The system provides short instrument response times (∼1 s) owing to the use of a thin membrane material (tens of microns) and excludes hazardous consequences of a possible destruction of the membrane. The inlet system is controlled via application of voltage to the lock, thus enabling blocking of the gas flow that is supplied to the instrument within several hundredth parts of a second. Testing results are presented.