Enhancing capabilities of aspiration-type Ion Mobility Spectrometer using a Pulsed Sampling System and a heated transfer line

An aspiration-type Ion Mobility Spectrometer (IMS) was connected to an in-house developed Pulsed Sampling System (PSS) through a heated capillary column acting as transfer line, after being modified to a closed loop IMS device. Performance of the whole system was evaluated using acetone gas standards in the concentration range of 200-2000 ppb. Tests were carried out using an in-house developed chemical environment generator for producing acetone concentrations. The system presented long-term stability, linearity, sensitivity and low minimum detectable level; less than 286 ppb for acetone with a closed loop that circulates 1300 mL/min of purified air. Repeatability (RSD) was less than 15% for all concentrations. All data were produced in dry atmosphere inside the IMS; presence of moisture (e.g. when saturation of molecular sieves occurs) seems to severely reduce performance.