A new thermal desorption solid-phase microextraction system for hand-held ion mobility spectrometry

Abstract

In this paper a new prototype of solid phase microextraction–ion mobility spectrometry (SPME–IMS) system was developed to effectively couple the extraction efficiency of SPME with the detection capability of IMS. The main component of this system was the transfer line/desorber, which was a low-thermal-mass (ca. 0.15 g) silicosteel coatings stainless steel tube. The transfer line/desorber was designed to rapidly desorb and transfer the analytes extracted by SPME to IMS. A custom-made temperature controller with a proportional–integral–differential (PID) was used to maintain the temperature of the transfer line/desorber stable and avoid overheating or oscillating. The low thermal mass of this interface allowed it to be rapidly heated and cooled with much less electrical power and could substantially reduce the demand for high capacity batteries. The operational characteristics of this system were demonstrated through the analysis of camphor vapour. The precision of reduced mobility and the peak amplitude of camphor were good (R.S.D. 0.62%, n = 10; R.S.D. 2.5%, n = 10, respectively). SPME–IMS system was also shown to be capable of on-site measurement by monitoring the biogenic volatile organic compounds (BVOCs) emitted from eucalyptus citriodora leaves. In addition, this system was applied to quantitation of diazepam and cocaine in aqueous solution. Limits of detection were 10 ng/mL for diazepam and 50 ng/mL for cocaine with the reported experimental conditions. This SPME–IMS system exhibits considerable promise as a robust, simple, rapid, energy-saving fieldable approach for on-site analysis of analytes in various matrix.