This report summarizes the development and implementation of a novel sampling device (capillary microextraction of volatiles [CMV]) for ignitable liquid residue (ILR), which was achieved by the Almirall research group at Florida International University.
The versatility of the CMV gives it the potential for field sampling applications when coupled with portable analytical systems. It was successfully tested in sampling volatile compounds produced by explosives, detecting marijuana plants, detecting volatile organic compounds (VOCs) released from amphetamines, analyzing breath samples, sampling organic gunshot residue (OGSR) VOCs, and sampling BTEX (benzene, toluene, ethylbenzene, and the three xylene isomers) compounds in environmental studies. The CMV is a glass capillary tube, 2 centimeters (cm) long by 2 millimeters (mm) wide. It is open at both ends. The tube is designed to fit inside the injection port of a gas chromatograph (GC) that is filled with seven sorbent-coated glass filter strips stacked on top of each other. The sorbent is vinyl-terminated polydimethylsiloxane that has been physically incorporated into a polymer lattice using solgel synthesis. The CMV acts as an active headspace sampling device, with connection to a vacuum pump, enabling continuous airflow through the tube and subsequent adsorption of compounds. Analyte desorption occurs via a thermal separation probe after placing the CMV directly into a GC’s injection port. Previous applications have reported enhanced sensitivity and extraction capabilities for multiple classes of volatile and semi-volatile organic compounds when using CMV compared to traditional sampling techniques such as SPME. Findings are presented from the evaluation of modified existing vt-PDMS sorbent chemistries that were developed to improve CMV extraction capabilities without the need for temperature manipulation at collection. 4 figures and 17 references