Directly heated high surface area solid phase microextraction sampler for rapid field forensic analyses.
A high-surface area solid phase microextraction (HSA-SPME) sampler is described for dynamic sampling at high air velocities (up to several hundred centimeters per second). The sampling device consists of a thin wire coated with carboxen/polydimethylsiloxane (carboxen/PDMS) material, wound in the annular space between two concentric glass tubes, providing a large trapping surface from which analytes may then be thermally desorbed with little power consumption upon resistive heating of the wire. Desorbed analytes are focused and reconcentrated on a microtrap that is subsequently resistively heated to introduce analytes for GC or GC/MS analysis. Benzene, toluene, ethylbenzene, and xylenes (BTEX) included in a 39-component toxic organics (TO-14) gas mixture were used to evaluate the efficiency of the HSA-SPME sampler. Quantitation of trace-level BTEX compounds present during weapons cleaning was completed using stepwise calibration. Detection limits of 0.2-6.9 pptr(v) were observed for these analytes using single ion monitoring GC/MS analysis, and an improvement in sensitivity of several orders of magnitude was achieved when compared to standard dynamic flow SPME with a commercially available 10 mm carboxen/PDMS fiber. The potential for rapid analyte uptake and improved sensitivity using the HSA-SPME design will make it possible to rapidly collect and analyze VOC samples in field settings using a portable hand-held pump and a small, low power GC/MS instrument. This system will be especially useful for situations involving forensics, public safety, and military defensive or intelligence needs where rapid, sensitive detection of airborne analytes is required.
Counterterrorism and Forensic Science Research Unit, FBI Academy, Building 12, Quantico, Virginia 22135, USA.
Scott A
SA
Ramsey
Robert V
RV
Mustacich
Philip A
PA
Smith
Gary L
GL
Hook
Brian A
BA
Eckenrode
D001554:Benzene / Q000032:analysis / Q000302:isolation & purification; D001555:Benzene Derivatives / Q000032:analysis / Q000302:isolation & purification; D053834:Explosive Agents / Q000032:analysis* / Q000302:isolation & purification; D044707:Forensic Sciences / Q000379:methods*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D052617:Solid Phase Microextraction / Q000379:methods*; D014050:Toluene / Q000032:analysis / Q000302:isolation & purification; D014992:Xylenes / Q000032:analysis / Q000302:isolation & purification
D001555:Benzene Derivatives; D053834:Explosive Agents; D014992:Xylenes; D014050:Toluene; D001554:Benzene; C004912:ethylbenzene