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.
Ramsey
Scott A
SA
Counterterrorism and Forensic Science Research Unit, FBI Academy, Building 12, Quantico, Virginia 22135, USA.
Mustacich
Robert V
RV
Smith
Philip A
PA
Hook
Gary L
GL
Eckenrode
Brian A
BA
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