Emily C. Lennert
tape lift, chemical threat agents, sample collection, acetyl fentanyl
Brady, K.; Stilley, B.; Olds, M.; O’Neill, T.; Egan, J.; Durnal, E. Tape lift sampling of chemical threat agents. Journal of Forensic Sciences. 2017, 62(4), 1015-1021.
The opinions expressed in this review are an interpretation of the research presented in the article. These opinions are those of the summation author and do not necessarily represent the position of the University of Central Florida or of the authors of the original article.
Commercial-off-the-shelf (COTS) products may be useful for law enforcement agencies by providing low cost alternatives for sampling of chemical threat agents, such as acetyl fentanyl, allyl alcohol, disulfoton, and more. The authors of this study evaluated five COTS products for the collection of 14 select chemicals. The study was divided into three phases. The first phase was COTS product selection, followed by the evaluation of COTS product and chemical analytical compatibility, and finally the evaluation of chemical uptake by COTS products.
Five COTS were selected for this study from a pool of eight possible COTS products. Materials that were selected included duct tape, print lifters, command strips, pore strips, and silly putty. Next products were evaluated for possible interferences and recovery of chemicals. Fourteen chemicals were selected and are listed in Table 1 within the study. Blank and spiked samples were prepared for each product to determine whether interferences were present that would affect the identification of target analytes, as well as to determine if the product would degrade the chemicals. Spiked solutions were prepared and applied to the products in a Z shape to ensure coverage of the product with the chemical targets. Samples were allowed to evaporate and then extracted in acetone and methanol following the extraction scheme shown in Figure 1 within the study. Sample extracts were analyzed by GC-MS and LC-MS/MS.
No COTS tape samples showed interferences that would have led to false positive identifications of target chemicals. Although, the results indicated that the matrix of several tape products may have hindered the quantitation of analytes by LC-MS/MS. The average percent recovery for each chemical and each product is given in Table 3 within the study. No recovery of allyl alcohol and methyl acrylonitrile for any product was reported. This was likely due to the volatile nature of the chemicals. Isobutyronitrile was only recovered by silly putty, duct tape, and one pore strip replicate. Isobutyronitrile is also volatile, which likely accounted for its low recovery. Overall, duct tape showed the highest recovery for all chemical targets, while silly putty had the lowest recoveries.
Products were then evaluated for their uptake of chemicals from three surfaces: glass, tile, and plastic. Each surface was cut into 2” x 2” pieces and cleaned prior to spiking of the surface. Samples were prepared in triplicate. Each product was tested on each surface, then the products were extracted and analyzed by GC-MS and LC-MS/MS. Allyl alcohol, methyl acrylonitrile, and isobutyronitrile were not recovered by any product for samples recovered from glass and tile. However, trace levels were recovered from plastic, likely due to its slightly porous nature. All other chemicals were detected on all surfaces, with the exception of several chemicals on print lifters taken from plastic: disulfoton, parathion, and chlorfenvinphos. Overall, duct tape had the best recoveries across all surface types, followed by print lifters.
- Duct tape was shown to be the best COTS product for tape lifting of chemical threat agents.
- Plastic surfaces, which are slightly porous, may provide the best recoveries for sampling with COTS tape lifting products.
COTS products may provide a low cost sampling option for investigators.
Duct tape may be a useful, low cost option for the sampling of chemical threat agents.