Study on recovery of plant fragments from adhesive sheet and tape in forensic examination

Abstract

 Forensic samples may include small plant fragments collected as trace evidence that are examined by microscopy and DNA analysis. These fragments are often recovered on adhesive tapes or sheets; as such, recovery must be carried out carefully so that important morphological features, including thorns or trichomes, are not destroyed. In this study, we investigated the use of organic solvents for the recovery of small plant fragments from adhesive tapes and sheets. Particularly, we examined the influence of the solvent and of the adhesive compound on the DNA analyses. Therefore, our goal was to determine an appropriate recovery method for small plant fragments that did not have a negative impact on critical forensic analyses.

 Plant samples, including seeds and leaves, were attached to adhesive sheets or tapes and recovered with solvents such as water and organic solvents. The extent of recovery and the influence of the adhesive compound and solvent on the subsequent DNA analyses were examined. After the immersion of plant samples in the solvent to detach them from the adhesive compound, DNA extraction and polymerase chain reaction (PCR) amplification were performed.

 Among our findings, we determined that plant samples on most types of adhesive sheets can be recovered with tweezers alone and are appropriate for microscopic evaluation and DNA analysis. Organic solvents were used to recover samples attached to sheets with strong adhesives. This method had no discernible impact on DNA extraction or the subsequent PCR analyses. Thus, we concluded that small plant fragments attached to adhesive sheets or tapes can be recovered for forensic examination with a variety of methods, including the use of organic solvents.