3. Results
The efficacy of each collection technique was evaluated by the quantity of DNA present in each sample and the percent STR profile (alleles obtained/alleles expected × 100) generated by each sample. For each collection technique and substrate type, the DNA quantities were averaged across all three donors. Large standard deviations were observed due to the wide range of DNA quantities deposited by the different donors. The copy paper samples were the only samples collected with the ESDA that demonstrated a statistically significant difference (p < 0.05) in DNA quantity when compared to those collected with dry swabbing ( Table 1). No other samples collected with the ESDA technique demonstrated statistically significant differences in DNA quantity when compared to the samples collected via dry swabbing. When compared to the fingerprint samples collected with the destructive substrate cutting technique, the ESDA samples collected from cotton paper demonstrated a statistically significant increase in DNA quantity; however, when collecting samples from newspaper, the ESDA collection technique resulted in a statistically significant decrease in DNA quantity when compared to substrate cutting. The samples collected with the dry swabbing technique from resume paper, cotton paper, and currency displayed statistically significant increases in DNA quantity when compared to those collected with the destructive collection techniques; however, when collecting samples from newspaper, the dry swabbing collection technique resulted in a statistically significant decrease in DNA quantity when compared to substrate cutting.