Table 1 The experimental design
From: Comparison between various DNA sterilization procedures applied in forensic analysis
Sr. No | Experiments | Details |
|---|---|---|
1 | Disinfecting the working area surfaces and instruments with 85% ethanol solution | This experiment was done to show the effectiveness of applying 85% ethanol solution to surfaces. Method: This is a screening test; therefore, all the surfaces were swabbed for touch DNA, then 85% ethanol solution was applied. Finally, the surfaces were swabbed. Number of samples collected: a total of 12 replicate cotton swabs for pre- and post-cleaning of the thermomixer surfaces. |
2 | Disinfecting the working area surfaces and instruments with 85% ethanol solution and DNA-ExitusPlus IF | This experiment was done to show the effectiveness of applying both 85% ethanol solution and DNA-ExitusPlus IF to surfaces. Method: This is a screening test; therefore, all the surfaces were swabbed for touch DNA, then both 85% ethanol solution and DNA-ExitusPlus IF were applied. Finally, the surfaces were swabbed. A number of samples collected: a total of 24 replicate cotton swabs for pre- and post-cleaning of different surfaces of benches, cabinets, drawers, and tools. |
3 | Disinfecting the PCR cabinets using different exposure time of UV light | This experiment was done to show the effectiveness of using different exposure times of UV irradiation to samples. Method: Here, we have applied saliva (~ 20 ng/ul) in different surfaces and then we have swabbed each spot in different timings. Number of samples collected: a total of 12 replicate cotton swabs for each time exposure on the working area of PCR cabinets. |
4 | Disinfecting the working area using different exposure time of DNA-ExitusPlus IF | This experiment was done to show the effectiveness of using different exposure time of DNA-ExitusPlus IF to samples. Method: Here, we have applied saliva (~ 20 ng/ul) in different surfaces and then we have swabbed each spot in different timings. Number of samples collected: a total of 6 replicate cotton swabs for each time exposure in DNA collection benches. |
5 | Disinfecting the working area using different exposure time of bleach | This experiment was done to show the effectiveness of using different exposure times of bleach to samples. Method: Here, we have applied first saliva (~ 20 ng/ul) in different surfaces and then we have swabbed each spot in different timings. Number of samples collected: a total of 14 replicate cotton swabs for each time exposure in DNA collection benches. |
6 | Disinfecting the working area using different concentrations of ethanol solution | This experiment was done to show the effectiveness of using different concentrations of ethanol solution to samples. Method: Here, we have applied saliva (~ 20 ng/ul) in different surfaces and then we have swabbed each spot in different concentrations. Number of samples collected: a total of 10 replicate cotton swabs for each concentration in DNA collection benches. |
7 | DNA testing of gloves during work | This experiment was designed to check the possibility of DNA transfer using gloves during work. Method: This is a screening test, in which different used gloves were swabbed during their lab work. Number of samples collected: a total of 6 replicate cotton swabs for each glove |
8 | Talking in the presence of an open tube. | This experiment was done to detect any possibilities for DNA contamination in pre- and post-PCR working area. Method: tubes containing DNA extract was used to talk while the tubes were open, in pre- and post-PCR procedures without wearing masks. Number of samples collected: a total of 8 replicate tubes for each experiment. |
9 | Presence of DNA in the air | In this experiment, it was designed to check if the air contains any DNA. Method: swabs were taken from air by moving the air around different locations. Number of samples collected: a total of 10 replicate cotton swabs for each location. |