Comparison between various DNA sterilization procedures applied in forensic analysis

Al-Snan, Noora R.; Alraimi, Najib M.

doi:10.1186/s41935-022-00265-7

Egyptian Journal of Forensic Sciences

Table 2 The detection of gDNA from different experiments obtained through HID Real-Time PCR Analysis Software v1.2

From: Comparison between various DNA sterilization procedures applied in forensic analysis

Sr. No	Experiment details	Amount of gDNA (ng/ul) (mean)		**Ct values (mean)
1) Disinfecting the working area surfaces and instruments with 85% ethanol solution
1	Thermomixers (1), DNA CW lab	Precleaning: 0.002	Post-cleaning: 0.0004	31.5, 33.8
2	Thermomixers (2), DNA CW lab	Precleaning: 0.0021	Post-cleaning: 0.0022	31.4, 31.3
3	Thermomixers (3), DNA DB lab	Precleaning: 0.0015	Post-cleaning: 0.0023	31.9, 31.2
2) Disinfecting the working area surfaces and instruments with 85% ethanol solution and DNA-ExitusPlus IF
4	Bench inside the DNA extraction room, DNA CW lab	Precleaning: 0.0052, post-cleaning ethanol: 0.0035, Post-cleaning DNA-exitus: 0.0005		33.39, 30.2, 30.76
5	PCR cabinet, DNA CW lab	Precleaning: 0.0041, post-cleaning ethanol: 0.0003, post-cleaning DNA-exitus: 0.0003		30.54, 34.28, 34.34
6	PCR cabinet, DNA DB lab	Precleaning: 0.0011	Post-cleaning DNA-exitus: *UD	32.34, UD
7	PPE drawer, DNA DB lab	Precleaning: 0.0013	Post-cleaning ethanol: 0.0006	33.11, 32.14
8	1000ul pipettes, DNA CW lab	Precleaning: 0.061	Post-cleaning ethanol: 0.0004	3.74, 26
3) Disinfecting the PCR cabinets using different exposure times of UV light
9	Induced contamination, UV light, 0 min, control	0.0081		33.54
10	Exposure UV light, 5 min	0.0045		34.36
11	Exposure UV light, 10 min	0.0063		33.89
12	Exposure UV light, 15 min	0.0009		36.65
13	Exposure UV light, 20 min	0.0024		35.32
14	Exposure UV light, 25 min	0.0018		35.61
4) Disinfecting the working area using different exposure times of DNA-ExitusPlus IF
15	Induced contamination, DNA-Exitus, 0 min, control	0.0507		35.41
16	Post-cleaning, DNA-Exitus, 10 min	0.0011		34.41
17	Post-cleaning, DNA-Exitus, 15 min	UD		36.35
5) Disinfecting the working area using different exposure times of bleach
18	Induced contamination, bleach, 0 min, control	0.0845		33.12
19	Post-cleaning, bleach, 10 min	UD		UD
20	Post-cleaning, bleach, 15 min	0.0002		34.41
21	Post-cleaning, bleach, 20 min	UD		UD
22	Post-cleaning, bleach, 25 min	UD		UD
23	Post-cleaning, bleach, 30 min	UD		UD
24	Post-cleaning, bleach, 35 min	0.0003		36.35
6) Disinfecting the working area using different concentrations of ethanol solution
25	Induced contamination, ethanol, 0%, control	0.0096		27.05
26	Post-cleaning, ethanol, 70%	0.0045		30.4
27	Post-cleaning, ethanol, 75%	0.0038		30.63
28	Post-cleaning, ethanol, 80%	0.0043		30.46
29	Post-cleaning, ethanol, 85%	0.0017		30.17
7) DNA testing of gloves during work
30	Random swabbing glove 1	0.0022		31.36
31	Random swabbing glove 2	0.0033		30.82
32	Random swabbing glove 3	0.0022		31.38
8) Talking in the presence of an open tube
33	Talking inside DNA tube, pre-PCR 1	UD		UD
34	Talking inside DNA tube, pre-PCR 2	0.0002		34.91
35	Talking inside DNA tube, post-PCR 1	0.0006		33.27
36	Talking inside DNA tube, post-PCR 2	0.0002		34.51
9) Presence of DNA in the air
37	Air swabbing, staff office, CW lab	0.0045	30.38
38	Air swabbing, DNA extraction room, CW lab	0.0003	34.34
39	Air swabbing, staff office, DB lab	0.0012	32.21
40	Air swabbing, PCR cabinet, CW lab	UD	UD
41	Air swabbing, PCR cabinet, DB lab	UD	UD

*UD Underdetermined, **Ct values Cycle Threshold.
R² values: 0.998 and 1.0

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