NCJ Number
215142
Journal
Journal of Forensic Sciences Volume: 51 Issue: 4 Dated: July 2006 Pages: 790-794
Date Published
July 2006
Length
5 pages
Annotation
This study developed an ultraviolet (UV) irradiation protocol for treating water, tubes, and polymerase chain reaction (PCR) plates used in the amplification of low-copy-number (LCN) DNA, so as to reduce the risk of contamination of the target DNA sample.
Abstract
Using the described UV irradiation protocols, this experiment documented a decrease in the incidence of "drop-ins" (contamination from lab equipment) found in the target DNA sample. These UV irradiation methods can be considered a safe means for decontaminating laboratory equipment without compromising the sensitivity of LCN PCR DNA amplification. Overall, there was a decrease in concentration of DNA recovered from labware as the duration of treatment increased. Various positions for specific types of labware in relation to the UV source reduced the amount of time required for optimum decontamination. Lining the area around the samples with aluminum foil further reduced the amount of time necessary for irradiation. Since the protocols used required less irradiation time than previous studies, PCR sensitivity for the target DNA sample was not affected, and the lifespan of the UV lamps was extended. Under the optimized conditions used, the UV sterilization parameters for pertinent labware in a Stratalinker 2400 lined with foil were as follows: 10 minutes for dry 0.2 ml tubes, 30 minutes for dry 1.5 ml tubes and PCR plates, 45 minutes for 1.5 and 15 ml tubes filled with water, and 75 minutes for 50 ml tubes with water. Tubes must be positioned prone on their sides, and PCR places should be within 1 inch of the UV light source. Contamination was defined as recovery of DNA greater than 0.04 pg/ml of DNA recovered from the sample. 6 figures and 10 references