Body Fluids Conference Jointly hosted by the Forensic Science Society & the Centre for Forensic Investigation, University of Teesside: 18–19 April 2008 Convenors: Julie Allard and Brian Rankin
✍ Scribed by Joanne Hulme
- Publisher
- Elsevier Science
- Year
- 2010
- Tongue
- English
- Weight
- 213 KB
- Volume
- 50
- Category
- Article
- ISSN
- 1355-0306
No coin nor oath required. For personal study only.
✦ Synopsis
Whatman No.1 Qualitative Filter Paper, Whatman Grades 1 and 3 Filter Papers and Banner Blotting Paper. Items tested were seeded with previously frozen semen. The tests showed that there was not a great deal of difference in the papers at 2 min and between 5 and 10 min. What was established is that the longer the AP is left to react, the greater the dilution of semen that is detectable. After several hours, faint purple reactions and purple speck reactions were obtained. At 4 h it was possible to detect a 1-in-1000 dilution on Whatman Grade 3 Filter Paper. Some of the findings from these studies have meant that many BFF laboratories no longer have a two-minute cut-off point.
Another variable considered in the experimental studies was the amount of water used to dampen the items under test and which items should be dampened: to wet the paper, to wet the exhibit or to wet both? These tests involved trying out variations on 32 different types of fabric, including a cotton facecloth, poly/cotton t-shirt, polyester fleece, carpet, suede jacket, wool sweater, double layer cotton knickers, elastane top, polyester skirt, and a corduroy skirt. In general, the reactions seemed to be quicker when the 'exhibits' and blotting papers were wet but semen was still detected when the wet/ dry methods were tested. There were no definitive conclusions relating to whether fabric type is likely to affect the results. Some recommendations included considering the specific circumstances of the case in question, assessing expectations, gathering information, consideration of the fabric type, approach to search and recovery, time since deposition, time to deposition (for vaginal drainage stains) and potential for primary and/or secondary transfer.
In another series of tests, fresh semen at a series of dilutions was seeded on pairs of knickers which were then placed in bags and put in a cupboard for a week. These were then tested for AP using the blot method, a spray method and direct aerosol application of the reagent.