Woodford Holly, Mitchell Natasha, Henry Julianne
Faculty of Science and Technology, University of Canberra, Australian Capital Territory 2617, Australia.
Forensic Science SA, GPO Box 2790, Adelaide, South Australia 5001, Australia.
Sci Justice. 2021 Mar;61(2):170-174. doi: 10.1016/j.scijus.2020.11.001. Epub 2020 Nov 21.
The Phadebas® Forensic Press Test (PFPT) is an enzyme-based colorimetric test used to visualise and locate latent saliva stains on forensic exhibits. The test relies upon the presence of the enzyme α-amylase which is present in high levels in saliva. Even though the optimal in vitro temperature for α-amylase activity is 37 °C, the PFPT manufacturer's protocol specifies that the PFPT should be carried out at room temperature (RT). In this study, we compared the performance of the PFPT at RT and 37 °C using combinations of four fabric types (cotton, polyester, acrylic and a cotton/polyester blend), three saliva dilutions (neat, 1:10 and 1:100) and stains aged for four time periods (1 day, 1 week, 1 month and 3 months). The intensity of the PFPT colour reactions at RT and 37 °C were not statistically different across all fabric types, saliva concentrations and stain ages, indicating that maximum sensitivity and performance of the PFPT can be achieved at RT.
法德巴斯®法医按压试验（PFPT）是一种基于酶的比色试验，用于在法医物证上显现和定位潜在的唾液污渍。该试验依赖于唾液中高含量存在的α-淀粉酶。尽管α-淀粉酶活性的最佳体外温度为37°C，但PFPT制造商的方案规定PFPT应在室温（RT）下进行。在本研究中，我们使用四种织物类型（棉、聚酯、腈纶和棉/聚酯混纺）、三种唾液稀释度（原液、1:10和1:100）以及四个老化时间段（1天、1周、1个月和3个月）的污渍组合，比较了PFPT在室温及37°C下的性能。在所有织物类型、唾液浓度和污渍老化时间中，室温及37°C下PFPT颜色反应的强度无统计学差异，这表明在室温下可实现PFPT的最大灵敏度和性能。
