Abstract：
BACKGROUND: Blood and semen stains are the most common biological stains encountered at crime scenes. The washing of biological stains is a common application that perpetrators use to spoil the crime scene. With a structured experiment approach, this study aims to investigate the effects of washing with various chemicals on the ATR-FTIR detection of blood and semen stains on cotton.
METHODS: On cotton pieces, a total of 78 blood and 78 semen stains were applied, and each group of six stains was immersed or mechanically cleaned in water, 40% methanol, 5% sodium hypochlorite solution, 5% hypochlorous acid solution, 5 g/L soap dissolved pure water, and 5 g/L dishwashing detergent dissolved water. ATR-FTIR spectra gathered from all stains and analyzed with chemometric tools.
CONCLUSIONS: According to performance parameters of developed models, PLS-DA is a powerful tool for discrimination of washing chemical for both washed blood and semen stains. Results from this study show that FTIR is promising for use in detecting blood and semen stains that have become invisible to the naked eye due to washing of the findings.
CONCLUSIONS: Our approach allows blood and semen to be detected on cotton pieces using FTIR combined with chemometrics, even though it is not visible to the naked eye. Washing chemicals also can be distinguished via FTIR spectra of stains.
METHODS: On cotton pieces, a total of 78 blood and 78 semen stains were applied, and each group of six stains was immersed or mechanically cleaned in water, 40% methanol, 5% sodium hypochlorite solution, 5% hypochlorous acid solution, 5 g/L soap dissolved pure water, and 5 g/L dishwashing detergent dissolved water. ATR-FTIR spectra gathered from all stains and analyzed with chemometric tools.
CONCLUSIONS: According to performance parameters of developed models, PLS-DA is a powerful tool for discrimination of washing chemical for both washed blood and semen stains. Results from this study show that FTIR is promising for use in detecting blood and semen stains that have become invisible to the naked eye due to washing of the findings.
CONCLUSIONS: Our approach allows blood and semen to be detected on cotton pieces using FTIR combined with chemometrics, even though it is not visible to the naked eye. Washing chemicals also can be distinguished via FTIR spectra of stains.
摘要：
背景：血液和精液污渍是犯罪现场最常见的生物污渍。清洗生物污渍是犯罪者用来破坏犯罪现场的常见应用。通过结构化实验方法，本研究旨在研究用各种化学物质洗涤对ATR-FTIR检测棉花血液和精液污渍的影响。
方法：在棉片上，总共应用了78种血液和78种精液污渍，每组六种污渍浸入水中或机械清洗，40%甲醇,5%次氯酸钠溶液，5%次氯酸溶液，5g/L肥皂溶解纯水，和5g/L洗碗洗涤剂溶解水。从所有染色剂收集ATR-FTIR光谱并用化学计量学工具分析。
结论：根据开发模型的性能参数，PLS-DA是用于区分洗涤过的血液和精液污渍的洗涤化学品的强大工具。这项研究的结果表明，FTIR有望用于检测由于清洗发现而肉眼看不到的血液和精液污渍。
结论：我们的方法允许使用FTIR结合化学计量学在棉片上检测血液和精液，即使肉眼看不见。洗涤化学品也可以通过污渍的FTIR光谱来区分。
方法：在棉片上，
结论：根据开发模型的性能参数，
结论：我们的方法允许使用FTIR结合化学计量学在棉片上检测血液和精液，
