基于紫外可见积分球反射光谱法鉴定血痕经历时间

目的建立一种快速鉴定血痕陈旧度的方法。方法在实验室条件(20℃、25℃、30℃)下,使用UV-2450型紫外可见分光光度计,利用反射附件ISR-240A积分球,以BaSO_4标准白板做参比,间隔一定时间测定健康人耳静脉血血痕纱布的反射光谱,采集特定波长反射率R_(541)、R_(577),计算R_(541)/R_(577)值,使用SPSS 17.0软件进行直线拟合与回归分析。结果一定条件下8 h内,血痕经历时间与其特定波长紫外可见反射率比值回归分析的R~2均大于0.8,回归方程成立,血痕经历时间与R_(541)/R_(577)值具有高度相关性。结论所建立的方法简便、快速、无损,可靠性好,可以对实验室条件下8 h内血痕经历时间进行鉴别。

Determination of Bloodstain Age by UV Visible Integrating Sphere Reflection Spectrum

ObjectiveTo establish a method for rapid identification of bloodstain age.MethodsUnder laboratory conditions(20 ℃, 25 ℃and 30 ℃), an integrating sphere ISR-240A was used as a reflection accessory on an UV-2450 UV-vis spectrophotometer, and a standard white board of BaSO4 was used as reference, the reflection spectrums of bloodstain from human ears’venous blood were measured at regu-lar intervals. The reflection radiosR541 andR577 at a specific wavelength were collected and the value of R541/R577 was calculated. The linear fitting and regression analysis were done by SPSS 17.0.ResultsThe results of regression analysis showed thatR2 of the ratios of bloodstain age to UV visible reflectivity in specific wavelengths were larger than 0.8 within 8 hours and under certain circumstances. The regression equation was established. The bloodstain age had significant correlation with the value ofR541/R577.Con-clusionThe method of inspection is simple, rapid and nondestructive with a good reliability, and can be used to identify the bloodstain age within 8 hours elapsed-time standards under laboratory conditions.