ATR-FTIR spectroscopy and GC-MS data of blow fly puparia

This study uses empty puparia of four forensically relevant blow fly species. Species identification of these insect traces at scenes of discoveries of human remains, is neccessary to help with the estimation of the minimal time since death. Since morphological species identification of (fragmented) puparia is difficult, new methods for species identification, like ATR-FTIR spectroscopy and GC-MS are tested. Empty puparia of Lucilia sericata, Calliphora vicina, Protophormia terraenovae and Chrysomya albiceps were stored in garden soil at 25 °C for either one day or one month. Puparia were cleaned, cut into fragments and measured on an ATR-FTIR spectrometer (JASCO FT/IR-4200 with PIKE Technologies GladiATR accessory) or were subjected idividually to n-hexane and the extract was measured on a 7890A, Agilent Technologies gas chromatograph. While ATR-FTIR spectral data was normalized via the standard normal variate, the chromatograms resulting from GC-MS were analyszed using MSD ChemStation and the integration and peak alignment was done manually. Non-hydrocarbons, hydrocarbons with an overall maximum abundance below 0.5% and hydrocarbons that occurred in less than 20% of the samples of either species or treatment were removed from the dataset. tecRep = technical replicate (i.e. single puparia), bioRep = biological replicate (i.e. separate oviposition events of the blow flies), Age = storage/weathering time of the puparia -> 1D = 1 day 1M = 1 Month, CA = Chrysomya albiceps, CV = Calliphora vicina, LS = Lucilia sericata, PT = Protophormia regina, RI = retention index. In the column “hydrocarbon”, “unknown CHC” = substances identified as hydrocarbons. “unknown” = substances where we could not unambigously decide whether or not it was a hydrocarbon, and/or where the peak represented a blend of a hydrocarbon and a non-hydrocarbon compound, “unknown, unsaturated” = unknown hydrocarbon, but the mass spectrum indicates at least one unsaturation, (cf) = identification tentative.本研究采用了四种与法医学相关的丽蝇物种的空蛹壳。在人类遗体发现现场对这类昆虫痕迹开展物种鉴定，是推断死亡后最小间隔时间的必要环节。由于（破碎状态的）蛹壳的形态学物种鉴定难度较高，研究人员对衰减全反射傅里叶变换红外光谱（ATR-FTIR）、气相色谱-质谱联用（GC-MS）等新型物种鉴定方法进行了测试。 将丝光绿蝇（Lucilia sericata）、红头丽蝇（Calliphora vicina）、原丽蝇（Protophormia terraenovae）以及白额丽蝇（Chrysomya albiceps）的空蛹壳，置于25℃的菜园土壤中分别存放1天或1个月。随后对所有蛹壳进行清洗、切割为碎片，其中一部分使用搭载PIKE Technologies GladiATR附件的JASCO FT/IR-4200型衰减全反射傅里叶变换红外光谱仪完成检测；另一部分则分别以正己烷进行萃取，将萃取液置于安捷伦7890A型气相色谱仪（Agilent Technologies）上进行检测。 衰减全反射傅里叶变换红外光谱（ATR-FTIR）光谱数据通过标准正态变量法完成归一化处理；气相色谱-质谱联用（GC-MS）所得色谱图通过MSD ChemStation软件进行分析，峰积分与峰对齐操作均采用手动方式完成。本数据集剔除了三类物质：非烃类化合物、总最大丰度低于0.5%的烃类化合物，以及在任一物种或处理组的样本中出现比例低于20%的烃类化合物。 本研究相关缩写定义如下：tecRep（技术重复）= 单只蛹壳的单次检测，bioRep（生物学重复）= 丽蝇的不同产卵批次，Age（存放/老化时长）= 蛹壳的存放时长：1D = 1天，1M = 1个月；CA = 白额丽蝇（Chrysomya albiceps），CV = 红头丽蝇（Calliphora vicina），LS = 丝光绿蝇（Lucilia sericata），PT = 原丽蝇（Protophormia regina），RI = 保留指数。 在"hydrocarbon（烃类物质）"列中，"unknown CHC"指被鉴定为烃类的未知物质；"unknown"指无法明确判定是否为烃类，或该峰同时包含烃类与非烃类化合物的混合物；"unknown, unsaturated"指未知烃类，但质谱图显示至少存在一个不饱和键；(cf) = 暂定鉴定。