建立了可用于13种易制毒化学品快速定性鉴定分析的衰减全反射傅立叶变换红外光谱（ATR-FTIR）方法。 长期以来, 由于缺乏定性判别依据, 红外光谱法仅被用于快速定性筛查分析。 为扩大红外光谱法在法庭科学领域的应用, 本研究收集并分析了152份各类缴获麻黄碱样品, 对匹配度系数法和特征吸收峰法这两种定性判别依据进行了考察和比较。 麻黄碱样品与标准品的匹配度系数区间为0.437～0.981, 整体趋势为纯度越高匹配度系数越高, 但匹配度系数与纯度并不成线性关系, 所以匹配度系数的阈值很难确定。 特征吸收峰的挑选原则为在2 500~650 cm-1范围内挑选8个相对吸收强度较高且不受常见掺杂物干扰的吸收峰。 当以全部特征吸收峰均检出为阳性检出依据时, 152份麻黄碱样品的阳性检出率为98.7%。 综合评价结果表明采用特征吸收峰法作为判别依据, 专属性强、 适用范围宽、 定性结果准确可靠。 确定了1-苯基-2-丙酮、 3,4-亚甲基二氧苯基-2-丙酮、 胡椒醛、 N-乙酰邻氨基苯酸、 邻氨基苯甲酸、 麻黄碱、 伪麻黄碱、 3-氧-2-苯基丁腈、 1-苯基-2-溴-1-丙酮、 N-苯乙基-4-哌啶酮、 4-苯胺基-N-苯乙基哌啶、 1-苯基-1-丙酮、 N-甲基-1-苯基-1-氯-2-丙胺这13种易制毒化学品的特征吸收峰。 采用基于特征吸收峰的ATR-FTIR法对易制毒化学品进行快速定性鉴定分析, 将极大提高易制毒化学品定性检验的鉴定效率、 降低检验鉴定成本。

For the first time, this study established an attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) method for fast qualitative analysis of 13 precursor chemicals. Due to the lack of qualitative identificationcriterion, FTIR has long just been used as a fast qualitative screening method. In order to expand its application in forensic sciences, two qualitative identification criteria of similarity coefficient method and characteristic peak method were investigated and compared based on the FTIR data of 152 seized ephedrine type samples. The range of the similarity coefficient values for ephedrine samples was 0.437～0.981. Generally speaking, sample with higher purity resulted in higher similarity coefficient value, but there is no linear relationship between the similarity coefficient value and the sample purity. Therefore, it is hard to select a threshold value. For characteristic peak method, eight peaks in the range of 2 500~650 cm-1 with relative high intensity and interference-free from common cutting agents were selected as the characteristic peaks. When the detection of all characteristic peaks was selected as the positive identification criteria, the positive detection rate for 152 ephedrine samples was 98.7%. Therefore, the characteristic peak method showed stronger specificity and wider application scope, and the results were reliable and accurate. This study established the characteristic peaks of 1-phenylpropan-2-one, 3,4-methylenedioxyphenylpropan-2-one, piperonal, N-acetylanthranilic acid, anthranilic acid, ephedrine, pseudoephedrine, 3-oxo-2-phenylbutanenitrile, 2-bromo-1-phenylpropan-1-one, N-phenethyl-4-piperidone, 4-anilino-N-phenethylpiperidine, 1-phenylpropan-1-one, and 1-chloro-N-methyl-1-phenylpropan-2-amine. The developed FTIR method that based on characteristic peak for precursor chemical identification provided a useful alternative to mass spectrometric method. It could significantly reduce the analysis time and cost, and greatly improve the identification efficiency.