红外和紫外可见分光光谱法初步鉴别餐饮废油

Preliminary identification of waste cooking oil by the infrared spectrum and ultraviolet-visible spectrum

目的：建立简便、快速的餐饮废油、生物柴油以及合格食用油的鉴别检测方法。方法选择市售普通食用油、餐馆用油、生物柴油和餐饮废油(包括潲水油和煎炸老油)为研究对象，以1745 cm-1波数处的共有吸收峰为基准，比较各油脂红外光谱特征吸收峰相对强度；在230~800 nm 范围内，比较各油脂的紫外可见吸收曲线，对油脂品质进行比较鉴别。结果比较红外图谱发现，各油脂在3473、3008、1652 cm-1附近对1745 cm-1的吸收峰相对强度差别较大，可以此作为判别依据；通过观察比较各油脂在紫外可见光谱图中的起始和终止吸收波长，以及在668 nm处是否有较高的吸光度或特征吸收峰，可对油脂品质进行鉴别。结论综合红外和紫外可见两种光谱方法的检测结果，本方法可初步地快速鉴别合格食用油与餐饮废油。

Objective To establish a simple, fast distinguish method for waste cooking oil, biodiesel and qualified cooking oils. Methods Several common cooking oils bought from supermarket, roadside restaurant oil, biodiesel and waste cooking oil (including hogwash oil and frying oil) were compared based on the relative intensity ratio of infrared (IR) spectra with a characteristic absorption peaks 1745 cm-1. Ultraviolet-visible (UV-vis) spectra (230～800 nm) were successively used to distinguish the difference. Results The relative inten-sity ratio of IR spectra (absorption peaks 1745 cm-1) could be obviously distinguished, especially at 3473 cm-1/1745 cm-1, 3008 cm-1/1745 cm-1 and 1652 cm-1/1745 cm-1, and thus can be used as basis for discrimination. By comparing the starting and end wavelength of UV-vis spectra of the test oils, and whether the spectrum has higher absorbance or obvious absorption peak at 668 nm, the quality of test oil could be recognized. Conclusion The preliminary identification method can be used to quickly identify the qualified oils from waste oils.