薄层色谱法(TLC)是一种简便、高效的分离方法。但用于鉴定却存在一定困难。这是因为,一方面作为定性指标的R_f值受多种因素的影响,难以重复,并且缺乏标准样品;另一方面对完全未知的样品,即使其R_f值和标准样品相同,也难以下结论。因此往往需要将TLC与其它鉴定手段,如红外光谱法(IR)和质谱法 Thin-layer chromatography (TLC) is a simple and efficient method of separation. However, there are some difficulties for identification. This is because, on the one hand, the value of R_f as a qualitative indicator is affected by many factors, is difficult to duplicate, and there is a lack of standard samples; on the other hand, it is difficult to draw conclusions about completely unknown samples even though their R_f values ​​are the same as standard samples. Therefore, it is often necessary to compare TLC with other means of identification, such as infrared spectroscopy (IR) and mass spectrometry