According to a query to Baidu's encyclopedia, cinnamic acid, also known as β-phenylacrylic acid and 3-phenyl-2-propenoic acid, is an organic substance with the chemical formula C9H8O2, and is an organic acid isolated from the bark of cinnamon or benzoin. Phenylacrylic acid produced in plants by the deamination of phenylalanine degradation.

Take the appropriate amount of cinnamic acid, precision weighing, add methanol to make a solution containing 4mg per 1ml, as a test solution. According to the thin layer chromatography (Chinese Pharmacopoeia 2000 version of a Appendix VIB) test, respectively, absorb the test solution of 5μl, 15μl and 25μl, respectively, were spotted on the same sodium carboxymethylcellulose as a binder silica gel GF254 thin-layer plate, with petroleum ether (30-60 ℃) - ethyl formate - formic acid (15:5:1) the upper layer of the solution as an unfolding agent, unfolding, take out, air drying, and placed in a The chromatogram of the test article was examined under ultraviolet light (254 nm). In the chromatogram of the test material, no impurity spots were seen when the sample amount of cinnamic acid was 20 μg, 60 μg and 100 μg, respectively.