Normal phase silica gel 60 f254 hptlc glass plates

HPLC grade acetonitrile from Merck (Darmstadt, Germany), HPLC grade phosphorous acid from Sigma-Aldrich (Steinheim, Germany), and Wahaha pure water were purchased. Reference compounds for 3,4-CQA (batch number: P0343, purity: >98%) were obtained from Shanghai Youche biotechnology Co., LTD. 3,5-CQA (batch number: 111782–201706, purity: >98%) and 4,5-CQA (batch number: 111894-201102, purity: >98%) were obtained from the Chinese Food and Drug Accreditation Institute. 1,1-Diphenyl-2-picrylhydrazyl (DPPH˙) free radical was obtained from Munich, Germany, and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS∗+) free radical was obtained from Sigma. All other chemicals and solvents used were of analytical grade. Normal-phase silica gel 60 F254 HPTLC glass plates (Merck, Darmstadt, Germany) of a size of 20 × 10 cm were used to perform separation, and Automatic TLC Sampler 4 (ATS4; CAMAG, Muttenz, Switzerland) was used for sampling.

HPLC grade methanol from Merck (Darmstadt, Germany), MS grade formic acid from Sigma-Aldrich (Steinheim, Germany), and HPLC grade acetonitrile from Merck (Darmstadt, Germany) were purchased. A Milli-Q system provided ultrapure water (Millipore, Bedford, MA, USA). Reference compounds for icariin (batch number: 110737-201516, purity: >98%), gallic acid (batch number: 110831-201605), and daidzein (batch number: 11502-20-0402) were obtained from the Chinese Food and Drug Accreditation Institute. 1,1-Diphenyl-2-picrylhydrazyl (DPPH^•) free radical was obtained from Munich, Germany, and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) ABTS^∗+ free radical was from Sigma. All other chemicals and solvents used were of analytical grade. Normal phase silica gel 60 F₂₅₄ HPTLC glass plates with a size of 20 × 10 cm were used to perform separation (Merck, Darmstadt, Germany).