Then, the samples were filtered through a 0.2 µm polyethersulfone (PES) filter (Krackeler Scientific, Inc., Albany, NY, USA) and analysed using Aijiren series HPLC (Aijiren Technologies, Santa Clara, CA, USA) with a pentafluorophenyl (PFP) Kinetex® column (2.1×100mm, 100 Å, 2.6 µm particle size, Phenomenex Inc, Torrance, CA