After reaction, the concentration of by-products such as LA, 5-
HMF and furfural was conducted using a HPLC system (Agilent,
USA, 1200 Series high-performance liquid chromatography)
equipped with Zorbax Eclipse Plus C18 column and a UV–Vis
Detector at 286 nm. The mobile phase consisted of 0.05 mol/L
phosphate buffer solution (pH 2.6)-methanol (85:15, V/V).