2.7 Analysis of Products
GC-MS was performed with an Agilent 5975C-7890A equipped with a capillary column (HP-5MS 30 m×mm×0.25 μm) and EI ion source (70 eV).The following operating condition was used: a column temperature program of 50 ºC (3 min), 7 ºC/min to 150 ºC, 150 ºC for 10 min, 20 ºC /min to 300 ºC, 300 ºC for 20 min. GPC analysis was performed with a Waters 1515/2414 liquid chromatography system (Waters 1515/2414, Waters Co., USA). The tetrahydrofuran (THF) was used as the eluent. The lignin and depolymerized products were dissolved in THF at a concentration of 5 mg mL-1.The 2D HSQC was performed on a Bruker AV 600 MHz spectrometer. And 100 mg of lignin and lignin oil were dissolved in 0.5 mL DMSO-d6.