Table 2.

Operating conditions of HPLC for carbonyl compounds analysis.

Operating Parameter	Specifications and Conditions
HPLC System	Shimadzu SCL-6B with Shimzdzu SPD-6AV UV/VIS detector at 360 nm
Analytical column	Shim-Pack CLC-ODS (M) 4.6 mm × 150 mm with a C18 guard column
Mobile phase	A: acetonitrile 100 (V), B: water/acetonitrile/tetrahydrofuran 50/45/5 (v/v)
Gradient elution	100% B for 5 min, and then 60:40% A:B for 15 min, finally 100% A for 5 min
Flow rate and injection volume	1.0 mL/min and 20 μL injection