1. Biliary Surgical Department West China Hospital, Sichuan University Chengdu, Sichuan 610225, P. R. China
2. Analytical & Testing Centre, Sichuan University, Chengdu, Sichuan 610041, P. R. China
3. Key Laboratory of Green Chemistry & Technology of Ministry of Education, Sichuan University, Chengdu, Sichuan 610064, P. R. China