1. CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
2. University of Chinese Academy of Sciences, Beijing 100049, China
3. Institute for Clinical Chemistry and Pathobiochemistry, University Hospital Tuebingen, Hoppe-Seyler-Str. 3, Tuebingen 72076, Germany
4. German Center for Diabetes Research (DZD), Tuebingen 72076, Germany
5. Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Zentrum Muenchen at the University of Tuebingen, Tuebingen 72076, Germany
6. Internal Medicine 4, University Hospital Tuebingen, Otfried-Mueller-Str. 10, Tuebingen 72076, Germany