1. Department of Analytical and Environmental Science National Tsing Hua University 101, Section 2 Guang-Fu Road, East District Hsinchu 300044 Taiwan) R.O.C.
2. Nanomaterials Research Group School of Chemical Sciences, Universiti Sains Malaysia 11800 USM Penang Malaysia
3. School of Chemical Sciences Universiti Sains Malaysia Pulau Pinang Penang 11800 USM Malaysia