1. Department of Chemistry Education, Faculty of Teacher and Training Education, Universitas Muhammadiyah Cirebon , Jl. Fatahillah, Watubelah, Sumber, Kabupaten Cirebon 45611 , Indonesia
2. Department of Chemistry, Graduate School of Science, Osaka University , 1-1 Machikaneyama, Toyonaka, Osaka 560-0043 , Japan