“…It becomes un-ionized hypochlorous acid (HOCl) by hydrolysis, which is an extremely potent bactericidal agent (Dukan, Belkin, & Touati, 1999;Huang, Hung, Hsu, Huang, & Hwang, 2008;Okamoto et al, 2006). Hypochlorous acid (HOCl) solution has a characteristic that major chlorine species is hypochlorite ion (OCl À ) when pH is high, while on the other hand, hypochlorous acid produces chlorine gas when pH is low (Boyette, Ritchie, Carballo, Blankenship, & Sanders, 1993). It has also been reported that concentration of un-ionized hypochlorous acid (HOCl) increases when pH range is from 4 to 7 (Nakagawara et al, 1998).…”