A cap, especially a disinfectant cap, is for protecting andor closing off the abdominal connector used in peritoneal dialysis, and to a detection device for peritoneal dialysis. An ozone solution is prepared by injecting the ozone gas into an acidic solution of pH 6 or below. An electrochemical reaction apparatus containing an electrolyte, wherein said electrochemical reaction apparatus is characterized in that the aforementioned solid polymer electrolyte composite is used as this electrolyte is also provided. 5% butterfat content, non-dairy coffee whitener, and mixtures thereof; and the beverage sweetener may be sucrose, glucose, fructose, artificial sweetener, and mixtures thereof.