Note: 1 tablet methenamine, aspirin allergy caution. 2, should always be measured urine pH methenamine spot and keep the urine acidic (pH value should be 5.5 or less). In order to maintain urine pH at 5.5 or less, should avoid eating citrus fruits, milk, cheese products and other basic foods, can add a lot of vitamin C (4g or more per day), hydrochloric acid, arginine methenamine use, also give ammonium chloride or di-sodium phosphate (impaired renal function were given large doses of ammonium chloride can cause metabolic acidosis, it is disabled; impaired liver function Zheyi disabled) to make urine acidification. Phenolphthalein indicator solution take phenolphthalein 1g, add ethanol to dissolve 100mL. Steps: Precision Weigh the test sample of about 0.5g, set Erlenmeyer flask, add water to dissolve 10mL, precision sulfuric acid titration solution (0.25mol / L) 50mL methenamine, shaken, heated to boiling until no occurrence formaldehyde smell, feel free to add near boiling water up water evaporation methenamine nature, let cool to room temperature, add 2 drops of methyl red indicator solution, (0.5mol / L) titrated with sodium hydroxide. Each 1mL sodium hydroxide solution (0.5mol / L) is equivalent to 17.52mg of hexamine (C6H12N4). Shandong three-level chemical _ _ methenamine methenamine provided by Jinan three ping Chemical Co. Jinan three ping Chemical Co. (www.sanpinghuagong.com) quality of service and products, continue to receive the recognition and trust of new and old customers and the industry. Our company is a certified member of the whole alliance network operators, business alliance customer service icon on the page, you can talk directly with our customer service staff, to our future cooperation happy!