DISTILLED WATER (Aqua destillata) — the water purified of the impurity dissolved in it by distillation.
Of century is widely applied as solvent, including and in the medical purposes, to preparation of solutions of medicinal substances. Of century, used for preparation of drugs (e.g., eye drops), will sterilize previously. Of century receive from drinking water (see. Water ) in special distillation apparatuses — akvadistillyator (see. Distillation, akvadistillyator ). Water by distillation is exempted from nonvolatile impurity for what it is previously boiled within 15 — 30 min. in an open heater or processed special chemical substances, transferring volatile substances to nonvolatile. The first portions of distillate discard. Of century, collected in the receiver, it has to be protected from hit of dust and other impurity. Received with observance of all necessary rules D. of century represents an inodorous transparent colorless liquid and taste, pH 5,0 — 6,8, with specific conductivity no more than 5x10 - 6 the solid residue shall not exceed 0,001%. Of century shall meet certain requirements for the content of deoxidizing substances, ammonia and ammonium salts, carbon dioxide, nitrates and nitrites, chlorides, sulfates, calcium and heavy metals.
When century of higher degree of purity needs D., it is subjected to repeated distillation and receive a redistillate (Aqua bidestillata, a synonym of redestillata). G the purpose of release of D. of century from organic matters before secondary distillation add to it a little (about 0,1 g/l) potassium permanganate and several drops konts. a chamois to - you. Water, free of traces of organic matters, is called depyrogenized (see. Water depyrogenized ). The bidistilled water is received and stored in quartz, tin, silver, platinum vessels.
For water treatment widely use ion-exchange resins (see. Ionites ). Water is consistently passed through a number of the columns filled with cation exchangers and anion exchangers. The water (so-called desalinized water) received thus on extent of cleaning and properties practically does not differ from D.
EL of century for drink is unsuitable since it does not contain microelements.
Bibliography: Voskresensky P. I. Technology of laboratory works, M., 1973; I. A. Tekhnologiya's Ants of drugs, M., 1971.
V. A. Popkov.