Laboratory safety knowledge
(1) When using flammable, explosive, corrosive and toxic chemicals and electrical equipment, etc., the operating regulations shall be strictly observed. Use electrical equipment with special care. Never use wet hands to turn on the switches and electrical switches. Do not use any leaking instrument to prevent electric shock. The appliance should be cut off after use.
(2) Eating, drinking and smoking are strictly prohibited in the laboratory, and all chemicals are prohibited from being imported. Wash your hands after the experiment.
(3) Do not splash on the skin and clothing when using strong corrosive agents such as chromic acid lotion, concentrated acid, and concentrated alkali. When you encounter concentrated acid, toxic or irritating gas, liquid, etc. in the experiment, you should operate in a fume hood. When using a test tube to heat a liquid, the test tube mouth should not be facing people. Do not look down on a heated container.
(4) Familiar with the storage place and use method of fire equipment. In case of an accident, corresponding measures should be taken immediately.
Washing of glass instruments
The cleaned glassware should be transparent, and its inner wall should be evenly wetted by water without hanging water drops.
General utensils such as beakers, reagent bottles, and Erlenmeyer flasks can be washed with tap water first, and then washed with ordinary washing liquid prepared by washing powder, decontamination powder, and so on. , Then rinse with tap water, and finally rinse the inner wall 2 to 3 times with a small amount of deionized water.
Burettes, volumetric flasks, pipettes, etc., due to their precise volume and special shape, should not be used to mechanically wipe their inner walls with a brush. Usually, the inner wall is soaked with a special washing solution, and then washed with tap water and deionized water in order.
Special detergents include hydrochloric acid solution and chromic acid washing solution. Chromic acid pickling liquid is highly corrosive, oxidative and acidic, so special care should be taken when using it. In addition, the hydrochloric acid-ethanol solution (1: 2) is often used to wash absorption cells, colorimetric tubes, and pipettes after being dyed with colored solutions or organic reagents.
干燥 Drying of glass instruments
The washed glass instrument can be dried upside down naturally. Or put it in an electric drying box and dry it at about 105 ℃.
For graduated volumetric instruments that cannot be dried by high temperature heating methods, such as pipettes, pipettes, volumetric flasks, burettes, etc., rinse with a small amount of organic solvent such as acetone or ethanol, then pour out the aqueous mixture and dry Dry or blow dry with hot air.