Guide: The instruments that are often used in experiments should be washed and dried for use after each experiment. Different experiments have different requirements for drying. Generally, beakers, conical flasks and other instruments used for quantitative analysis can be used after washing.

   Instruments that should be frequently used in experiments should be washed and dried for use after each experiment. Different experiments have different requirements for drying. Generally, beakers, conical flasks and other instruments for quantitative analysis can be used after washing; while many instruments used for food analysis are required to be dry, some require no water marks, and some The requirement is anhydrous. The instrument should be dried according to different requirements. There are five main drying methods for the instrument:

1. Drying

   The cleaned instrument is controlled to remove moisture and dried in an oven at a temperature of 105~110°C for about 1 hour. It can also be dried in an infrared lamp drying oven. This method is applicable to general instruments. After drying, the weighing bottle should be cooled and stored in a desiccator. When drying thick-walled instruments with solid glass plugs, pay attention to heating up slowly and the temperature should not be too high to avoid rupture. The measuring device cannot be placed in an oven.

   The cleaned instrument can be dried in an electric drying oven (oven), but the water should be poured out as much as possible before putting it in. When placing the instrument, care should be taken to make the mouth of the instrument face down (the instrument that is unstable after inversion should be placed flat). An enamel plate can be placed on the bottom layer of the electric heating drying box to receive the water droplets from the instrument; so as not to make the water drop on the electric furnace wire, so as to avoid damage to the electric furnace wire.

2. Bake dry

   The beaker or evaporating dish can be dried on a small fire on the asbestos mesh. The test tube can be directly dried on a small fire. When operating, the test tube should be slightly inclined; the nozzle should be downward, and the test tube should be moved back and forth from time to time to drive out the water droplets.

3. To dry

   The cleaned instrument can be placed upside down on the instrument rack in a clean laboratory cabinet (the instrument that is unstable after inversion, such as a graduated cylinder should be placed flat) and let it dry naturally.

4. Blow dry

   Dry the instrument with compressed air or a hair dryer.

5. Dry with organic solvent

   Some measuring instruments with scales cannot be dried by heating; otherwise, the precision of the instrument will be affected. We can add some volatile organic solvents (such as alcohol or a mixture of alcohol and acetone) to the cleaned instrument (a small amount), tilt the instrument, turn the instrument and mix the water on the wall with the organic solvent . Then pour out, and a small amount of the mixture remaining in the instrument quickly evaporates to dry the instrument.