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How to clean laboratory glass instruments, see here

Apr 11, 2019

We all know that no matter what is used for a long time, it will become dirty. Especially the various glass instruments used in our laboratory are usually used to hold various chemicals. If not cleaned, some chemicals will remain in the container. Therefore, the data obtained by interference in the chemical reaction will also be inaccurate. The traditional method of washing the instrument is to rinse with water and brush, but this method is cumbersome and easy to wash, reducing the life of the instrument. Here are a few tips for cleaning glassware.

lab furniture-04.11

1. Preparation method of chromic acid washing liquid: 20 g fine industrial grade K2Cr2O7, add water 40ml, heat to dissolve, after cooling, 360ml concentrated sulfuric acid is slowly added to the above solution, after cooling, transfer to a bottle with a glass stopper . (requires a large amount can be prepared in proportion)

Uses: Wash general oil stains with a small amount of lotion or soak overnight.

Precautions: It is highly corrosive and prevents burns on skin and clothing. It can be used repeatedly after recycling, and the storage bottle should be tight to prevent water absorption failure; if it is green, it will be invalid and will be discharged after treatment.

2. Industrial hydrochloric acid preparation method: V (hydrochloric acid): V (water) = 1..1. Uses: Used to clean alkaline dirt and most inorganic substances. Note: The used lotion can be recycled. Alkaline lotion preparation method: 10% aqueous sodium hydroxide solution. Uses: Wash oil and some organic matter.

Note: The wash bottle is filled with plastic or rubber stopper. Alkaline ethanol washing solution Preparation method: 60 g NaOH dissolved in 80 ml of water, add 95% ethanol to 500 ml (large amount can be expanded in proportion).

Uses: Wash grease, tar, resin, etc. Note: The liquid storage bottle is filled with rubber stopper; it is easy to be used for a long time; it is anti-volatile and fireproof.

3. Preparation method of alkaline potassium permanganate washing solution: 4 g of potassium permanganate is dissolved in a small amount of water, 10 g of sodium hydroxide is added, and water is added to 100 ml (the amount can be expanded according to the ratio). \

Uses: Wash oil, organic matter. Soak.

Note: Brown MnO2 is precipitated in the crude oil stain after washing, and it can be removed by hydrochloric acid or oxalic acid.

4, sodium phosphate washing solution Preparation method: 57 g sodium phosphate, 28.5 g sodium oleate, dissolved in 470ml water (large amount can be expanded according to the proportion).

Uses: Wash carbon residue. Soak and wash.

Note: Soak for a few minutes, then rinse.

5, iodine-potassium iodide washing solution preparation method: 1 g iodine, 2 g potassium iodide mixed grinding, dissolved in a small amount of water, then add water to 10ml (large amount can be expanded according to the ratio).

Uses: Wash brown residue of silver nitrate.

Note: Soak for a few minutes, then rinse.

6, commonly used organic solvent preparation methods: such as benzene, ether, acetone, ethanol, dichloroethane, chloroform. (A large amount can be expanded proportionally).

Uses: There are a small amount of organic matter that is difficult to wash by general methods.

Note: Pay attention to toxicity and flammability; used waste solvent should be used after recycling and distillation.