December 9, 2021 Longchang Chemical

How to store laboratory chemical reagents?

Chemical reagents must be stored properly, because the quality of the reagents directly affects the accuracy of the experimental results. Chemical reagents often deteriorate due to improper storage during storage. Some reagents are easy to absorb moisture and deliquesce or hydrolyze; some easily react with oxygen, carbon dioxide or other gases diffused in the air, and some reagents will deteriorate due to the influence of light and ambient temperature. Therefore, corresponding measures must be taken to properly store the reagents according to the different properties of the reagents.

Chemical reagents are inevitably interfered by external conditions during the storage process. You need to be able to achieve eight protections in the laboratory: anti-volatile, anti-moisture, anti-deterioration, anti-light, anti-poisoning, anti-shock, anti-fire, and anti-rat.

  1. Anti-Volatilization
  2. Oil seal: ammonia, concentrated hydrochloric acid, concentrated nitric acid and other volatile inorganic liquids, drop 10-20 drops of mineral oil on the liquid surface to prevent volatilization (vegetable oil is not available).
  3. Water seal: add 5mL water to carbon disulfide, it can be stored for a long time. Water is added to the mercury to prevent mercury vapor from entering the air. Some sulfur powder was placed beside the mercury, but once it was lost, the sulfur powder was scattered to eliminate the mercury in the chemical reaction.
  4. Wax seal: ether, ethanol, formic acid and other volatile liquids that are lighter than water or easily soluble, as well as volatile solids such as naphthalene and iodine, tightly stop the bottle, and coat the mouth with wax. In addition to wax sealing of the original bottle of bromine, the original bottle should be placed in a plastic tube with activated carbon, and the mouth of the tube should be wax sealed.
  5. Moisture-proof
  6. Bleaching powder and sodium peroxide should be sealed to prevent water-absorbing decomposition or water-absorbing explosion. Sodium hydroxide is easy to absorb water and deliquesce, so it should be sealed. Ammonium nitrate and sodium sulfate are easy to absorb water and can not be poured out, which may cause the reagent bottle to rupture. They should also be sealed tightly.
  7. Calcium carbide, anhydrous copper sulfate, phosphorous pentoxide, silica gel are easy to absorb water and deteriorate, and red phosphorus is easily oxidized. Then, it absorbs water to generate metaphosphoric acid. All of the above should be stored in a desiccator.
  8. Although concentrated sulfuric acid should be airtight to prevent water absorption, it should be placed in a ground-mouth bottle because it is commonly used.
  9. In the basement of “special medicine”, the lower layer of cloth is ash, the middle layer is clothed with slaked lime and the upper layer is clothed with double-layer tar paper before the medicine can be stored.

Three, prevent deterioration

  1. Anti-oxidation: Sodium sulfite, ferrous sulfate, and sodium thiosulfate are all easily oxidized, and the bottle mouth should be coated with wax.
  2. Anti-carbonation: Sodium silicate, sodium peroxide and caustic are all easy to absorb carbon dioxide and should be coated with wax.
  3. Weatherproofing: Crystal sodium carbonate and crystal copper sulfate should be sealed and stored in the basement.
  4. Anti-decomposition: Ammonium bicarbonate and concentrated nitric acid are easy to decompose when heated, and store in the basement after wax coating.
  5. Activated carbon can absorb a variety of gases and deteriorate, (charcoal is also the same), so it should be placed in a desiccator.
  6. Yellow phosphorus is easy to ignite spontaneously in contact with air. Keep it in the water forever. Check the water every 15 days: add water to the phosphorus reagent bottle, place it in the water-containing drain, and seal it with a bell.
  7. Potassium and sodium are stored in kerosene.
  8. Add a few drops of dilute sulfuric acid to the ferrous sulfate solution, add excess fine iron powder, and wax seal.
  9. Glucose solution is prone to mildew, just add a few drops of formaldehyde to save it.
  10. Formaldehyde is easy to polymerize. A small amount of methanol should be added immediately after opening the bottle; ethanol should be added to acetaldehyde.

Four, anti-light

  1. Silver nitrate, concentrated nitric acid and most organic drugs should be placed in brown bottles;
  2. Nitrate is stored in the basement to prevent heat, light, fire and shock;
  3. All display windows of organic reagents are painted with black paint;
  4. Colored cloth curtains for laboratory use, double-layer inner infrared black;

Five, anti-poisoning

  1. Phosphorus, silver nitrate, potassium chlorate, mercury chloride and other highly toxic substances are placed in the basement, double-locked for two persons, archives are established, submitted for approval, use records, and regular inspections.
  2. Calcium phosphide and aluminum phosphide release highly toxic phosphine after absorbing water. They should be stored in a desiccator and labeled with a red label.
  3. Because there is no fume hood, lime is often placed on the ground to adsorb certain poisonous gas phase substances.
  4. For corrosive drugs such as concentrated acid, concentrated alkali, bromine, phenol, etc., red labels are used as a warning.

Sixth, shockproof

  1. Ammonium nitrate is easy to explode when shaken, so put it in the basement.
  2. Homemade large crystal alum and large crystal copper sulfate are packed in a large-mouth reagent bottle with a soft paper pad, buffered, and numbered into the kitchen according to the “four-digit number”.

Seven, fire prevention

  1. Set up a water tank, fire bucket, sand tank, foam fire extinguisher and a bottle of carbon tetrachloride in the “door”, “conspicuous”, and “easy” place of the instrument room. Foam fire extinguisher medicine is renewed once a year. (If there is a “CCl4” or “1211” fire extinguisher, it is better).
  2. All indoor wires shall be replaced with dark wires to prevent fumigation of drugs, short circuit and fire escape.
  3. Anti-rat
  4. Properly adjust more phenol in the paste.
  5. For the “indicator” medicine, put some volatile medicines such as formaldehyde, cresol soap, etc. In a cabinet with severe rodent damage, concentrated hydrochloric acid and concentrated ammonia can be alternately stored. Used to protect other medicines.
  6. Apply lead acetate paste on the four walls of the mouth of the mouse. When the mouse enters and exits, it will contaminate the skin, lick and kill (lead acetate is sweet and highly toxic).

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