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Preparation and precautions of glass instrument washing liquid
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Preparation and precautions of glass instrument washing liquid

Views:0     Author:Site Editor     Publish Time: 2020-09-15      Origin:Site

Washing liquid is abbreviated as washing liquid, and there are various kinds of washing liquid according to different requirements. The more commonly used ones are introduced as follows.


1. Strong acid oxidizer lotion


Strong acid oxidizer lotion is made of methyl dichromate (K2Cr2O7) and concentrated sulfuric acid (H2SO4). K2Cr2O7 has strong oxidizing ability in acid solution, and has little corrosive effect on glass instruments. So this kind of lotion is most widely used in the laboratory.


The concentration of preparation varies from 5 to 12%. The preparation method is roughly the same: take a certain amount of K2Cr2O7 (industrial products can be), first use about 1 to 2 times of water to dissolve, after a little cold, slowly add the required volume of industrial product H2SO4 into the K2Cr2O7 insoluble solution (thousands Never add water or solution to H2SO4), stir with a glass rod while pouring, and be careful not to spill, mix well, and after cooling, put it into the lotion bottle for use. The newly prepared lotion is reddish brown and has strong oxidizing ability. When the lotion turns to black and green after a long time, it means that the lotion has no oxidative washing power.

Laboratory glassware

For example, prepare 500mL of 12% lotion. Take 60 g of industrial product K2Cr2O7 and place it in 100 mL of water (the amount of water added is not fixed, but to be soluble), heat to dissolve, cool, slowly add concentrated H2SO4340 mL, stir while adding, and bottle it after cooling.


When using this lotion, be careful not to splash it on your body to prevent “burning” clothes and damaging the skin. Pour the lotion into the instrument to be washed, so that the surrounding wall of the instrument should be completely immersed and then stop for a while and then pour it back into the lotion bottle. After rinsing the instrument that has just been immersed with a small amount of water for the first time, do not pour waste water into the pool and sewer. It will corrode the pool and sewer for a long time. It should be poured into the waste tank. When the tank is full, pour it into the garbage. Waste liquid tank, age-oriented literacy, immortal outlook on life, hormonal talk method when entering the pool, flush it with plenty of water while pouring it.


2. Alkaline lotion


Alkaline lotion is used to wash instruments with greasy dirt. This lotion is used for a long time (more than 24 hours) soaking method or a dipping method. When picking up the instrument from the alkaline lotion, wear latex gloves to avoid burns to the skin.


Commonly used alkaline washing solutions include: sodium carbonate solution (Na2CO3, soda ash), sodium bicarbonate (Na2HCO3, baking soda), sodium phosphate (Na3PO4, trisodium phosphate) solution, disodium hydrogen phosphate (Na2HPO4) solution and so on.


3. Alkaline potassium permanganate lotion


Using alkaline potassium permanganate as a lotion, the effect is slow, suitable for washing greasy utensils. Preparation method: Take 4 grams of potassium permanganate (KMnO4) and dissolve it in a small amount of water, then add 100 mL of 10% sodium hydroxide (NaOH).


4. Pure acid and soda ash lotion


According to the nature of the dirt on the utensils, directly soak or soak the utensils with concentrated sulfuric acid (HCL) or concentrated sulfuric acid (H2SO4) or concentrated nitric acid (HNO3) (the temperature should not be too high, otherwise the concentrated acid volatilizes and irritates people). Soda ash lotion usually uses more than 10% concentrated caustic soda (NaOH), potassium hydroxide (KOH) or sodium carbonate (Na2CO3) liquid soaking or soaking utensils (boiling can be used).

Laboratory glassware

5. Organic solvents


Utensils with fatty contaminants can be scrubbed or soaked with gasoline, toluene, xylene, acetone, alcohol, chloroform, * and other organic solvents. However, using organic solvents as a lotion is more wasteful, and large instruments that can be cleaned with a brush should use alkaline lotions as much as possible. Only small parts or special-shaped instruments that cannot be used with brushes should be washed with organic solvents, such as piston bores, pipette tips, burette tips, burette piston holes, droppers, vials, etc.


6. Decontamination liquid


The utensils used for testing carcinogenic chemicals should be soaked in a decontamination solution that has the destructive and decomposing effect of these carcinogenic substances before washing in order to prevent harm to the human body, and then wash them.


The decontamination solutions often used in food inspection are: 1% or 5% sodium hypochlorite (NaOCL) solution, 20% HNO3 and 2%KMnO4 solution.


1% or 5% NaOCL solution has a destructive effect on aflatoxin. After soaking the contaminated glass instrument with 1% NaOCL solution for half a day or soaking with 5% NaOCL solution for a while, the aflatoxin can be destroyed. Preparation method: Take 100 grams of bleaching powder, add 500 mL of water, and stir evenly. Dissolve 80 grams of industrial Na2CO3 in 500 mL of warm water, mix the two liquids, stir, and filter after clarification. The filtrate contains 2.5% NaOCL; if used For the preparation of bleaching powder, the weight of NaCO3 should be doubled, and the concentration of the resulting solution is about 5%. If 1% NaOCL solution is needed, the above solution can be diluted proportionally.


20% HNO3 solution and 2% KMnO4 solution have a destructive effect on benzo(a)pyrene. Glass instruments contaminated with benzo(a)pyrene can be soaked in 20% HNO3 for 24 hours. After taking it out, wash away the remaining acid with tap water. Perform washing. Latex gloves and micro syringes contaminated by benzo(a)pyrene can be soaked in 2% KMnO4 solution for 2 hours before washing.


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