Washing, Drying, And Sterilization Of Glassware (pgs 504)

Washing, Drying, And Sterilization Of Glassware (pgs 504)
Basic concept of laboratory technique

1. INDIRA GANDHI KRISHI VISHWAVIDYALAYA RAIPUR AN ASSIGNMENT ON WASHING, DRYING, AND STERILIZATION OF GLASSWARE COURSE TITLE – BASIC CONCEPT IN LABORATORY TECHNIQUES COURSE NO - PGS – 504 SUBMITTED TO SUBMITTED BY DR. ANURAG SANJAY KUMAR DEPT. OF SOIL SCIENCE M.Sc.(Hort.) Pre. Year 2 nd sem. COA RAIPUR Dept. Of Floriculture

2. GLASSWARE Laboratory glassware refers to various items which are usually made of glass and used for scientific work in chemistry and biology laboratories. ... Pipettes, petri dishes, and test tubes are examples of laboratory glassware. Glassware Falls Into The Following Categories: Pyrex consists of borosilicate. Borosilicate glass is free of zinc and heavy metals. These resist heat, corrosion, and thermal damage. These are very good for heating and sterilization. 2. Corex consists of aluminosilicate. These are made strong chemically rather by heat. These are 6 times stronger than borosilicate glass.These are resistant to alkali and scratching. This glass can withstand high heat >250 °C.Examples are cylinders and centrifuge tubes.

3. 3. High silica like Vycor is acid and alkali resistant. These can withstand high temperatures (heat shock).It can withstand extremes of acids and alkali. These can be heated to 900 °C. These can withstand heat shock from 900 C to 0 °C. 4. The low actinic glass is amber-colored. These are amber or red color glass. Protects the serum from light. Used to handle bilirubin, carotene, and vitamin A. 5. Flint glass has a high index of refraction. These are soda-lime glass consisting of silicon, calcium, and sodium oxide.These are the cheapest of all.These are not resistant to high temperatures. It cannot tolerate heat shock.Resistant to the chemical is not strong.This glass is easy to melt and shape it.

4. Washing Of Glassware Used For Organic Chemistry: Rinse the glassware with the appropriate solvent. Use deionized water for water-soluble contents. Use ethanol for ethanol-soluble contents, followed by rinses in deionized water. Rinse with other solvents as needed, followed by ethanol and finally deionized water.If the glassware requires scrubbing, scrub with a brush using hot soapy water, rinse thoroughly with tap water, followed by rinses with deionized water Washing With Soap And Water: Soak the glassware in soap solution for at least 10 to 15 minutes or leave overnight. Scrub with brush or cloth or sponge if needed. Rinse thoroughly with tap water.Again rinse with distilled or deionized water.If you need soon this glassware then rinse with acetone or ethanol. Burets (Cleaning) Wash with hot soapy water, rinse thoroughly with tap water. Then rinse 3-4 times with deionized water.Burets need to be thoroughly clean to be used for quantitative lab work. Pipets And Volumetric Flasks (Cleaning) May need to soak the glassware overnight in soapy water. Clean pipette and volumetric flasks using warm soapy water. The glassware may require scrubbing with a brush.Rinse with tap water followed by 3 – 4 rinses with deionized water.

5. Drying Of Glassware If glassware is to be used immediately after washing and must be dry. Rinse it 2-3 times with acetone. This will remove any water and will evaporate quickly. This is not a great idea to blow air into glassware to dry it. Acetone may be used for a final rinse of sensitive or urgently needed glassware as the solvent is miscible with water, and helps dilute and wash away remaining water from the glassware. Wash Labware As Quickly As Possible After Use: If a thorough cleaning is not possible immediately, put glassware to soak in water.If labware is not cleaned immediately, it may become impossible to remove the residue. Put into acid water (a 1% solution of hydrochloric or nitric acid) before washing. Can keep for several hours in this solution.Brushes with wooden or plastic handles are recommended as they will not scratch or abrade the glass surface. Chromic Acid Use: If glassware becomes unduly clouded or dirty or contains coagulated organic matter, it must be cleaned with chromic acid. When the chromic acid solution is used the item may be rinsed with the cleaning solution or it may be filled and allowed to stand. Time depends on the amount of contamination on the glassware. Relatively clean glassware may require only a few minutes.If more contaminated then keep overnight.Special types of precipitates may require removal with nitric acid or sulfuric acid.

6. Hematological Glassware Needs Special Precautions: Do not use detergents because if there is a minute concentration that may lead to hemolysis of RBCs. So for general Tubes, pipettes, and slides wash these thoroughly under tap water. Can use a brush to remove any leftover from the glassware. Keep the hematology used material in a dichromate solution for 12 to 24 hours. Then again wash thoroughly with tap water. Allow draining. Dry in the hot oven. Blood Pipettes Need The Following Method To Clean: With the help of a suction pump or handheld suction pump, draw tap water through these pipettes. Use distilled water for suction and washing.Last can use acetone for the same purpose.Let them dry in the air. If there are blood microclots then keep them in 10% potassium hydroxide for 12 to 24 hours. Conclusion And Important Facts: Glassware should be cleaned as soon as possible.In the case of delay, put the glassware in water.In the case of late cleaning, the residue may not be possible to remove. New glassware which is slightly alkaline needs to be soaked in acid water (1% HCl or HNO3) for several hours before washing.

7. Sterilization Of Glassware The sterilization can be done by following methods: Dry Heat sterilization has limited value. Prolonged exposure may cause damage. Hot air oven where heat is transferred by convection, conduction or radiation. The temperature of 100 °C for one hour can destroy the nonsporing organism. Fungal spores need 115 °C for one hour. While for other all bacteria at 160 °C temperature is needed for one hour. Incineration where the flame is an effective way of sterilization. Flame heat is needed for the loop for culture. Moist heat is the most reliable method of sterilization. This is the most lethal agent to kill microorganisms. Microbial death is due to coagulation and denaturation of the protein and enzyme. Boiling is not effective to kill spore-bearing bacteria and for surgical instruments. Steam sterilization or Tyndallization is exposure to steam at 100 °C for 90 minutes. This good means to sterile the media which contain sugar.

8. The autoclave is heating water under pressure which boils at progressively higher temperatures. This method is good for rubber material and surgical instruments. Membrane filters are Millipore filters. Filters with a pore of 0.22 micrometers are sufficient for the bacteria. Seitz filter is a disposable asbestos pad filter. Flaming when the material is wetted by alcohol and then flamed. This method is rapid. Ultraviolet light causes damage to bacteria. Radiation in the form of beta and gamma X Rays used for surgical pads. Supersonic and ultrasonic waves, 9000 cycles per second or above are used to rupture and disintegration of the cells.

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