Cleaning Procedure for all glassware Essay
Cleaning Procedure for all glassware, 473 words essay example
Essay Topic: environmental, time, green, solution
2.4.2 Cleaning Procedure for all glassware
Using ethanol on a paper tissue to remove any markings and labels.
Rinse three times with tap water in washbasin.
Rinse three times with milli-q water.
Rinse at least three times with 5050 HNO3Milli-Q water cleaning solution.
Rinse three times with Milli-Q Water.
Allow air dry on drying rack.
2.4.3. Cleaning procedure for new pipette tips and centrifuge tubes
Rinse in Milli-q Water in large plastic container.
Place in 5050 Hno3 Milli- q water cleaning solution in large beaker in fumecupboard for 24 hrs.
Place in Milli-Q water in large glass beaker for 24 hours.
Rinse three times with Milli-Q water.
Dry in oven 60OC until dry.
It should be noted that all cleaning solutions (Milli-q water and 5050 HNO3Milli Q water) should be regularly replaced.
2.5 Preparation of Chromic Acid Solution
Chromic Acid Solution of CrO3 in concentrated H2SO4. A premeasured mix is available under the name of "chromerge", which should be treated in the same ways as aqua regia or acidic peroxide solutions. Because high valent chromium is carcinogenic and teratogenic it may cause severe environmental damage. The use of chromic acid is not recommended. Hydrofluoric acid concentrated solutions of HF will remove just about everything from glassware and then may etch the glass surface also.It should not be used on calibrated volumetric. Hydrofluoric acid causes severe painful burns that may not heal well and prolonged or intense exposure can lead to a very slow or painful death.
To prepare a chromic acid solution following steps are to be followed
Mix 20 gm of sodium or potassium chromate with sufficient distilled water to make a paste of chromate salt.
Add 300 ml of concentrated sulphuric acid
Make larger amount by increasing the proportions
Use the mixture until it is green in colour.
Soak the apparatus needed to be clean depend on the type of solution.
Storage of Chemicals
For storage of chemicals some basic requirements are
Label storage area according to type of chemical family.
Label all the chemicals
Inspect the chemical storage area time to time.
Keep storage area well lighted as well as properly ventilated.
Ignition sources such as open flames, direct heat should be away from sunlight.
Keep emergency equipments such as fire extinguisher handy, so can be used in case of emergency.
Confinement of area is necessary so that leaks or spills can be controlled. In case of sudden spill, clean the area immediately.
The shelves should be properly labelled, levelled, secured to the wall.
Shelves should be free from dust and any other contamination, which may cause accidental damage to the lab.
Store large bottles not higher than 2 feet from the floor. Store corrosive on the lower shelves.
Use only approved storage cabinets.
Don't store chemicals in sink.
Don't keep the hazardous chemicals unlabelled.
Don't store chemicals on floors, balconies or on window ledges.
Keep the containers tightly closed, and do not open them unnecessarily.