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| GENERAL
CLEANING |
1. |
Cleaning of
glassware which has contained hazardous materials
must be solely undertaken by experienced personal. |
2. |
Most new glassware is slightly
alkaline in reaction. For precision chemical tests,
new glassware should be soaked several hours in
acid water (1 % solution hydrochloric acid or
nitric acid) before washing. |
3. |
Glassware which is contaminated
with blood clots, culture media, etc. must be
sterilized before cleaning. |
4. |
If glassware become induly
clouded or dirty or contains coagulated organic
matter, it must be cleaned with chromic acid cleaning
solution. The dichromate’s should be handle
with extreme care because it is a powerful corrosive |
5. |
Wash glassware as quickly
as possible after use but if delays are unavoidable,
the articles should be allowed to soak in water.
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6. |
Grease is removed by weak
sodium carbonate solution or acetone or fat solvents.
Never use strong alkalis.
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7. |
Hot water with recommended
detergents should be used and if glass is exceptionally
dirty a cleaning power with a mild abrasive action
can be applied, provided the surface is not scratched. |
8. |
During washing all parts
of the article should be throughly scrubbed with
a brush selected for the shape and size of the
glassware. Brushes should always be in good condition
to avoid any abrasion of glassware. |
9. |
When chromic acid solution
is used, the item may be rinsed with the cleaning
solution or it may be filled and allowed to stand.
The amount of time should depend on amount of
contamination on the glassware. |
| 10. |
Special type of precipitate material may required
removal with nitric acid, aqua regia or fuming sulphuric
acid. These are very corrosive substances and should
be used only when required. |
| 11. |
It is imperative that all soap detergents and
other cleaning fluids be removed from glassware
before use. This is especially important with the
detergents, slight traces of which will interfere
with serologic and culture reactions. After cleaning,
thoroughly rinse with tap water ensuring that containers
are partly filled with water, shaken and emptied
several times. Finally rinse with deionised or distilled
water. |
| 12. |
Drying can be undertaken either in baskets or
on pages in air or at a temperature not exceeding
120°C. |
| 13. |
Always protect clean glassware from dust by use
of temporary closures or by placing in a dust free
cabinet. For cleaning specific type of glassware,
please refer the following pages. |
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| Cleaning
Specific Types of Glassware |
1. |
Pipettes
Place pipettes tips down, in a cylinder or tall
jar of water immediately after use. Do not drop
them into the jar, since this may break or chip
the tips and render the pipettes useless for accurate
measurements. A pad of cotton or glass wool at
the bottom of the jar will help to prevent breaking
of the tips. Be certain that the water level is
high enough to immerse the greater portion or
all or each pipette. At a convenient time, the
pipettes may then be drained and placed and in
a cylinder or jar of dissolved detergent or, if
exceptionally dirty, in a jar of chromic acid
cleaning solution. After soaking for several hours,
or overnight, drain the pipettes and run tap water
over and through then until all traces of dirt
are removed. Soak the pipettes in distilled water
for at least one hour. Remove from the distilled
water, dry the outside with a cloth, shake out
the water and dry.
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| Burettes
(with glass stopcock) |
1. |
Remove the stopcock
key and wash the burette with detergent and water.
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| 2. |
Rinse with tap water until all the dirt is removed.
Then rinse with distilled water and dry. |
| 3. |
Wash the stopcock key separately. Before the stopcock
key is replaced in the buretts stopcock key are
not interchangeable |
| 4. |
Always cover burettes when not in use. |
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| Culture
Tubes |
1. |
Culture tubes
which have been used previously must be sterilized
before cleaning. The best general method for sterilising
culture tubes is by autoclaving for 30 minutes
at 121°C (15ib. pressure). Media which solidify
on cooling should be poured out while the tubes
are emptied, brush with detergent and water, rinse
throughly with tap water, rinse with distilled
water, place in a basket and dry. |
| 2. |
If tubes are to be filled with a medium which
is sterilized by autoclaving, do not plug until
the medium is added .Both medium & tubes are
thus sterilized with one autoclave. |
| 3. |
If the tubes are to be filled with a sterile medium
or if they are to be sterilized by the fractional
method then sterilize the tubes in the autoclave
or dry air sterilizer before adding the medium.
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| Serological
Tube |
1. |
Serological
Tubes should be chemically clean but need not
be sterile. However, specimens of blood which
are to be kept for some time at room temperature
should be collected in a sterile container. It
may be expendient to sterilize all tubes as routine. |
| 2. |
To clean and sterilize tubes containing blood,
discard the clots in a waste container and place
the tubes in a large basket. Put the basket, with
others, in a large bucket or boiler. Cover with
water, add a fair quantity of soap or detergent
and boil for 30 minutes. Rinse the tubes and clean
with brush, rinse and dry with the usual precautions. |
| 3. |
It is imperative when washing serological glassware
that all acid, alkali and detergent be completely
removed, Both acid and alkali in small amounts destroy
complement and in large amounts produce hemolysis.
Detergents interfere with s e r o I o g i c reactions. |
| 4. |
Serological tubes and glassware should be kept
separate from all other glassware and used for nothing
except serologic procedures. |
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