Greetings to Primum Mobiles of the suscitate art of CS.
Cleaning and sterilyzing glass is a good thing to do. Here is how it
was done when Lab people had a healthy fear of dangerous microbes.
Taken from Practical Bacteriology, Blood Work and Animal Parasitology,
By E.R.Stitt,A.B.,Ph.G.,M.D. Sc.D.,LL.D.,President National Board of
Medical Examiners, Surgeon General of U.S. Navy, etc.,etc..(guess he
knows what he`s talking about).
Cleaning Glassware
It is routine in our laboratory for everything to go through the
sterilizer at 125 C before anything else is done. This is a safe rule
when dealing with dangerous pathogenic organisms (especially tetnus and
anthrax).
Note: Instruction begins with used and contaminated
glassware,containing faeces,sputum, blood, tissue, etc..
As soon as the tubes or dishes are taken out of the sterilizer they are
emptied of their contents and placed in a 1% solution of washing soda
and boiled. This thoroughly cleans them. As the washing soda slightly
raises the boiling-point of the solution and also makes the spores more
penetrable. It would be sufficient to place all contaminated articles in
a dishpan with the soda solution, and boil for at least one hour,
omitting the preliminary sterilization in the autoclave.
The tubes are next cleaned with a test-tube brush, throughly rinsed
with tap water and placed in a 1% solution of hydrochloric acid for a
few minutes; then rinsed throughly in water and placed in test tube
baskets, mouth downward, and allowed to drain over night. Some
laboratory workers boil their test tubes and other glassware in water
containing soap or soap powder and, after a through rinsing in tap
water, drain. Hydrochloric acid should not be used after the soap as it
will cause the formation of an unsightly coating difficult to remove.
When throughly dry, tubes may be plugged and sterilized.
Cleaning Fluid.-- A cleaning fluid commonly used in laboratories
consists of one part each of potassium bichromate and commercial
sulphuric acid with ten parts of water. This is an excellent mixture for
cleaning old slides, etc., especially when grease or balsam is to be
removed. It is very corrosive, however.
In cleaning glassware for such tests as the colloidal gold it is
essential that we use such a cleaning fluid. An efficient and less
corrosive method for cleansing slides and cover glasses is to leave them
over night in an acetic acid-alcohol mixture (two parts of glacial
acetic acid to 100 parts of alcohol). After removing slides and glasses
from this mixture, they are dried and polished; in addition, it is well
to pass them through the flame of a Bunsen burner or alcohol lamp to
remove every vestige of grease. The cover glasses should be exposed only
momentarily to the flame to avoid warping. Ordinarily, rubbing between
the thumb and forefinger with soap and water, then drying with an old
piece of linen, and finally flaming will yield a perfect surface for
making a bacterial preparation.
An excellent cleaning disinfectant is Liquor cresolis comp.,U.S.P.,
which has a phenol coefficient of 1.87 to 3. A 5% solution is useful as
a desk-jar disinfectant and in treating faeces,sputum, etc..
----end----
Interesting from General Chemistry by Petrucci.
Chromate-Dichromate--CrO3
CrO3 is obtained by the action of concentrated sulfuric acid on a
chromate or dichromate. This red solid is a powerful oxidizing agent
and, in conjunction with concentrated sulfuric acid is commonly used as
a "cleaning solution" for laboratory glassware. Its principal mode of
action is to oxidize grease.
----end---
Food for thought
bless you Bob Lee
--
oozing on the muggy shore of the gulf coast
[email protected]
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