Thursday, December 26, 2019

Cleaning of glassware

  Many of the  previously used glassware are replaced by  plastic  material which are  used once and disposed which makes  contamination less likely and  also reduces the need for  cleaning  but  the techb nician should be  knowledgeable about glassware as some  uses still require them and if you are working  in a remote  resource  deficient area  they may be  the  only things available to you.Cleaning of glassware
A . New glassware should first be examined for obvious flaws and cracks.
They should be soaked in 2% Hydrochloric acid overnight to neutralize an alkali
present. They are then washed in running water until all traces of acid have gone.
They are then boiled in a synthetic detergent for 30 minutes, rinsed thoroughly
in running tap water and finally in distilled water. Then the glassware may be
dried in oven at a temperature not exceeding 80 degree centigrade
B. Used glassware should be rinsed out immediately after use. They

should then be boiled in a for 30 mins. and thoroughly scrubbed Wilh a
test tube brush, rinsed in running tap water and finally in a distilled water and
dried as above. Stained glassware may be soaked overnight in dichromate
solution, washed in tap water and rinsed in a distilled water. Dichromate is the
most satisfactory method of cleaning pipettes and dirty glassware as it removes
all traces of grease.

  Dichromate cleaning solution
cleaning solution
Dissolve 25 gm potassium dichromate in 25 ml. water. Slowly, add with
stirring, 50 ml conc. H2S04 (always add to water and not vice versa). When
cool, store solution in a stoppered bottle.
Specialized Apparatus
Petri dishes
They should be thoroughly washed in soapy water after autoclaving to remove
infected material. They should then rinsed in running water and stacked to dry.
When it is almost dry, they can be rinsed with methylated spirit and left to dry
completely, then matched up for sterilizing by hot air.
Soak in chromic acid overnight, wash in running water and dry on suction
pump, using meth-spirit / ether or acetone. To sterilize plug mouth piece with a
non—absorbent cotton wool, wrap in craft paper and hot air sterilize (1600C for
I hour).

After autoclaving to remove infected material, tubes are boiled in detergent
solution for 30 mins, rinsed in running water, distilled water and finally placed
in wire basket and hot air sterilized after plugging them with a non-absorbent
cotton wool.

Pasteur pipettes should be soaked in 3% Lysol at least for 1 hr. and then
Washed as before.

Glass slides

New slides should be boiled in detergent for 30 mins and washed
with running water. They are placed in dichromate overnight and
 washed again in running water and rinsed in distilled water and stored in methylated spirit. When required, the slides are removed and dried on a clean soft Cloth. This procedure will make the slides completely grease—free. Sterilization use and care of syringes As syringes play an important part in the clinical pathology laboratory, particular care must be given to Their use and sterilization. Complete bacterial sterility can be achieved only by sterilization in the hot air oven autoclave. Injection syringes and needles must be kept separate from those used to draw blood, ideally a fresh syringe and needle should be used for each injection. For drawing blood, a fresh syringe and a needle must be for each patient. Now-a-days, disposable syringes of differed capacities and needles of different sizes are widely used in private clinical laboratories in order to avoid chances of carrying any indirection due to rc-used needles. Syringes should be of good quality glass so that they do not break easily. Sizes 2, 5, 10, 20.30 ml are kept for drawing blood and I ml for injection. Needle should be of best quality With sharp points, made of stainless steel combining strength and flexibility and highly resistant to corrosion. Needles of size 19 or 20 SWG arc best for drawing blood. Si7ß 18 may be used where a large amount is needed. Size 21 is used in children.

 Basic instrumental requirements

The technician as he commences his course of training will find himself handling expensive, and often delicate instruments which if handled properly will be invaluable 10 him and 10 his work and will last a life—time. Some of the more important instruments are considered which arc as follows : 1. Microscope, 4. Hot air oven. 7. Autoclave, 1. 2. Calorrmeter, 5. Incubator, 8. Physical balance 3. Centrifuge, 6. Water bath 9. Refrigerator. The word 'microscope' is derived from  two Greek words 'micro' meaning small and 'scope' meaning to view. In Other words, a microscope is an instrument used for the visual examination of small objects which cannot be examined properly by the naked eyes. lt is a complicated instrument with different fitted in each other very accurately. The eyepiece fits into a graduated tube which in turn slides into the body tube. A revolving nose piece is attached to the lower end of the body you and to it, various objectives arc fixed. The body tube and objectives arc moved up and down by means of a screw of a rack and pinion mechanism known as
known as the coarse adjustment . The tube and its attachments are connected to the foot of
hinged joint. Below the objective, is the stage of microscope on which the preparations are mounted.





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