Among the types of water commonly used in a medical laboratory,Distilled water is one of the most used water in carrying out biological analysis other from deionised water,Tap water etc..

Distilled water is water that has been converted to steam or  gas vapour through boiling then cooled or condensed back to liquid water.It is one type of purified water free from minerals salts.

In a medical laboratory,Distilled water is very important and knowing how to locally and manually prepare distilled water is a surplus.Laboratory manager with limited budget can use this method to get distilled water at no cost and reallocate finance to other important laboratory asset rather than spending on buying already prepared distilled water.

Principle of Water distillation

• Based on the change of state of water from Water to water vapour by evaporation and condensation back to water when boiled.
• As the water boils it becomes steam or water vapour  which hit the cold lid of the pot and be cooled down to become water again. Some of the water will obviously drip into the glass bowl. That’s the distilled water.

Here’s how to make a scaled distilled water with the available material.

Materials needed

• A 10 to 20 litres of  stainless-steel pot with a stainless-steel cover but you can use any clean stainless pot depending on the volume of distilled water to be made with a lid or cover of course
• Tap water
• A heat resistant glass bowl
• Baking rack (Optional) if you have a fitting heat resistant glass bowl
• Ice cubes

Procedure in Preparing Distilled Water

• Put the baking rack on the bottom of the stainless-steel pot.This will act as a supportive frame for the glass bowl
• Now fill the pot halfway with tap water.
• Insert the  the glass bowl in the pot, so that it floats on the surface of the  tap water.Note that the baking rack should ensure that the bottom of the glass bowl doesn’t touch the pot or the bottom of the pot as illustrated below.
• Now turn the pot cover upside down and place it on top of the pot.
• Then fill the inverted pot cover with ice cubes.
• Bring the water to a boil for about 45 minutes, replacing the ice as necessary.
• After recovering the quantity of distilled water needed,turn off the gas then remove the lid from the pot
• Using clean gloves, remove the glass bowl carefully.Note that it will be very hot
• Then allow the distilled water in the bowl to cool down before transfering in clean bottles or containers for future uses

Uses of Distilled water

Note that distilled water does not contain other components that may affect the results a laboratory experiment. It is pure water is useful in the following procedures in a medical laboratory

• Preparation of Culture media
• In the dillution of samples and reagent
• Preparation of reagent and many more

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• Image source :  instructables  
• Reference :howstuffworks