1/07/2024

Introduction
Water is essential for human life.Water pollution is a significant environmental issue.Due to pollution water supply sources get polluted with harmful micro-organisms. Contaminated water can lead to waterborne diseases, such as cholera, typhoid, and dysentery.

What is the H2S Strip Test?

H2S test performs to check the microbial contamination in water.

It is quick and qualitative test.

Sterilization Processes of plastic H2S bottles :

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  1. Bottles washing with detergent.
  2. Rinse with tap water.
  3. Soaked in 5% bleach solution for 8 hours.
  4. Rinse with tap water.
  5. Dry in hot air oven at 50°C for 4-5 hrs.

Media Preparation for the strip :

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Prepare Media for 50 ml

Name of chemical        Qty. in gm/ml
Bacteriological grade pepton             20gm
Di potassium hydrogen phosphate             1.5gm
Ferric ammonium citrate             0.75gm
Sodium Thiosulphate             1.0gm
L- cysteine HCL             0.125gm
Liquid soap              1.0ml
Distilled water              50 ml

Step-1: Clean the glassware.

Step-2: Dissolve above mentioned chemicals in Distilled water.

Step-3: Stir until powder media is completely soluble in water. Dark Amber colour solution is formed.

Step-4: pH should be maintained between 6.5 to 7.2

Media is ready to use.

The procedure of the H2S Strip Test:

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Note: Step- 1, Step-2, Step-4, Step-5 perform in asceptic condition.

For Maintaining aceptic condition: clean LAF (laminar air flow) using aceton / 80% ethanol and ON UV light for 15-20 mi. After 20 min OFF UV light and ON blower and day light.

Step-1: Take absorbent paper i.e. Whatman Filter paper No.- 41 cut the paper in size 8*2.5 CM for making per strip then dip the strip into media with the  help of forecep for 10-20 sec

Step-2:  fold the strip in sterile petri plate with the help of forecep.

Step-3: Dry the paper strips in hot air oven at 55 degrees Celsius for 30 min.

Step-4: After drying, keep it in a dry sterilized container i. e plastic bottle.

Step-5: While using strips keep it in the sterilized container and add the sample.

Step-6: Incubate at room temperature for 48 hrs.

Observation:

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The blackening of samples denotes the presence of microbial contamination.Distilled water shows test positive

As per observation each sample takes different time gap.

Conclusion:

Result is not proper. It shows dissimilar than standard kit.

We identified an error in our previous procedure that we’re working to correct.