Maintaining proper hand and respiratory hygiene plays an important role in the fight against COVID-19. To achieve this, hand sanitisers and masks are essential. However, even as we wonder at the effectiveness of a hand sanitiser, fake products have flooded the market, risking thousands of lives. So is there a way to check the quality?
Yes, there are certain cost-effective ways to ensure the quality, as suggested by Dr Saurabh Arora, founder, http://www.Testing-lab.com.
What you need
*Tissue paper roll (toilet paper)
*Ballpoint pen – Make sure the ballpoint pen you use for conducting this test is not water washable. Do not use a gel or ink pen.
*Anything with which you can draw a small circle, such as a coin or even the cap of your sanitiser bottle can work just fine.
*Half cup of wheat flour
*Some plates and bowls
The Tissue Paper or Toilet Paper Test
*Take a small piece of tissue paper and keep it on a flat surface. It is important you do not make a thick wad of the tissue paper as you want the sanitiser to defuse sideways only and not down into the tissue paper.
*Use a ballpoint pen and carefully draw a circle on the paper by outlining a coin or the cap of the hand sanitiser bottle. Make sure the line is continuous, thick and clear.
*Place a few drops of the hand sanitiser liquid or gel in the middle of the circle. Be careful not to pour too much sanitiser that it overruns the line, nor should it be too little that it doesn’t diffuse past the line.
*Let the hand sanitiser slowly diffuse and move out of the circle. The liquid sanitiser will diffuse almost instantly while the gel-based will take some time.
*You can also repeat this with a little bit of water to see how a fake sanitiser without alcohol behaves.
If the sanitiser contains sufficient quantity of alcohol, you will see that the line you had drawn with the ballpoint pen will dissolve in the sanitiser and the colour starts to spread out. However, if the sanitiser does not contain the required quantity of alcohol, the line will not be dissolved and the sanitiser will just defuse past the line without any change.
How does it work?
This simple test is based on the principle of paper chromatography. The ink which is used in water-resistant ballpoint pen does not dissolve in water but very quickly dissolves in alcohol. This causes the ink to move along the front of the diffusing sanitiser and spreading out. If the alcohol content is less, the solubility of the ink is not sufficient and the line doesn’t move.
The Wheat Flour Dough Test
*Take one tablespoon of wheat flour on a plate. You can also take maize or other flour that quickly forms a dough with water.
*Add one tablespoon of the sanitiser you want to test. Do not add too much of the sanitiser.
*Knead the flour and the sanitiser together to make a dough.
If the sanitiser contains an excess amount of water, the flour will quickly become sticky and eventually turn into a dough. If it contains the right amount of alcohol, the flour will not become sticky and remain as a powder and eventually the sanitiser will dry up.
How does it work?
This test is based on the simple fact that flour needs water for the gluten and carbohydrates to swell and become sticky and turn into dough. Alcohol, on the other hand, competes with the gluten and carbohydrates for the water molecules and won’t let them hydrate and become sticky. This test is very sensitive and can easily detect samples with 60 per cent or less of alcohol.
The Hair Dryer Test
*Take one tablespoon of the sanitiser in a small bowl.
*In another bowl, take some water.
*Using a hair dryer, dry the sanitiser for 30 seconds. Make sure to let the hair dryer heat up before you start.
*In the same way and at the same temperature, dry the water.
If the sanitiser has the required amount of alcohol, it will dry up significantly compared to the water.
How does it work?
This test is based on the principle that alcohol has a much lower boiling (78 C) point compared to water (100 C).
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