SILNAN-50 Recipe


Easy to make citrate capped Silver Nanoparticle Suspension


This article explains the detailed procedure to prepare a Silver Nanoparticle suspension of approx. 50 ppm (0.005% silver strength).

Materials Required

1. Silver Nitrate (AgNO3)
Silver Nitrate acts as the source of silver ions for preparing Nano Silver. Silver Nitrate is a widely used laboratory reagent and can be obtained from laboratory chemicals shop. The laboratory reagent grade of any good brand like, Sigma, Merck, Loba, SD Fine, etc should be good enough. Please read the MSDS (Material Safety Data Sheet) of Silver Nitrate on internet before handling. Do not touch Silver Nitrate with bare hands and avoid its contact with skin, eyes, inhalation or ingestion.

Trisodium Citrate
Trisodum Citrate acts as reducing and capping agent. Reducing action converts Silver Ions into Silver Particles and Capping action limits the particle size growth, keeping the silver particles in nano size.
Trisodium Citrate can be obtained from laboratory chemical shop.

Distilled Water / Deionized Water
Distilled water / Deionized water should be used because it is free from chloride ions which can interfere with silver ions. Distilled water / Deionized water can be sourced through laboratory chemical shop or elsewhere. R.O water can also be used if adding a drop of silver nitrate solution does not makes the water appear turbid.

Aluminum foil
Aluminum foil is required to cover the container to prevent light exposure.


Step 1
Take 500 ml distilled water in a glass beaker/jar. If glass is not available, then stainless-steel container can also be used.

Step 2
Weigh 36 milligrams of Silver Nitrate. To weigh this small quantity, you need a small electronic balance which can measure this small quantity. Mostly goldsmiths/silversmiths have such precision balance with them.

Step 3
Weigh 500 milligrams of Trisodium Citrate. Make a solution by dissolving 500 milligrams Trisodium Citrate in approx. 50 ml distilled water. Keep this solution separate for a later step.

Step 4
Keep the distilled water (of Step 1) covered with aluminum foil, on heating on a hot plate, gas burner, etc. Also place a thermometer in the container to note the temperature.

Step 5
Add the 36mg Silver Nitrate to the distilled water (of Step 4) and stir for its dissolution. Keep the container’s exposure to light as less as possible.

Step 6
When the hot silver nitrate solution is between 90 to 95°C, start addition of Trisodium Citrate solution (of step 3) to it in a dropwise manner using a dropper. Take about 10 minutes to add the complete quantity of Trisodium Citrate solution and add as evenly as possible with slow stirring. Try to maintain the temperature as close to 95°C as possible during the addition of Trisodium Citrate. After completion of addition maintain the solution close to 95°C for 5 minutes. After that stop heating.

Step 7
You will observe after addition of Trisodium Citrate that the solution is becoming yellowish in color. In about 10 minutes the color of solution is golden yellow. This is the point where you should start cooling the solution to room temperature. Fast cooling by keeping the vessel in a water bath or ice-water bath is advisable. Silver Nano suspension of approx. 50 ppm is now ready!!
Remember that the color of the suspension should be golden yellow or dark yellow. It should be not more than slightly brownish. If the color is more towards brown or greyish then it indicates wrong preparation.
If UV-Spectrophotometer is available, then it can be tested by running a scan for absorbance from 300 to 700 nm. There should be a maxima peak in between 410 to 430 nm indicating formation of Silver Nanoparticles.

Step 8
Once the solution is at room temperature or even warm, transfer the solution to a non-transparent plastic bottle and keep it in refrigerator (not the freezer).

Always store in refrigerator for a shelf life of approx. 3 months.

Note: The above recipe is described for making 500 ml Silver Nano Suspension but one may increase the scale of the batch keeping everything in the same proportion as described then a larger batch can be made following same procedure.

Warning: This article is just an experimental procedure to be performed taking all due care for protection and safety and only by those who can conduct such experiments. The Silver Nano suspension made through this procedure is just an experimental and research stuff and is not to be assumed as an approved medicine, cure or prevention of any disease and neither as a health or dietary supplement. Any kind of its use should be done at one’s own discretion, responsibility & risk. The author of this article does not claim any sort of benefit of any kind from the article/material generated through the given procedure. The described procedure is author’s own modification of Turkevich method of synthesis of Silver Nanoparticles. Even if the author has described some use of this material on himself, it should not be taken as a suggestion, advice or inspiration to do so.

Author: Achal Agrawal, India

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