Purification Method of Silver Nanoparticles (AgNPs) and its Identification Using UV-Vis Spectrophotometer

The development of nanotechnology applications is rapidly growing in many sectors. One
of them is silver nanoparticles (AgNPs) which are metal nanoparticles that play an important role,
especially in nanomedicine. The most effective method of purifying to obtain stable AgNPs is very
important to study. Experiments on the separation of AgNPs have been carried out using the size
exclusion chromatography and centrifugation methods to see the effectiveness of refining the two
methods. This experiment begins with the synthesis of AgNPs using the chemical reduction method.
Then, the synthesized AgNPs were purified by Size Exclusion Chromatography (SEC) and
centrifugation method then analyzed using UV-Vis spectrophotometer to determine the maximum
peaks before and after purification. The experimental results were obtained that centrifugation
methods and SEC having the same effectiveness in refining AgNPs. The centrifugation method at
various speed (0, 3000, 6000, 9000, 12000 and 15000 rpm) gave wavelength results 403, 404, 404,
405, 404, and 404 nm. The SEC method using Sephadex-25 column showed the 4th to 8th fractions
gave the maximum wavelength 404, 404, 404, 405, and 404 nm, respectively. The maximum
wavelength of both methods showed the surface plasmon resonance characteristic of AgNPs.
However, centrifugation at 3000 rpm has better homogeneity than SEC method.