1. If I air dry the sample overnight, how should I prepare it for UV-Vis, FTIR, DLS, and SEM/TEM characterization?
2. Do I need to add a buffer to maintain sample solubility? Should the characterization be conducted immediately afterward?
3. In UV-Vis spectrophotometry, is it acceptable to check the colloidal solution before centrifugation and washing with deionized water? If I dilute the sample with a certain ratio because the crude AgNP colloidal solution is not within the range of 0.2-3, is that acceptable?
I would greatly appreciate any insights or advice on these questions. Thank you in advance for your help.
Best regards,
I dont think that it is a good approach to purify AgNPs with deonised water etc. most probably you obverse aggregation.
If you dry your suspension then UV-Vis, DLS wont provide you real size.
I recommend to use initial samples for UV-Vis, DLS
Thank you for the response Dmitriy Berillo I attempted to directly examine the AgNP colloidal solution produced without centrifugation and washing using a DLS instrument. However, the results remained unsatisfactory (Pi 1.190 and z average 555 nm with a mean zeta potential of -28.9 mV). Upon reviewing various papers and forums, it was recommended to perform centrifugation and washing prior to characterization. However, there was no detail explanation about that. Could you please suggest an appropriate method or reference procedure to improve the characterization results? Currently, I am planning to optimize the concentration of plant extract, AgNO3, and reaction time.
Michelle Darmawan
It is necessary to understand the solution to the problem using methods
1.UV-Vis. You determine the amount of absorption from the interaction of plasmons of nanoparticles in the visible region and prove, by comparison with other studies, that you have nanoparticles. If you reduced with hydrazine or borohydride, then you don’t have to dry the dispersion. If you restore with leaf extract, then there may be the presence of coloring substances that can change the plasmon band.
2.FTIR. You determine the presence of functional groups after the reaction. It is necessary to work with dispersion.
3.DLS. It is necessary to work only with a stable dispersion without agglomerates.
4.SEM/TEM. Prepare the dry film so that it is sparse and individual nanoparticles are visible. The sample will be placed in a vacuum and therefore must be dried under vacuum in air. Do not heat.
Thank you very much for the thorough explanation of each instrument, Sir Yuri Mirgorod . Would you mind if I ask a few more questions, particularly regarding UV-Vis testing?
1. You mentioned that using plant extracts as reducing agents may introduce coloring substances that could alter the plasmon band. How can I prevent this?
2. Is there a tolerance limit for the presence of the lowest wavelength peak (a blue shift) that still indicates the presence of AgNP? Many references suggest that the formation of AgNPs is characterized by a single peak at lambda 380-420 nm.
3. Are there any guidelines regarding when I should conduct the characterization? I've encountered a paper stating that UV-Vis characterization is typically conducted 24 hours after AgNP synthesis to ensure the presence of a peak around 400 nm.
4. For other tests like FTIR, DLS, SEM/TEM, could you recommend readings outlining the complete procedure and any applicable dilution rules?
Thank you once again for your assistance.
Michelle Darmawan For Uv-Vis, make sure to prepare a blank/control sample from the plant extract. Zeroed the Uv-Vis before reading the sample using the control.
- Badges
- Science topic
- Similar topics
- Chemistry