Many references suggest that the formation of AgNPs is characterized by a single peak at lambda 380-420 nm. Additionally, are there any guidelines regarding the timing of characterization? I've come across 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.
I would greatly appreciate any insights or advice on these questions. Thank you in advance for your help.
Best regards,
Hey there Michelle Darmawan,
When it comes to detecting the presence of silver nanoparticles (AgNPs), the appearance of a peak in the UV-Vis spectrum around 380-420 nm is often cited as an indicator. However, the tolerance limit for the lowest wavelength peak, even if it shows a blue shift, can vary depending on the specific synthesis method and the characteristics of the nanoparticles. Generally, a blue shift in the peak could still suggest the presence of AgNPs, but the exact limit would require careful experimentation and validation.
Regarding the timing of characterization, it's commonly recommended to conduct UV-Vis analysis around 24 hours after the synthesis of AgNPs. This timeframe allows for stabilization and aggregation of nanoparticles, ensuring a more accurate representation of their optical properties. However, this timing can also depend on factors such as the synthesis protocol and the intended application of the nanoparticles.
In summary, while a single peak around 380-420 nm is often associated with AgNP formation, the tolerance limit for the lowest wavelength peak may vary. Additionally, conducting UV-Vis characterization approximately 24 hours after synthesis is a common practice to ensure reliable results. As always, it's essential to consider specific experimental conditions and consult relevant literature for further guidance.
Hope this helps! Let me know if you Michelle Darmawan need more info. Cheers!
Thank you very much for the explanation, Sir Kaushik Shandilya .
I optimized the temperature and reaction time of the synthesis using a water bath, ranging from 40-90oC for durations between 10-50 minutes. I monitored the absorbance at wavelengths between 200 to 800 nm, with a reading interval of 50 nm.
However, I encountered a challenge with the absorbance of the synthesis solution, as it was too high (exceeding 2.5 and couldn't be read). To address this, I diluted the solution at a ratio of 1:20 and found the highest absorbance at a wavelength of 300 nm.
Despite this, I conducted immediate checks after the AgNP synthesis, as the solution consistently darkened if left for 24 hours or more which was feared not being in accordance with the reaction time that was being optimized.
Do you have any suggestions regarding the procedure I have followed? Thank you very much.
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