After nanoparticle synthesis using plant source, we need to take the absorbance data to see the high peak. My question is -
Do I need the blank to get the absorbance data or I can get the absorbance data by keeping the nanoparticle solution in different wavelength?
Dear friend Md. Shoebul Islam
According to the Beer-Lambert law, the absorbance of a solution is proportional to the concentration of the absorbing species in the solution. The blank is used to zero the spectrophotometer before measuring the absorbance of the standard and unknown solutions. Every standard curve is generated using a blank. The blank is some appropriate solution that is assumed to have an absorbance value of zero (8.5: Spectroscopic Characterization of Nanoparticles....). Therefore, it is recommended to use a blank when measuring absorbance data.
I hope this helps! Let me know if you have any other questions.
Source:
(1) 1.2: Beer’s Law - Chemistry LibreTexts. https://chem.libretexts.org/Bookshelves/Analytical_Chemistry/Molecular_and_Atomic_Spectroscopy_%28Wenzel%29/1%3A_General_Background_on_Molecular_Spectroscopy/1.2%3A_Beers_Law.
(2) What is negative absorbance and why am I getting it?. https://www.researchgate.net/post/What_is_negative_absorbance_and_why_am_I_getting_it.
(3) 8.5: Spectroscopic Characterization of Nanoparticles. https://chem.libretexts.org/Bookshelves/Analytical_Chemistry/Physical_Methods_in_Chemistry_and_Nano_Science_%28Barron%29/08%3A_Structure_at_the_Nano_Scale/8.05%3A_Spectroscopic_Characterization_of_Nanoparticles.
(4) Solubility of Nanoparticles - Kansas State University. https://www.phys.ksu.edu/reu2016/hbuckner/.
Using a blank in Absorbance spectroscopy is normally used to take account of factors such as reflection from the surface of a cuvette, which often add a broadband baseline to the absorbance measurement.
If you can't measure a blank (a cuvette with just the solvent!), any baseline can be estimated from regions of the spectrum where there is no solute absorbance.
A concentration dependence of the solute should (for each wavelength) result in a straight line of slope Extinction co-efficient *pathlength and an intercept on the y axis of the baseline
Thank you very much for your nice explanation Dear Kaushik Shandilya
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