We have done a UV-Vis characterization for the silver colloidal solution by using UV-Vis double beam spectrophotometer (Perkin-Elmer, Lambda 25). The result is as shown in the attached file and the curve seems to be good until the UV region at which the curve has noise in the peak especially when the curve has high intensity (Y-axises). Otherwise, other samples of the silver colloidal solutions that have less intensity appear with good results in the UV region. So why is this happening?
Thanks
Larger Integration time and averaging may help.
But here is something which you might consider
When A = 2, transmitted light is only 1%. Measuring 1% of the light by the instrument is asking too much from the components present in the instrument. So any measurement close to 2 or higher is always prone to large errors. It is always better not to measure it in that range.
Larger Integration time and averaging may help.
But here is something which you might consider
When A = 2, transmitted light is only 1%. Measuring 1% of the light by the instrument is asking too much from the components present in the instrument. So any measurement close to 2 or higher is always prone to large errors. It is always better not to measure it in that range.
Please revisit Beer-Lamberts Law.
The concentration of your solution is simply to high. If you want to have good spectra in the sense that you want to be able to calculate concentrations using an extinction coefficient you want to have A < 1. Usually with A > 1 linearity of the law is lost and anything can happen.
Of course as stated by V. N. Ravi Kishore V. the little amount of transmitted light (which in your case is caused by multiple scattering and absorption because of the high particle density) causes an high error.
Just dilute your sample for the measurement by a factor of 5 to 10 and you will have nice spectra.
Hi there,
Usually the problem regarding peaks in UV-Vis spectrophotometer can be solved by reducing (or lowering) the concentration of the solution. Try to prepare the sample in concentration X10-5Mor X10-6M.
There is an in depth study of the systematic errors generated by multiple scattering from the good old days. As far as I remember it is due to monochrome light is overlaid by light of different wavelength.
like Andreas Henkel and other have written, your Absorbance is too high. With lower concentration you can solve this problem. But if you need a high concentration, you can also solve the problem by a shorter path lengths ( shorter cuvettes )
Thank you so much our Dear Titus Sobisch and Nicolai Krekiehn for your explanation.
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