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Topic: Classical Analysis for UV-Vis spec  (Read 4808 times)

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Offline ixi

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Classical Analysis for UV-Vis spec
« on: April 05, 2008, 01:57:15 PM »
This is for lab.

We had to analyze our data using the classical analysis and the multivariate analysis.

For the classical analysis, i need 4 Beer's plots
I plotted the graphs, but i want to know how to I find out with the lambda max is?

thanks

Offline ARGOS++

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Re: Classical Analysis for UV-Vis spec
« Reply #1 on: April 05, 2008, 04:30:40 PM »
Dear ixi;

I think you mean “where” the Lambdamax is? (-if I understand correct).

There are mainly two procedures to determine the Lambdamax:  A quite insecure and a much more adequate Method.

For the insecure method you can do an intensive search if somebody has already done something similar to yours and has published a numerical value!
But if you succeed that’s very insecure anyway, because ε and Lambdamax is quite dependent on the whole measuring environment!

The more secure way will be if you “scan” for the Lambdamax a Spectrum in the interesting wavelength range, or do a manual simulation of that by make several readings on increasing wavelength.
Big Advantage: As long as you keep your later method (Solvent mixture, pH, etc.) really constant, then your values fit precisely your later Concentration determination.

To inform you about most such dependencies you may visit the page:  "Corrected Beer's Law
The later “Fit” for the Calibration you can do inside of Excel, and also validate your Calibration too.

Hope I have been of some help to you.


Good Luck!
                    ARGOS++


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