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Why is it important that all absorbance readings for the calibration curve be measured at the...

Why is it important that all absorbance readings for the calibration curve be measured at the same wavelength?

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Expert Solution

All elements / molecules have unique molar absorbances, that is, 1 mole of each molecule will absorb a specific amount of a (or several) specific wavelengths of light.

Since it is the atoms/molecules that absorb the wavelenghts of light, the more there are in a sample the more of the particular wavelenghts will be absorbed, so as the concentration of the sample increases the absorbance will increase.

The calibration involes running several standards of known concentration through the spectrophotometer at a same wavelength. Because at each concentration you should get a different absorbance for same wavelength. For the calibration to work you must end up with a curve.

The absorbance is plotted against the concentration to give the calibration curve. This is not always linear, but it can be.
At any point on this curve you can work out a concentrtion of a sample from the abs. and vice versa.

queen_honey_blossom answered 2 years ago
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