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Spectronic 20


A Spec 20 spectrometer measures the amount of visible light absorbed by a colored solution. This can be read as Absorbance or % Transmittance.

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Setting Up the Spectrometer
Image 1
Check that the instrument is turned on. The left-hand knob should be turned clockwise. Allow 10 minutes for warming up.
Image 2
Set the wavelength to the desired value using the knob on the top.
Calibrating the Spectrometer
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With empty, closed sample compartment, turn the left-hand knob to obtain a reading of 0% T.


Use the mirror behind the needle to avoid parallax error.


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Image 5
Wipe the cuvette with a dry Kimwipe to remove drops of solution or finger prints.
Image 6
Line up the mark on the cuvette with the line on the sample compartment.

Insert cuvette filled with solvent in the sample compartment.

Close the cover.
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Turn the right-hand knob to obtain a reading of 100% T.

Using the Spectrometer
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To analyze your sample, insert sample cuvette and read the Absorbance value on the scale. Use the mirror behind the needle to avoid parallax error.

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