1. Plug in and turn on the Spec 20. It must warm up for 30 minutes before use.
   
   
2. Set the instrument to the proper wavelength by turning the knob located on the right hand surface of the spectrophotometer. The wavelength setting can be seen through the window next to the knob.
   
   
3. Obtain a properly cleaned cuvette and fill it about 3/4 full of the reference solution (usually water).
   
   
4. With no cuvette in the sample holder, close the cover and rotate the zero light control knob(left front knob) to display a reading of 0.0% transmittance. Provided that the instrument is not turned off and this knob is not moved, no other adjustments to this control are needed.
   
   
5. Place the reference solution cuvette in the sample holder, close the cover, and rotate the light control knob (front right knob) to display a reading of 100.0% transmittance. This procedure must be repeated every time measurements are taken at a new wavelength or if several measurements are made at the same wavelength.

1. Calibrate the instrument (see above instructions) at the wavelength you wish to measure. You will use the solvent of your sample solution as your reference (this will usually be water).
   
   
2. Fill a properly cleaned cuvette 3/4 full of you sample solution.
   
   
3. Place your sample cuvette in the sample holder and close the cover.
   
   
4. Read either the absrbance or percent transmittance as needed.
   
   
   

Spec 20 Menu