The Department of Biological Sciences at the University of Alberta brings you this video tutorial specifically relevant to your student laboratory courses, specifically microbiology. If you're a student at any school of biology, this information will be helpful for learning how to use the Spectronic 21 visible spectrometer in the lab.
Part A: The spectrometer is turned on and left to warm up.
Part B: The absorbance is set to 550 nm by the dial.
Part C: The spectrometer is blanked. The blank for this experiment is water. The liquid used may change depending on the experimental set-up. The water is put into a cuvette (don't touch the bottom with your fingers) and the cuvette is put into the spectrometer. The line on the cuvette should match up with the tick on the outside of the cuvette holder. If the cuvette doesn't have a line, draw one on with a sharpie (careful - it will come off with ethanol). Now the Absorbance (bottom scale) reading is set to 0 with the blank inside the spectrometer.
Part D: The cuvette is removed and cleaned and the sample is put in the cuvette; the cuvette is put into the spectrometer (make sure the line on the cuvette matches the tick mark). The lid is closed.
Part E : The absorbance is read (0.38 on the bottom scale). Note: because of the position of the camera parallax caused the reading to look like 0.4. Make sure that when you do your readings you look at the needle directly and not from the sides.
Important: the cuvette must be washed between each use.