USING THE SPEC-20 FOR GLUCOSE ASSAY

1. Plug-in the Spec-20 and turn it on using the left front knob. Let it warm-up for 15 minutes.

2. Set the wave length to 500 nanometers by using the knob on the top and the associated dial. Check this EVERY time.

3. After warm-up, use the left front knob to set the needle to zero transmittance.

4. Adjust for blank.
   • Open the trap-door on top left and insert a cuvette with blank liquid (usually the analysis reagent).
   • Use the right front knob and adjust the absorbance to zero. Remove the blank, close the trap door, and re-check the zero reading. Re-adjust if necessary.
   • Repeat this adjustment sequence until two sequential readings for the blank show the absorbance stabilized at 100%. This may require several iterations.

5. Read the sample (or glucose standard) by inserting the sample cuvette and recording absorbance.

6. Repeat the sequence of adjusting the blank and reading a sample until all samples are complete. (Note: these old machines have a tendency to drift, so it is important to check and adjust the blank to zero absorbance after each sample measurement.)