- minimum volume: 5 mL
- use green-capped test tubes (larger diameter)
- use a blank containing your media
- ok to leave on all day, but do turn it off when done
- bulbs are cheap (UV bulbs are generally the expensive ones)
- Turn on by turning leftmost dial clockwise
- Allow the spectrophotometer to warm up for at least 15
minutes to stabilize.
- Set filter to 600 nm (or whatever)
- Zero transmittance with left knob
- Put in blank & cover with black cap
- set transmittance to 100
- absorbance for the blank should now be 0
- Measure absorbance for your sample
- Keep tube orientation the same each time you measure in case of any unevenness.