NanoPhotometer
®
NP80/N60/N50/C40
User Guide Version 3.1
52
this is generally indicative of contamination with guanidinium thiocyanate, a reagent commonly
used in RNA purification and which absorbs over the 230-260 nm range. If a ratio is detected
out of the acceptable range an alert icon
is shown in the results/table area. A click on the
alert icon shows additional information. The ranges for acceptable ratio values can be defined in
preferences.
The ratios are calculated with or without background correction according to if the background
correction is activated during the measurements or not as follows:
Without background correction:
260/280 ratio =
A
260
A
280
260/230 ratio =
A
260
A
230
With background correction:
260/280 ratio =
A
260
- A
BKG
A
280
- A
BKG
260/230 ratio =
A
260
- A
BKG
A
230
- A
BKG
