Bio-Rad SmartSpec Plus Spectrophotometer - Manual (Page 16)

4.5 Keypad Descriptions
Print SmartSpec Plus will print data on the current sample,
a user-selectable range of samples or all samples in the
current assay.
Abs SmartSpec Plus will automatically display the
absorbance reading of the current sample and the
wavelength being read. If more than one wavelength
is being read, press Abs to toggle among the different
wavelengths. If you are reading one of a replicate
group, you can choose to see the absorbance of the
current replicate or you can see the mean and standard
deviation of all members of the replicate group by first
pressing Abs.
Conc The Conc key is used in the DNA Oligo and RNA
Oligo assays to toggle the display of concentration
from units of µg/ml to pmoles/µl. This key has no
function for the Scan, Kinetics and
λ assays.
A260:A280 SmartSpec Plus will calculate and display the ratio of
A260 to A280. This is a method of approximating the
purity of nucleic acid preparations; pure preparations of
DNA have ratios of about 1.8 and pure RNA preparations
have a ratio of about 2.0. If you are using background
compensation (in Setup), then the ratio is calculated
after the background reading of A320 is subtracted
from the A260 and A280.
Dilution Factor The dilution factor is used as a final multiplier in
calculation of concentration from absorbance data.
The default dilution factor is 1.0 and the dilution factor
is reset to 1.0 each time that one of the Assay buttons
is pressed. The adjusted concentration will be printed
on the final report only if the dilution factor is changed
after measuring each unknown sample.
Setup SmartSpec Plus will enter the setup routine where you
can specify the pathlength, defaults for certain options,
time and date convention and time and date. You exit
Setup either by proceeding all the way through the
routine, or by pressing Cancel at any time. When you
exit the Setup routine, all changes are saved.
Assay Buttons The six assay buttons are in the second row of function
keys on the face of the SmartSpec Plus. Press one of
these to begin an assay with SmartSpec Plus. When
any assay button is pushed, SmartSpec Plus resets the
sample number to 1, and checks the memory for
unprinted data.
DNA/RNA SmartSpec Plus will automatically collect absorbance
data at 260 and 280 nm, and use those readings to
calculate nucleic acid concentration. If selected in
Setup, background will automatically be subtracted at
320 nm. The calculation of concentration depends on
the type of nucleic acid specified.
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