Bio-Rad SmartSpec Plus Spectrophotometer - Manual (Page 31)

• Press > to continue the assay, and the screen will display
• SmartSpec Plus is now ready to collect absorbance data.
b. If you do not know the molecular weight.
• Use the number keys to input the number of A’s, then press Enter to move the
cursor to the next field and enter the number of C’s. After entering the number
of T’s (or U’s for RNA oligos), press Enter. SmartSpec Plus will calculate the
molecular weight and display it along with the molar extinction coefficient.
• Press the right arrow key to continue the assay. SmartSpec Plus is now ready to
collect absorbance measurements and to convert those to concentrations.
iii. If you do not know the molar extinction coefficient or the mass/absorbance
conversion factor. SmartSpec Plus will estimate the molar extinction coefficient
and the molecular weight. You must choose which of the three methods it will use:
length, composition or sequence. The calculated molar extinction coefficient and
molecular weight will be displayed at the end. A fourth option of Do not need may
be selected if you do not want to convert the absorbance data to concentration.
Caution: Estimations based on oligo length assume an equivalent distribution of
the four bases. If your oligo composition differs significantly from this ratio, use
the composition or sequence options for more accurate estimates of molar
extinction coefficient and molecular weight.
• Press Select to scroll through the other options.
• Press Enter when your preference is displayed.
a. Length
28
Ready to read absorbance
<=Exit Assay >=Options
Mole Ext Coef=xxxxxxx
NW=xxxxx >=Continue
Select a method to find
mol ext coef: Composition
Select a method to find
mol ext coef: Sequence
Select a method to find
mol ext coef: Do not need
Enter oligo length: ___
Select a method to find
mol ext coef:Length
Enter oligo composition:
#A:___#C:___#G:___#T:___
Ready to read absorbance
<=Exit Assay >=Options