BIO RAD SmartSpec 3000 Instruction Manual page 29

• Press > to continue the assay, and the screen will display
Ready to read absorbance
<=Exit Assay
• SmartSpec 3000 is now ready to collect absorbance data.
b. If you do not know the molecular weight.
Enter oligo composition:
#A:___#C:___#G:___#T:___
• 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 3000 will calculate the
molecular weight and display it along with the molar extinction coefficient.
Mole Ext Coef=xxxxxxx
NW=xxxxx
• Press the right arrow key to continue the assay. SmartSpec 3000 is now ready to
collect absorbance measurements and to convert those to concentrations.
Ready to read absorbance
<=Exit Assay
iii. If you do not know the molar extinction coefficient or the mass/absorbance con-
version factor. SmartSpec 3000 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.
Select a method to find
mol ext coef:Length
• Press Select to scroll through the other options.
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
• Press Enter when your preference is displayed.
a. Length
Enter oligo length: ___
>=Options
>=Continue
>=Options
26