Bio-Rad SmartSpec Plus Spectrophotometer - Manual (Page 36)

• In order to see the information about the standard curve, press Select to toggle
from No to Yes and press Enter.
r2 refers to the square of the correlation coefficient and is a value between 0 and
1, with 1 representing a perfectly straight line (see discussion above). The general
equation of the curve fit is presented in the top right part of the display
Concentration = Absorbance*Slope + Intercept
• Press 0 to see the slope. Return to the assay by pressing the right arrow key
or go back to the previous screen by pressing the left arrow key.
If the slope or intercept has a value greater than 9999 or less than 0.0001, it will be
shown in exponential notation. In all cases with SmartSpec Plus, e represents the
base 10, not the base of the natural logarithm. For example, 100,000 would be
represented as 1.000
ε 05 and 0.00001 would be represented as 1.000 e-05.
• Press 0 to see the intercept. Return to the assay by pressing the right arrow key
or go back to the previous screen by pressing the left arrow key.
• Press 0 to see the name of the standard curve and the date that it was created.
Return to the assay by pressing the right arrow key or go back to the previous
screen by pressing the left arrow key.
• Press the right arrow key to return to the assay. SmartSpec Plus is now ready
to collect absorbance data and to covert the absorbances into concentrations
using the standard curve recalled from memory.
B. If you choose Yes, to construct a Standard Curve. The first step in construction of
a standard curve is to blank SmartSpec Plus. The instrument will prompt for the
number of blank replicates. You may have as many as 9 blank replicates, or as few as 1.
• Use the number keys to input the number of blank replicates and press Enter.
SmartSpec Plus will now direct you to put the blanks into the instrument, one after
the other.
33
Enter number of blank
replicates (1–9): ___
Insert Blank #1/3 and
Press Read Blank
Intercept (I)=xxx.xx
ε xx
<=Back 0=More >=Continue
Name: _________ 11/25/98
<=Back >=Continue
Ready to read absorbance
<=Exit Assay >=Options
r2=x.xxx CONC=ABS*M +I
0=Show more >=Continue
Slope (M) = xx.xx exx
<=Back 0=More >=Continue