Hoefer SP-2001 Vision Life Spectrophotometer - Manual (Page 44)

Version 1.0
Page 44
4: Lowry
The procedure is as follows:
Step 1
Press 4 to select Lowry method.
Step 2
Wavelength for this stored method is pre-set to 750 nm.
Step 3
Enter the number of standard concentration points (1-9) to be
used in the curve using the keypad numbers or left and right
arrows.
Press the down arrow.
Step 4
Units: The user can enter a text string up to 8 characters long.
To access a list of pre-defined units press the Options key ::;
and then use the left/right arrows (μg/ml, μg/μl, pmol/μl, mg/dl,
mmol/l, μmol/l, g/l, mg/l, μg/l, U/l, %, ppm, ppb, conc or none).
These units can also be edited once OK is pressed.
This screen also allows the number of displayed decimal points
(DP) to be selected, from 0 to 2 Note that the result will always
be fixed to 5 significant figures regardless of how many decimal
points are selected (so 98768.2 will display as 98768 even with 1
decimal point selected).
Press OK
to store the chosen parameters or Cancel .
Step 5
Enter the type of curve fit. Options are straight line regression,
zero regression (forces the straight line through the origin),
interpolated or cubic spline.
Press the down arrow.
Step 6
Select the calibration mode, either standards (measure prepared
standards) or manual (keypad data entry)
Step 7 (if standards selected)
Select the number of replicates using the left and right arrows.
This determines the number of standards to be measured and
averaged at each standard concentration point. Can be OFF (1),
2 or 3.
Step 8
Press Next
to enter the Standards screen
OR
Press Cancel
to cancel selections and return to the Protein
folder.
Standards Screen
Step 9
Enter the concentration values by using the keypad numbers and
the up and down arrows to move between the different standard
boxes. Range 0.001 to 9999. C button backspaces and clears
the last digit entered.
Step 10
Press Next
to enter the Calibration screen. If there are
duplicate or non-monotonic (increasing) entries the unit will beep
and highlight the incorrect entry.
OR
Press Back
to return to the Parameter screen