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Turning on the Olis DSM CD
1
Turn on the lamp cooling box.
2
Turn on the nitrogen flow to the lamp and
monochromator to at least 6 L per min.
Higher flow rates
in the monochromator should be used if data are to be
taken before 200 nm.
3
Turn on the power supply for the lamp.
4
Press and hold the ignite button until lamp ignites.
Ensure
that the current to the lamp does not exceed 7.5 Amps.
5
Turn on the main power switch at the power strip.
4
Turn on the computer and open GlobalWorks program.
5
Select the
Data Collection
tab and double click on
Conv CD
.
6
The spectrophotometer will initialize and calibrate.
Changing CD units of data collection
‰
One may choose from several units of data collection in
the
Parameters
tab under
CD Units
.
Milliabsorbance
: Reports data as the difference in
absorbance of left circularly polarized light and right
polarized light. (
Abs
Left
-Abs
Right
)
Molar Extinction
: Reports the difference in extinction
coefficients for left and right polarized light. (
(
Left
-
(
Right
)
Millidegrees
: Reports ellipticity in units of millidegrees..
Molar Ellipticity
: Reports molar ellipticity in units of
deg cm
2
/dmol. The user must provide the program with protein
concentration (g/L), cell pathlength (cm), and mean residue
weight (g/mol).
Taking a wavelength scan
1
Open the
Operational Modes
tab and set the
Data
Collection Mode
to
Scan
.
2
Ensure that the proper
Data Reduction Mode
is selected
(i.e.,
Circular Dichroism
).
3
Go to
Live Display
tab.
4
Change
Wavelength Scan Range
to desired range.
5
Click on
Live Mode
button and adjust
PMT HV
value to
give an acceptable signal (If you have photon counting
you cannot change
PMT HV
).
6
Enter the desired number of increments to be collected
and the integration time for each point.
7
Click on the
Collect Data
button to begin scan.
Taking repeated scans
1
Under
Repeated Scans
tab, change
Number of Scans
to the desired number. Scans can be made automatically
as a function of time, or manually. In the
Auto
mode, the
time selected is the total time to complete all scans. In the
Manual
mode, scans are started by pressing the spacebar.
2
Select
Manual
or
Auto
as the
Scan Mode
on this page.
3
Ensure that
Time Units
are correct. These can be
changed in the
Operational Modes
tab.
‰
All repeated scan data will be saved as a single, 3-D data set.
‰
Selecting
Average Scans
results in an output of a single,
averaged scan.
Taking repeated scans as a function
of a temperature script
1
In the
Repeated Scans
tab, select the desired temperature
script by entering or browsing to the correct file.
2
To edit a script file, click on
Edit Script
and change the
number of scans, temperatures and integration times.
3
Check that the temperature controller is set to
On
in the
Temperature Control
tab.
4
In the Repeated Scans tab, set
Repeat Scans as a
function of
to
Temperature Script
.
The
Number of
Scans
value should change to be equal to the number of
scans in the temperature script.
5
Select appropriate data collection parameters in the
Live
Display
and
Operational Modes
tabs.
6
Click on Collect Data to begin Scans.
Taking an assay
1
Under the
Operational Modes
tab, set the
Collection
Mode
to
Assay
.
2
Enter
Total Assay Time
in the
Live Display
tab.
3
Set
Current Wavelength
to the desired assay wavelength.
4
Enter
Number of Points to Collect
and
Integration
Time
per data point.
5
To subtract an offset from the data, click on the
Zero
Instrument
button.
6
To begin the assay, click on the
Collect Data
button and
press spacebar when prompted.
Collecting repeated scans as a
function of a titrator script
1
In the Repeated Scans tab, set
Repeat Scans as a
function of
to
Titrator Script
.
2
Follow instructions for calibration.
3
Load solution into titrator using the
Titrator Control
Panel
to move syringes.
4
To edit a script file, click on
Edit Script
.
5
Select appropriate data collection parameters in the
Live
Display
and
Operational Modes
tabs.
6
Click on
Collect Data
to begin Scans.
Quick Reference How-To Guide
for the Olis DSM CD Models
Summary of Contents for DSM CD
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