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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

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