- Turn on the computer. Open the StellarNet software by double clicking on the desktop icon StellarPro
to open the application. - In the side navigation bar, select Scope icon
and you should see a screen that looks like:
- Click on the Scope tab in the Graph window. This will show you the number of counts (photons) the detector receives. You should see a spectrum of counts versus wavelength.
- Remove the cuvette holder cap. Place your most concentrated standard cuvette into the cuvette holder and replace the cuvette holder cap.
- Set the integration time so that your spectrum is not saturated but as close to 65,000 counts as possible. Enter the desired time in the integration time input box, then click on the “Int Time (ms)” button next to the input textbox to apply the entered time. The goal is to maximize your signal in SCOPE mode. You want to adjust your integration time until the spectrum fills most of the SCOPE graph (65,000) without saturating. This is also the point at which you should adjust the number of scans to average (more scans averaged will increase accuracy, but will take more time for each reading). You can also add smoothing controls at this time in the Device Settings block. A smooth value set to 3 and averaging set to 5 often gives nice results.
- In the first picture below, the spectrum is correctly optimized to be just below the saturation limit (65,536 counts).
- In the second picture below, the spectrum have a flat line on the top, indicating the need to reduce the integration time.
- In the first picture below, the spectrum is correctly optimized to be just below the saturation limit (65,536 counts).
- Take a dark reference. Press the red button on the back of the light source (orange box). The button will be pressed in if the LED light is on. If the button is not pressed in then the LED light is off. After several minutes, the baseline will settle (A).
7. Once the baseline has settled, left click on the dark light bulb icon
or 
in the toolbar at the top right of the screen. The baseline will drop to zero (B).
Taking Fluorescence Measurements
- Turn LED light on. Press the red button on the back of the light source (orange box). The button will be pressed in if the LED light is on. If the button is not pressed in then the LED light is off.
- Remove the cuvette holder cap. Place the most concentrated standard cuvette in the cuvette holder and replace the cuvette holder cap.
- Remain in Scope mode. The instrument will now display the photon count (intensity) versus wavelength in real time.
- To find a peak, use the mouse to left click on either of the following icons in the Acquire tab of the toolbar:
- The left arrow will find a peak to the left of the vertical line in the spectra. The right arrow will find a peak to the right of the vertical line in the spectra.
- You can also right click directly onto the spectrum to find the photon count of a specific wavelength. To find the specific wavelength your cursor is at, look to the top right of the annotation for the spectrum. Wave gives the specific wavelength and Value gives the photon count for that particular point in the spectrum.
