Calibration
Calibration of the Digital C-FLUOR
The Digital C-FLUOR Probe is factory calibrated and the calibration values are stored in memory. The probe can be re-calibrated by users via software if site-specific calibrations are desired for increased accuracy. New calibration values will be stored into memory without overwriting or erasing factory calibration values. This allows users to restore factory calibration values if desired. Note: Restoring factory calibration values will erase all customer calibration values.
To calibrate Digital C-FLUOR you’ll need the following materials:
Digital C-FLUOR
PC with Digital C-FLUOR Software
RS-232 Programming Cable P/N 2120-160
12-Volt Power Supply P/N 7000-941
Blank solution (Typically Deionized Water)
Standard solution of known concentration
Blackened or dark 500 ml beaker/container
Use of the Digital C-FLUOR Software for Calibration
See section 2.4 in User Manual: 998-2131.pdf (turnerdesigns.com) on Functional Test for Digital C-FLUOR with connector on how to connect to your computer.
Click the “Calibration” tab
Enter the known concentration of your Standard Solution in the Concentration Value box. Note: Only values greater than 1 are valid.
Fill your 500 ml beaker with blank solution.
Submerge the probe’s optical head no more than an inch below the surface of the blank solution. See Appendix B for recommended lab practices.
Click the “Calibrate C-FLUOR” button, then click “OK”.
Wait for the progress bar to complete.
When prompted to insert C-FLUOR into Calibration Solution, remove the probe from the blank solution.
Empty the blank solution from the beaker and wipe the beaker dry.
Fill your 500 ml beaker with standard solution.
Submerge the probes optical head no more than an inch below the surface of the standard solution. See Appendix B for recommended lab practices.
Click “OK”.
Wait for the progress bar to complete.
Click “Yes” to save the new calibration.
Click “Get Datapoint” to read the standard solution with the newly calibrated probe; you should see the Concentration Value you entered displayed in the “Datapoint Value” box confirming the calibration was saved.
Calibration of the Analog C-FLUOR
The Analog C-FLUOR Probe is factory calibrated and the calibration values are stored on a certificate. The certificate also contains an equation that can be used with the calibration values to convert C-FLUOR’s voltage signal to concentration estimates for the specified fluorophore of interest.
For increased accuracy when estimating fluorophore concentrations you can create user-defined calibrations via voltage signal offsets with ultrapure water and a voltage signal proportional to the sample fluorophore of interest. The section below will explain how to make these offsets.
Example of C-FLUOR certificate below:
To calibrate Analog C-FLUOR you’ll need the following materials:
Analog C-FLUOR
Blank solution (Typically Deionized Water)
Standard solution of known concentration
Blackened or dark 500 ml beaker/container
Multimeter or a datalogger that accepts analog outputs
First, Determine your Blank Offset for Analog C-FLUOR
C-FLUOR’s Factory Offset is measured using ultra-pure water. When working in an environment where background fluorescence values are greater than the factory measured Offset, you may want to consider using an Offset that is more suited for your water type. To determine an Offset for your water type:
Collect a sample of water that represents the water type you will be measuring.
Remove the fluorophore of interest from that water sample. For example, for in vivo chlorophyll you would filter the water sample through a glass microfiber filter or similar filter to remove all algal cells from the sample.
Once the fluorophore of interest is removed from the water sample, measure that sample using the C-FLUOR and record the voltage response.
Your Offset will be equal to that voltage response so all voltage measurements for that water type should have this Offset subtracted.
Second, Determine your Known Concentration Offset for Analog C-FLUOR
The Calibration Coefficient stated on the calibration certificate is a correlation between a standard of known concentration and the Offset-corrected response for that standard. To create your own calibration coefficient:
Determine an Offset for your water type - see above section
Obtain a standard that:
Has a known concentration.
Falls within the measuring range of the C-FLUOR.
Measure the response of that standard.
Subtract the Offset from that measured response.
Divide the concentration of the standard by its Offset-corrected response.
Your result is a calibration coefficient that can be used to convert Offset-corrected voltages to direct concentrations.
C-FLUOR Probes output a 0-5 Volt analog signal proportional to the fluorescence detected from the fluorophore of interest.
Use the wiring diagram below to connect the C-FLUOR to a power supply and a multi-meter or datalogger that will read voltages from the probe. Submerge the optical head, or entire probe, into the water sample; the voltage displayed indicates the relative amount of fluorophore in your sample. Correct the measured voltage by subtracting the Offset and then multiply by the determined Calibration Coefficient to calculate fluorophore concentration. If reading samples in a container, see our C-FLUOR FAQ for recommended measurement practices.
C-FLUOR Probes can be integrated into any third-party system that can supply 3 – 15 VDC and accepting a 0-5 Volt analog signal.
C-Fluor Wiring Diagram for Analog C-FLUORs with Connector pins to pigtail cables:
Analog C-FLUOR Functional Test with Wiring Diagrams and Power Supply:
