Ultra low range free chlorine measurement
An embodiment provides a method for measuring free chlorine in a solution, including: preparing a thiocarbamate-based indicator; introducing the thiocarbamate-based indicator to a solution, wherein the solution contains an amount of free chlorine and the introducing causes a change in fluorescence of the solution; and measuring the amount of free chlorine in the solution by measuring a change in intensity of the fluorescence. Other aspects are described and claimed.
1. A method for measuring free chlorine in a solution, comprising:
preparing a thiocarbamate-based indicator;
introducing the thiocarbamate-based indicator to a solution, wherein the solution contains an amount of free chlorine and the introducing causes a change in fluorescence of the solution, wherein the solution comprises a monochloramine interfering species;
titrating the solution to a pre-determined pH; and
measuring the amount of free chlorine in the solution by measuring a change in intensity of the fluorescence, wherein the method for measuring provides for an output of free chlorine based upon a fluorescence curve generated for a condition affecting the change in intensity of the fluorescence of the solution, wherein the generated fluorescent curve comprises a condition of the solution that affects absorption values, wherein the intensity of the fluorescence is correlated to a concentration of the free chlorine in the solution.
2. The method of claim 1 , wherein the thiocarbamate-based indicator comprises a methylumbelliferone derivative.
3. The method of claim 1 , wherein the thiocarbamate-based indicator comprises a coumarin based fluorophore.
4. The method of claim 1 , wherein the solution comprises a water sample.
5. The method of claim 1 , wherein the solution comprises monochloramine.
6. The method of claim 1 , wherein the solution comprises hypochlorous acid.
7. The method of claim 1 , wherein the amount of free chlorine comprises an amount less than 7 ppm.
8. The method of claim 1 , wherein the measuring further comprises titrating a pH of the solution to substantially a pH of 8.
9. The method of claim 1 , wherein the measuring comprises measuring fluorometry with a hand-held device.
10. A measurement device for measuring free chlorine in a solution, comprising:
a processor; and
a memory storing instructions executable by the processor to:
prepare a thiocarbamate-based indicator;
introduce the thiocarbamate-based indicator to a solution, wherein the solution contains an amount of free chlorine and the introducing causes a change in fluorescence of the solution, wherein the solution comprises a monochloramine interfering species;
titrate the solution to a pre-determined pH; and
measure the amount of free chlorine in the solution by measuring a change in intensity of the fluorescence, wherein the measurement device provides for an output of free chlorine based upon a fluorescence curve generated for a condition affecting the change in intensity of the fluorescence of the solution, wherein the generated fluorescent curve comprises a condition of the solution that affects absorption values, wherein the intensity of the fluorescence is correlated to a concentration of the free chlorine in the solution.
11. The device of claim 10 , wherein the thiocarbamate-based indicator comprises a methylumbelliferone derivative.
12. The device of claim 10 , wherein the thiocarbamate-based indicator comprises a coumarin based fluorophore.
13. The device of claim 10 , wherein the solution comprises a water sample.
14. The device of claim 10 , wherein the solution comprises hypochlorous acid.
15. The device of claim 10 , wherein the amount of free chlorine comprises an amount less than 7 ppm.
16. The device of claim 10 , wherein the measuring further comprises titrating a pH of the solution to substantially a pH of 8.
17. A method for measuring free chlorine in a solution, comprising:
preparing a thiocarbamate-based indicator, wherein the thiocarbamate-based indicator comprises a methylumbelliferone derivative comprising a coumarin based fluorophore;
introducing the thiocarbamate-based indicator to a water sample, wherein the solution contains an amount of free chlorine and the introducing causes a change in fluorescence of the solution, wherein the solution comprises a monochloramine interfering species;
titrating the solution to a pre-determined pH; and
measuring the amount of free chlorine in the solution by measuring a change in intensity of the fluorescence, wherein the fluorescence intensity is correlated to a concentration of the free chlorine in the solution, wherein the method of measuring provides for an output of free chlorine based upon a fluorescence curve generated for a condition affecting the change in intensity of the fluorescence of the solution, wherein the generated fluorescent curve comprises a condition of the solution that affects absorption values, wherein the intensity of the fluorescence is correlated to a concentration of the free chlorine in the solution.
18. The device of claim 10 , wherein the measure of the amount of free chlorine in the solution is in the range of about 2 to about 20 parts per billion (ppb).