US 12,422,423 B2
Method of measuring benzimidazole-based compounds in water
Kishor Padmakar Dhake, Nashik (IN); Anup Pandurang Thakur, Jalgaon (IN); and James Joseph Michels, Naperville, IL (US)
Assigned to Ecolab USA Inc., St. Paul, MN (US)
Filed by ECOLAB USA INC., St. Paul, MN (US)
Filed on Feb. 21, 2019, as Appl. No. 16/281,877.
Claims priority of provisional application 62/636,928, filed on Mar. 1, 2018.
Prior Publication US 2019/0271674 A1, Sep. 5, 2019
Int. Cl. G01N 33/18 (2006.01); C23F 11/14 (2006.01); G01N 21/64 (2006.01)
CPC G01N 33/18 (2013.01) [C23F 11/149 (2013.01); G01N 21/64 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method of determining corrosion inhibitor concentration in water, comprising the steps of:
withdrawing a sample of water from an aqueous system, wherein the sample of water is hard water and the sample of water comprises a benzimidazole-based corrosion-inhibitor compound;
diluting the sample of water by adding water to the sample of water, thereby providing a diluted sample of water;
adding an acid to the diluted sample of water, thereby providing an acidified sample of water having a pH of about 1 to about 5;
exposing the acidified sample of water to light energy of a selected excitation wavelength;
measuring an intensity of emitted light about a selected fluorescence emission wavelength;
comparing the intensity of the emitted light to a standard curve, the standard curve comprising a plot of fluorescence emission intensity of the benzimidazole-based corrosion-inhibitor compound versus concentration of the benzimidazole-based corrosion-inhibitor compound; and
determining the concentration of the benzimidazole-based corrosion-inhibitor compound in the acidified sample of water from the standard curve.