Patent ID: 8961798
Filing Date: 2015-02-24
Classification: C02F,Y10S

Abstract:
1. A method for measuring a concentration of persulfate and sulfur dioxide in an ultrapure water stream comprising: introducing persulfate to the ultrapure water stream having a TOC concentration of less than about 25 ppb; measuring a first conductivity of the ultrapure water stream in a first conductivity cell of a first sensor; irradiating the ultrapure water stream to provide an irradiated ultrapure water stream; measuring a second conductivity of the irradiated ultrapure water stream in a second conductivity cell of the first sensor; calculating the concentration of persulfate in the ultrapure water stream based in part on the first conductivity measurement and the second conductivity measurement of the first sensor; introducing sulfur dioxide to the irradiated ultrapure water stream; measuring a first conductivity of the irradiated ultrapure water stream comprising sulfur dioxide in a first conductivity cell of a second sensor; irradiating the ultrapure water stream comprising sulfur dioxide to provide an irradiated ultrapure water stream comprising sulfur dioxide; measuring a second conductivity of the irradiated ultrapure water stream comprising sulfur dioxide in a second conductivity cell of the second sensor; and calculating the concentration of sulfur dioxide in the irradiated ultrapure water stream comprising sulfur dioxide based in part on the first conductivity measurement and the second conductivity measurement of the ultrapure water stream comprising sulfur dioxide of the second sensor.