Patent ID: 7534394
Filing Date: 2009-05-19
Classification: G01N,Y10S,Y10T

Abstract:
1. A flow injection analysis apparatus for determining the concentration of hydrogen peroxide in a solution contained in a chamber, comprising: a chamber containing said solution; a means for removing a sample of solution from said chamber; a first fixed volume sample loop connected to said means for removing a sample of solution, to receive said sample of solution; a dilution chamber containing a known volume of an electrolyte connected to said first fixed volume sample loop to receive and dilute said sample of solution; a means for removing a sample of diluted solution from said dilution chamber; a second fixed volume sample loop connected to said means for removing a sample of diluted solution, to receive the sample of diluted solution; a titration cell containing a reference electrode, a working electrode, and a means for stirring a liquid, said titration cell being connected to said second fixed volume sample loop to receive the sample of diluted solution; a voltmeter connected to said reference electrode and working electrode to perform periodic measurements of the titration cell potential; a programmable digital processing unit connected to said voltmeter, wherein said digital processing unit receives the periodic measurements of the titration cell potential from the voltmeter; and a means for introducing a volume of titrant into the titration cell at a fixed rate, said means being connected to and controlled by said digital processing unit, wherein said digital processing unit performs a plurality of calculations of the differential in titration cell potential expressed as dE/dV, where E is the titration cell potential and V is the volume of titrant, such that when the differential in titration cell potential changes abruptly the digital processing unit stops the means for introducing a volume of titrant into the titration cell from introducing any more titrant into the titration cell and then calculates the concentration of hydrogen peroxide in the sample of solution.