Patent ID: 8379205

Claim:
A system for determining a concentration of at least one substance in a fluid, the system comprising: a pulsed light source to generate a first light pulse comprising at least one predetermined wavelength that is absorbed differently in the fluid depending on the concentration of the substance; a light pulse splitter to receive the first light pulse from the pulsed light source and to split the first light pulse into at least a second light pulse and a third light pulse, the second light pulse comprising the at least one predetermined wavelength, the second light pulse and the third light pulse being separated in time as well as wavelength, wherein the second light pulse and the third light pulse pass through the fluid along a first light path such that the substance in the fluid partly absorbs the second light pulse; a reference light pulse generating device to generate at least one reference intensity that bypasses the fluid along a second light path without passing through a reference sample, the at least one reference intensity comprising the at least one predetermined wavelength and having a delay in time relative to the partly absorbed second light pulse; a detector to detect the intensity of the partly absorbed second light pulse and the at least one reference intensity; and a comparator to compare the detected partly absorbed second light pulse with the detected at least one reference intensity to thereby determine the concentration of the at least one substance in the fluid.