Patent ID: 8068227

Claim:
A method for measuring the concentration of a substance in a solution, said substance having an absorption at 300 nm or less, said method comprising: i) transmitting ultraviolet light of wavelength 300 nm or less from a light source which light source is a light emitting diode which emits light at a wavelength of 300 nm or less, through a band pass filter; ii) passing said ultraviolet light emanating from said band pass filter through a beam-splitter; iii) diverting a first portion of the light by the beam-splitter and quantifying the electromagnetic radiation of said first portion with a reference detector to obtain a reference value; iv) irradiating a known path length of the solution with a second portion of the light passing through the beam splitter; v) quantifying the electromagnetic radiation transmitted through the solution with a sample detector to obtain a sample value; and vi) determining the absorbance (A) from said sample value and said reference value and using said absorbance to obtain a measuring value for the concentration by a dose-response curve; wherein said light source is a light emitting diode which emits light of wavelength of 300 nm or less; further wherein said substance is separated from one or more compounds present in said solution by chromatography prior to step (i).