Patent ID: 7909963

Claim:
A method for measuring the concentration of hydrophobic contaminants distributed in a paper pulp suspension, the method comprising: adding a lipophilic fluorescent dye to the paper pulp suspension including fibers and hydrophobic contaminants, the lipophilic fluorescent dye interacting with the hydrophobic contaminants exhibiting fluorescence, whereas the lipophilic fluorescent dye interacting with the fibers exhibiting substantially no fluorescence; submitting the paper pulp suspension including a mixture of fibers, hydrophobic contaminants, and lipophilic fluorescent dye to light characterized by a wavelength exciting the lipophilic fluorescent dye interacting with the hydrophobic contaminants to produce light emission signals; detecting the light emission signals by observing at least one of peaks of fluorescence against time and an average of fluorescent intensities; and evaluating the detected light emission signals to measure the hydrophobic contaminants by correlating the detected light emission signals to the concentration of contaminants.