Detecting Contaminants in Water Based on Full Scattering Profiles within the Single Scattering Regime

Clean water is essential for maintaining human health.To ensureclean water, it is important to use sensitive detection methods thatcan identify contaminants in real time. Most techniques do not relyon optical properties and require calibrating the system for eachlevel of contamination. Therefore, we suggest a new technique to measurewater contamination using the full scattering profile, which is theangular intensity distribution. From this, we extracted the iso-pathlength(IPL) point which minimizes the effects of scattering. The IPL pointis an angle where the intensity values remain constant for differentscattering coefficients while the absorption coefficient is set. Theabsorption coefficient does not affect the IPL point but only attenuatesits intensity. In this paper, we show the appearance of the IPL insingle scattering regimes for small concentrations of Intralipid.We extracted a unique point for each sample diameter wherein lightintensity remained constant. The results describe a linear dependencybetween the angular position of the IPL point and the sample diameter.In addition, we show that the IPL point separates the absorption fromthe scattering, which allows the absorption coefficient to be extracted.Eventually, we present how we used the IPL point to detect the contaminationlevels of Intralipid and India ink in concentrations of 30-46and 0-4 ppm, respectively. These findings suggest that theIPL point is an intrinsic parameter of a system that can be used asan absolute calibration point. This method provides a new and efficientway of measuring and differentiating between various types of contaminantsin water.