A research group led by Prof. WU Guojun from the Xi’an Institute of Optics and Precision Mechanics of the Chinese Academy of Sciences developed a turbidity compensation technique for correcting the influence of suspended particles in fluorescence detection of natural water samples. The study was published in Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy.

Fluorescence technology has been an efficient tool for algae detection due to its rapid and direct detection capabilities. However, in natural waters, turbidity caused by suspended particles leads to scattering, absorption, and shielding effects, resulting in deviations in fluorescence measurements. 

Since the fluorescence characteristics, scattering properties, and instrument configurations vary across environments, a universal compensation model for turbidity effects is unattainable.

In this study, researchers investigated fluorescence variations of Platymonas helgolandica var. tsingtaoensis (Pt) and Synechococcus elongatus (Se) under turbidity interference. Experiments revealed that, under the same detection conditions, the fluorescence intensity of Se increased with turbidity, while that of Pt decreased.

By analyzing the turbidity interference mechanisms on the fluorescence spectra of these algae, researchers separated the interference caused by turbidity particles into scattering intensifying and scattering-absorption attenuating components and corrected them separately. The total turbidity effect was modeled as a combination of these components.

Researchers established separate compensation models for Se and Pt, achieving a post-compensation prediction error of less than 4%. They then proposed a method for compensation without prior turbidity knowledge by utilizing the relationship between turbidity levels and scattered light intensity, reducing reliance on specialized turbidity measurement instruments.

This study will significantly improve the accuracy and applicability of fluorescence detection in turbid waters.