Be-original break new ground: Fluorescence sensing of humic acid in natural water and soil by pitaya seed carbon dots

Illustration of the process and mechanism of determining HA. • ·Using biological matrix as carbon source, pitaya seed carbon dots (P-CDs) were synthesized for the first time. • ·The P-CDs were successfully used in the detection of humic acid. • ·The fluorescence quenching mechanism of P-CDs by humic acid was revealed. • ·A novel and rapid method for the detection of humic acid was presented. Pitaya seed carbon dots (P-CDs) with good biocompatibility were synthesized by hydrothermal method using natural biological matrix as carbon source, which applied to the detection of humic acid (HA) for the first time. So far, there is no report on the use of biomatrix-derived carbon dots for the detection of HA. This method can bring less pollution to the detection process of HA, which is very important to ensure lower cost, environmental safety and minimized energy consumption. In addition, it was worth noting that, based on the concept of green chemistry, the preparation process of P-CDs is simple, and the fluorescence method is used for analysis. Based on the fluorescence resonance energy transfer (FRET) mechanism, the detection of HA in water and soil can be realized in a short time. The results matched those of high-performance liquid chromatography (HPLC), suggesting that it shows great potential in water and soil quality monitoring.