Highly sensitive rapid and portable detection of Hg²⁺ and CH₃Hg⁺ in environmental samples based on boron nitrogen...

Mercury species are extremely toxic, even at trace levels, to the ecological environment and human health. Herein, the facile, cost-effective, highly sensitive and portable approaches for detecting Hg²⁺ and CH₃Hg⁺ were successfully developed by integrating the innovative synthesis of boron nitrogen co-doped silicon quantum dots (BN-SiQDs) with a portable smartphone. The introduction of boron and nitrogen elements offered additional electrons and accelerated the electron transfer between the BN-SiQDs and Hg²⁺ or CH₃Hg⁺, significantly increasing the sensitivity of detection and substantially reducing the detection limit (LOD, 0.38 nM for Hg²⁺ and 0.52 μM for CH₃Hg⁺). The results of the recovery assay in tap water and seawater demonstrated the accuracy, repeatability, and applicability of the established smartphone-based methods for detecting CH₃Hg⁺ and Hg²⁺ ions in environmental waters, with recovery rates in the range of 90.2%-106% and relative standard deviations (RSDs) of 3.14%-8.98%. The proposed method for the detection of Hg²⁺ or CH₃Hg⁺ offered a promising tool for on-site environmental monitoring.