Online, Rapid Measurement of Pb²⁺ and Hg²⁺ Ions in Water Based on Quantum Dot Fluorescence Quenching Method

A novel method and device for detecting heavy metal ions in water using the principle of quantum dot fluorescence quenching based on a 405nm semiconductor laser had been designed. This technique produced fluorescence-stimulated emission of heavy metals in water by combining interdisciplinary expertise from the fields of chemistry and optics. The detection was quick, easy, and capable of monitoring the level of heavy metal ions in water continuously online. The experimental results demonstrated that the Hg²⁺ concentration exhibited good linear relationships within the low range of 0.001-0.2 mg/L(R
²
=0.998) and the high range of 0.2-2 mg/L(R
²
=0.992). The Pb²⁺ concentration range of 0.0.005–5 mg/L also exhibited a strong linear association (R
²
=0.997). The online detection system for Hg²⁺ and Pb²⁺ responded within 60 seconds and demonstrated good short-term stability and repeatability, fulfilling the demands for quick detection.