Rapid and Highly Sensitive Detection of Trace Chromium and Copper in Tea Infusion Using Laser-Induced Breakdown Spectroscopy Combined with Electrospinning Technology

Tea infusion, as the world's second most popular beverage, is increasingly favored by people. However, tea plants accumulate heavy metals from the soil during growth, which are gradually transferred to the leaves and subsequently decomposed into the tea infusion after soaking in hot water. Long-term consumption of tea infusion containing heavy metals may lead to severe health issues, such as liver dysfunction and cancer. Therefore, rapid, precise, and highly sensitive detection of heavy metals in tea infusion becomes crucial for human health. Traditional methods, such as AAS, suffer from long detection cycles, high costs, and the risk of secondary pollution from chemical extraction reagents. Thus, this paper presents a method using LIBS combined with electrospinning technology (LIBS-ES) to detect trace amounts of Cr and Cu in tea infusion. The electrospun nanofiber membranes (ENM) were modified with AuNPs and AgNPs, achieving ultra-sensitive detection of Cr and Cu. The experiment results show that the limits of detection for Cr and Cu are 5 μg/L and 9 μg/L, respectively. Moreover, this method was successfully applied to the detection of Cr and Cu in seven different types of tea infusion, achieving recovery rates of 99%-112% and 97%-115%, respectively. The method demonstrated good performance even under the interference of other ions at various concentrations, providing a reference for the rapid and highly sensitive detection of heavy metals in tea infusion.