Miniaturized point discharge optical emission spectrometry coupling with solid phase extraction: A robust approach...

In this work, a portable chemical vapor generation point discharge optical emission spectrometry (CVG-PD-OES) system was designed for trace Hg²⁺ monitoring in mung bean sprout samples. The system incorporated selective solid phase extraction (SPE) to enhance the detection sensitivity. Gold nanoparticles (AuNPs) were prepared and utilized to extract trace amounts of Hg²⁺ by forming gold amalgam. Subsequently, the amalgam was desorbed using 5% HCl and introduced into a low-power PD-OES system analysis via CVG. A low limit of detection (LOD) of 0.16 ng mL^-1 was obtained with a linear range of 0.5-6 ng mL^-1. The well-designed system was successfully utilized for monitoring trace Hg²⁺ in the growth of mung beans. The results indicated that the Hg²⁺ in mung bean sprouts was continuously decreased during growth based on the metabolism. Furthermore, the risk assessment conducted implied a negligible hazard quotient, suggesting that the observed levels of exposure posed minimal risk.