Performance comparison of solution anode glow discharge coupled with Pt/gas jet cathode for determining the Pb and Zn in blood.

Abstract

A solution anode glow discharge (SAGD) was developed using either a Pt rod or gas (N2, Ar, He) jet. Taking the detection of Pb and Zn as an example, the relationship between plasma characteristics and analytical performance is clarified. The results showed that there is a significant hierarchical difference in analytical performance, namely He > Ar > N2 > Pt. This difference stems from the spatial distribution of the plasma and the efficiency of plasma energy conversion into analyte excitation rather than just the power consumption, which provides mechanistic guidance for designing next-generation miniaturized excitation sources. The helium jet-SAGD (He-SAGD) generates a spatially uniform plasma with efficient energy utilization and minimal molecular energy loss, thereby reducing the spectral interference. Compared with Pt rod-SAGD, the He-SAGD enhances the sensitivity by 8.4-10.8 times and improves the limit of detection by 9.2-11.4 times, along with good precision (RSD <2.5%), outstanding stability and strong anti-interference. The measurement results of He-SAGD for blood samples are good agreement with ICP-AES and satisfactory recovery (86.3%-112.1%). The He-SAGD features a compact device, low cost, and high precision, which has great potential for in-situ and online monitoring of trace heavy metals in complex samples.