Combining microdialysis sampling and inductively coupled plasma mass spectrometry for dynamic monitoring of trace metal ions during bacterial growth periods

Abstract

Monitoring the dynamic variations of trace metal ions allows us to understand their roles in basic cellular functions and also in microbial-mediated detoxification of metal pollutants. The objective of this study was to develop an easily operated, simultaneous, and continuous method for dynamic monitoring of trace metal ions during bacterial growth periods. Here, we used a microdialysis (MD) sampling technique combined with detection through inductively coupled plasma mass spectrometry (ICP-MS) to determine and quantify trace metal ions. After optimization, we used a retrodialysis technique and a no-net-flux method to assess the probe recovery and analytical performance of the proposed system. The mean probe recoveries of cobalt, copper, strontium, cadmium, and lead were 64.4, 92.6, 40.8, 84.2, and 54.7%, respectively, with typical precision values of 0.5–6.2, 1.1–7.7, 2.0–6.3, 2.3–7.8, and 1.5–7.8%, respectively. To further evaluate the practical applicability of using our proposed MD/ICP-MS method, we monitored, continuously for 24 h, the dynamic variations of the concentrations of each metal ion in four standardized bacterial species (ATCC 35218, 25922, 25923, 29213). Our analytical results revealed that MD sampling combined with ICP-MS detection had the ability to accurately and continuously monitor the levels of trace metal ions in microbial inoculated culture broths, potentially benefiting research into the bioavailability and detoxification processes of trace metal ions in microbial samples.