Determination of Trace Element Contents in Solid Environmental Matrices using Collision/Reaction Cell ICP-MS

Objectives of this study were to: a) optimize EPA-3052 microwave digestion method using a c/r ICP-MS method by adjusting combinations of acids, digestion temperature and duration; b) validate the c/r ICP-MS method for multi-element analyses to determine their total concentration in solid matrices; and c) set up a robust single-step partial extraction method by using the c/r ICP-MS method. Here, special emphasis has been given to total trace element analyses of marine sediment samples from the Back Biloxi Bay, MS to monitor the effects of Hurricane Katrina on the region. This study confirmed that the amount of acid extraction not only depends on the applied digestion method including different types and combinations of acids, but also the type of element, its origin (natural or anthropogenic) and its chemical form. Optimized conditions for total digestion have been selected as-Acid: HNO₃+ HF + HCl (10:3:2); Temperature: 180°C; Power: 1600 W; and Duration: 15 minutes. The dilute acid (single-step) microwave digestion methods extract a significant amount of trace elements from sediment solid matrices, therefore these methods can lead to overestimation of the amount of trace elements that might be released into the environment. The dilute acid (0.5 M HCl) (single-step) “cold” extraction method can provide valuable information for evaluating the amount of trace metal that might become remobilized and/or bioavailable. Total trace element contents of marine sediments from Back Biloxi Bay, collected monthly following Hurricane Katrina, revealed a wide range of variation, but no apparent temporal trends. Acknowledgement: This study was supported by NOAA-NIUST-NA05NOS4261163.