A rapid method for detecting trace Rb and Cs in high-salinity brines by ICP-MS equipped with an all-matrix sampling...

Area of Science:

• Analytical Chemistry
• Environmental Science
• Geochemistry

Background:

• Analyzing trace elements rubidium (Rb) and cesium (Cs) in high-salinity brines is challenging due to severe matrix suppression effects.
• Traditional methods require complex sample preparation, including matrix matching or standard addition, increasing analysis time and cost.

Purpose of the Study:

• To develop a rapid, highly sensitive, and efficient method for determining trace Rb and Cs in high-salinity brines.
• To overcome the matrix suppression effect in brine samples using a novel sampling device.

Main Methods:

• Utilized inductively coupled plasma mass spectrometry (ICP-MS) integrated with an all-matrix sampling (AMS) device for online argon gas dilution.
• Implemented a simplified sample pretreatment procedure (single-step dilution without acid-washed containers).
• Employed dynamic internal standard correction with yttrium (Y) and rhodium (Rh) and optimized instrument parameters.

Main Results:

• The AMS system effectively reduced matrix suppression (<1.5%) from 35 g·L^-1 salinity, enabling direct quantification.
• Achieved excellent limits of detection (LOD: 0.039 μg·L^-1 for Rb; 0.005 μg·L^-1 for Cs) and high precision (RSD <5%).
• Demonstrated analytical efficiency improvement by over 70% due to simplified sample preparation.

Conclusions:

• The developed ICP-MS method with AMS offers a robust, sensitive, and operationally efficient solution for analyzing Rb and Cs in extreme high-salinity environmental samples.
• This approach eliminates the need for conventional matrix-matching or standard addition, streamlining the analytical workflow.