Novel Approach to Sample Preconcentration by Solvent Evaporation in Flow Analysis

Area of Science:

• Analytical Chemistry
• Environmental Chemistry

Background:

• Trace metal analysis in environmental samples requires sensitive and efficient preconcentration techniques.
• Existing methods often involve complex procedures or limitations in sample throughput.

Purpose of the Study:

• To develop and optimize a flow-mode preconcentration module integrated with sequential injection analysis (SIA) for enhanced spectrophotometric detection.
• To evaluate the system's performance for the determination of chromium(III) and zinc in water matrices.

Main Methods:

• Development of a membraneless evaporation preconcentration module operating under reduced pressure.
• Integration with a sequential injection system for automated sample handling and analysis.
• Optimization of system parameters for signal enhancement and precision.
• Application in spectrophotometric determination of Cr(III) and capillary electrophoresis with spectrophotometric detection for Zn.

Main Results:

• Achieved signal enhancement factors of approximately 10 for Cr(III) determination with good precision (8.4% and 5.1% CV for precision and intermediate precision).
• Signal enhancement factors up to 20 were obtained depending on the initial sample volume.
• Demonstrated applicability for Zn determination in certified reference materials (drinking water, wastewater) with a detection limit of 0.025 mg L⁻¹ and precision < 6% CV.

Conclusions:

• The developed membraneless evaporation preconcentration system offers a sensitive and effective approach for trace metal analysis in environmental water samples.
• The system's integration with SIA and spectrophotometric/capillary electrophoresis detection provides a robust platform for accurate and precise metal determination.
• This method holds potential for routine environmental monitoring and quality control applications.