Analysis of Aqueous Solution by EDX-LE - Performance in Air Atmosphere

Significance of the Topic

Analysis of aqueous solutions for elemental composition is critical in quality control and regulatory compliance. The ability to detect heavy metals and halogens in industrial manufacturing and environmental monitoring supports safety, product quality and adherence to RoHS directives.

Objectives and Study Overview

This study evaluates the performance of the EDX-LE instrument for energy dispersive X ray analysis of an 18 element aqueous standard solution under air atmosphere. Key goals include determination of theoretical lower limits of detection and repeatability for elements from aluminum to lead.

Methodology

Samples of 5 mL standard solutions were mounted under a 5 um polypropylene film. Elemental spectral intensities were acquired with a fixed integration time of 100 seconds. Theoretical lower limits of detection were computed from net and background counts, and repeatability estimates derived from signal statistics. Tested solutions included single element standards at 1000 ppm and 100 ppm, a mixed multi element solution for phosphorus, and a high concentration aluminum chlorine matrix.

Used Instrumentation

• Instrument EDX-LE
• X ray tube Rh target
• Tube voltage 15 kV for light to medium elements and 50 kV for heavier elements
• Detector Si PIN semiconductor
• Collimator aperture 10 mm diameter
• Atmosphere Air
• Integration time 100 sec
• Live time up to 40 percent dead time

Key Results and Discussion

The instrument achieved detection of silicon down to a few hundred ppm and calcium at several ppm in air. Heavy elements such as arsenic were quantified accurately at 1 ppm levels with repeatability under 1 percent. Calculated lower limits of detection generally improved with higher atomic number. The repeatability coefficient of variation ranged from about 0.17 percent for selenium to 9.8 percent for silicon, reflecting matrix and signal effects.

Benefits and Practical Applications

The ability to perform X ray fluorescence in an air atmosphere without liquid nitrogen cooling streamlines compositional analysis in manufacturing quality assurance, pre shipment inspection and RoHS screening. The technique applies to aqueous matrices, organic materials such as resins and films, and solid by products like smelting slags.

Future Trends and Opportunities

Advances may include integration with automation and robotics for high throughput screening, expanded detector technologies for enhanced resolution, AI assisted spectral de convolution and quantification, and adaptation to portable platforms for field analysis. Broader adoption in environmental monitoring and process control in metal and semiconductor industries is anticipated.

Conclusion

The EDX-LE system demonstrates reliable, sensitive elemental analysis of aqueous solutions in air with low detection limits and strong repeatability. Its flexibility and ease of use position it as a valuable tool for laboratories requiring rapid multi element screening and quantitation.