Determination of Sb in Sediment and Road Soil

Significance of the Topic

Antimony is extensively employed as a flame retardant, pigment and catalyst in industrial applications. Its widespread use leads to environmental release via smelting operations, road traffic emissions, incineration and waste disposal. Recognized as a priority pollutant by regulatory agencies and harmful at trace levels, monitoring antimony in soils and sediments is essential for assessing ecological risk and ensuring compliance with environmental standards.

Objectives and Study Overview

This application note details the development and validation of a graphite furnace atomic absorption spectrometry method for quantifying trace antimony in sediment and road soil samples. The performance of an Agilent 240Z spectrometer with transverse Zeeman background correction is evaluated and compared with inductively coupled plasma mass spectrometry results.

Used Instrumentation

• Agilent 240Z Zeeman graphite furnace atomic absorption spectrometer
• GTA 120 pyrolytic graphite tube atomizer
• PSD 120 programmable sample dispenser autosampler

Methodology

Sample collection targeted four matrices: suspended particulate matter from river water, long term sediment trap deposits, freeze-dried river sediments and urban road deposited sediments sieved to retain particles under 200 micrometers. A three-phase microwave block digestion in PTFE vessels employed HF, HClO4, HCl and HNO3 reagents to achieve complete mineralization. The dry residue was dissolved in 2 percent nitric acid.

Graphite furnace conditions were optimized using the instrument software wizard to select ash and atomization temperatures at 932 and 2195 degrees Celsius. A mixed modifier of magnesium and palladium nitrates was co-injected. Key spectrometer parameters included a wavelength of 217.6 nanometers, Zeeman background correction, and a 30 microliter total injection volume. Standard additions were performed on the first sample to generate calibration curves with spiked levels of 10, 20 and 40 micrograms per liter.

Main Results and Discussion

• Calibration slopes for samples 1 to 4 ranged from 0.00332 to 0.00343 with correlation coefficients above 0.9990, indicating consistent response factors.
• Repeatability RSD values were below 6 percent for triplicate measurements across all matrices.
• Accuracy was confirmed by comparison with ICP-MS, showing recovery within plus or minus 10 percent.
• Long term stability over a 6 hour sequence yielded RSD values under 3.5 percent.
• Detection and quantification limits in solution were 1 and 2.9 micrograms per liter, corresponding to 0.5 and 1.4 milligrams per kilogram in the solid samples. Characteristic mass was 24 picograms.

Benefits and Practical Applications

The method delivers the sensitivity required for trace antimony monitoring at lower operational cost compared to ICP-MS. The transverse Zeeman correction combined with optimized furnace parameters ensures robust performance. Employing a single standard addition calibration reduces sample turnaround time and argon consumption. This approach is suitable for routine environmental surveillance and industrial quality control.

Future Trends and Applications

Advancements in autosampler workflows, surface response optimization and novel chemical modifiers may further enhance detection limits and throughput. Integration with data processing algorithms and remote monitoring systems will expand the applicability of graphite furnace AAS for heavy metal screening in emerging environmental matrices and industrial effluents.

Conclusion

The Agilent 240Z graphite furnace AAS method provides accurate, precise and stable determination of low level antimony in sediments and road soils. Performance comparable to ICP-MS, combined with reduced cost and simplified calibration, supports its adoption for routine environmental analysis.

References

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4. L Vov BV Electrothermal Atomization The way towards absolute methods of atomic absorption analysis Spectrochimica Acta Part B 1978 33 153-193
5. Slavin W and colleagues The stabilized temperature platform furnace concept Atomic Spectrometry 1981