Determination of available nutrients in soil using the Agilent 4200 MP-AES

Significance of the Topic

Soil fertility testing via multielement analysis provides critical insight into nutrient availability, guiding precise fertilizer management. The Agilent 4200 MP-AES offers enhanced sensitivity, safety and cost efficiency by using nitrogen plasma generated on-site, eliminating flammable gases and enabling broad dynamic range measurements in one run.

Objectives and Study Overview

This study evaluates three extraction procedures to quantify exchangeable cations and micronutrients (including boron) in soil using the Agilent 4200 MP-AES. Results are benchmarked against FAAS and ICP-OES to demonstrate accuracy and workflow improvements.

Methodology and Instrumentation

• Sample Preparation:
  • DTPA extraction for Cu, Fe, Mn, Zn: 0.005 M DTPA, 0.01 M CaCl2, 0.1 M TEA, pH 7.3; shake 120 min; filter
  • 1 M ammonium acetate extraction for Na, K, Ca, Mg: pH 7.0; shake 30 min; filter
  • Hot water CaCl2 extraction for B: 0.01 M CaCl2; heat 120 °C, 15 min; filter
• Instrumentation:
  • Agilent 4200 MP-AES with nitrogen from Agilent 4107 generator
  • Double-pass cyclonic spray chamber, OneNeb nebulizer, SPS 3 autosampler
  • Peltier-cooled CCD detector, fast sequential mode, MP Expert software for interference correction
  • Operation: 3 replicates; pump rate 15 rpm; uptake delay 35 s; rinse time 30 s; stabilization time 15 s
• Calibration:
  • Cu, Zn: 1–5 ppm; Fe, Mn: 5–25 ppm; Na, K, Ca, Mg: 1–100 ppm; B: 0.25–1 ppm

Key Results and Discussion

• Linear calibration and detection across a wide range, e.g. K up to 100 ppm with MP-AES vs. FAAS limit.
• Measured values for all elements agree within ~5% of FAAS and ICP-OES benchmarks.
• Unified single-instrument analysis of macro- and micronutrients, including boron, without mode or lamp changes.

Benefits and Practical Applications

• Lower operating costs and improved safety by eliminating flammable gases.
• Unattended operation via on-site nitrogen generation.
• Enhanced sensitivity and dynamic range reduce dilutions and risk of contamination.
• Simplified workflow for routine soil fertility and environmental analyses.

Future Trends and Applications

Integration with automated sampling systems, field-deployable platforms, and data analytics for precision agriculture, along with expanded roles in environmental monitoring and high-throughput soil mapping.

Conclusion

The Agilent 4200 MP-AES delivers accurate, sensitive, and efficient multielement soil analysis, outperforming traditional FAAS in dynamic range and safety. Its unified measurement approach streamlines laboratory workflows and supports advanced agronomic and environmental testing.

Reference

• Agilent Technologies. Determination of available nutrients in soil using the Agilent 4200 MP-AES. Application Note, Publication 5991-5675EN, May 2015.