Determination of elemental nutrients in DTPA extracted soil using the Agilent 5110 SVDV ICP-OES

Significance of the Topic

Soil micronutrient and heavy metal profiling is critical for optimizing crop productivity and ensuring food safety. DTPA extraction combined with ICP-OES analysis allows reliable assessment of bioavailable nutrient levels and potential toxin loads in agricultural soils.

Objectives and Study Overview

This work demonstrates the application of the Agilent 5110 Synchronous Vertical Dual View ICP-OES to quantify Cu, Fe, Mn, Zn, Co, Ni, Cd, and Pb in DTPA-extracted soil. A secondary goal compares sample throughput and argon consumption with and without the Agilent Advanced Valve System (AVS 6).

Methodology and Instrumentation

• Extraction protocol: 10 g soil shaken for 120 min with 20 mL of DTPA–CaCl2–TEA solution (pH 7.3), followed by filtration.
• Instrumentation: Agilent 5110 SVDV ICP-OES with 27 MHz SSRF plasma, demountable dual-view torch (1.8 mm injector), SeaSpray nebulizer, double-pass cyclonic spray chamber, and SPS 4 autosampler.
• Operating parameters: RF power 1.20 kW; plasma and auxiliary gas flows 12 L/min and 1.0 L/min; 5 s read time, three replicates per sample; multi-element calibration with R² > 0.999.

Main Results and Discussion

Calibration exhibited excellent linearity across target ranges with R² > 0.999. Method detection limits ranged from 0.002 to 0.025 mg/kg. Spike recoveries for all elements fell within ±10% of expected values. Integration of AVS 6 reduced analysis time from 59 s to 30 s and argon consumption per sample by approximately 49%, while maintaining accuracy.

Benefits and Practical Applications

The method combines high sensitivity and wide dynamic range with robust sample handling, facilitating high-throughput soil fertility and contamination screening in agricultural and environmental laboratories. Automated torch alignment and valve switching enhance reproducibility and reduce operator dependency.

Future Trends and Potential Applications

Emerging directions include coupling ICP-OES with speciation techniques, portable and field-deployable ICP instruments for on-site testing, and integration with automated sample preparation platforms. Advances in data analytics and AI may further streamline method development and result interpretation.

Conclusion

The Agilent 5110 SVDV ICP-OES, with or without AVS 6, delivers a robust, sensitive, and efficient workflow for determining micronutrients and heavy metals in DTPA-extracted soils. The approach enhances laboratory productivity and resource efficiency without compromising analytical performance.

Reference

• AVS tech note, Agilent publication, 2016, 5991-6863EN
• John Cauduro, Ultra-high speed analysis of soil extracts using an Advanced Valve System on an Agilent 5110 SVDV ICP-OES, Agilent publication, 2016, 5991-6853EN