Rapid Multi-Elemental Analysis of Fertilizers using the Agilent 5110 VDV ICP-OES

Importance of the Topic

Cultivating high-yield crops requires precise nutrient management through fertilizers. Over- or under-application of nutrients can harm plant health or reduce yields. Therefore, rapid and reliable multi-element analysis of fertilizers is critical for agricultural quality control and environmental protection.

Objectives and Study Overview

This study demonstrates the rapid determination of 21 macro- and micro-nutrients in fertilizers using the Agilent 5110 Vertical Dual View (VDV) ICP-OES with the Advanced Valve System (AVS 7). The method follows AOAC Official Method 2017.02 and evaluates accuracy, precision, detection limits, and sample throughput under high-throughput laboratory conditions.

Instrumentation

• Agilent 5110 VDV ICP-OES with Advanced Valve System 7 (AVS 7) and SPS 4 autosampler.
• Easy-fit vertical torch with dual-view (axial and radial) and solid-state radio frequency (SSRF) plasma.
• Vista Chip II detector for continuous wavelength coverage (167–785 nm).
• ICP Expert software with Fitted Background Correction (FBC) and IntelliQuant acquisition mode.
• Mars 6 microwave digestion system (CEM) for sample preparation.

Methodology

• Sample preparation: 0.50 g fertilizer digested in 9 mL HNO₃ and 3 mL HCl, microwave-digested per AOAC 2017.02 and diluted to 100 mL (12% reverse aqua regia matrix).
• Calibration: Multi-element working standards prepared in matching acid matrix; linear calibration achieved (R² > 0.999) with multiple wavelengths and FBC to correct spectral interferences.
• Internal standard: Yttrium (5 ppm) with auto-alignment torch to ensure reproducible results across instruments and operators.

Key Results and Discussion

• Method Detection Limits (MDLs) ranged from 0.12 mg/kg (Cd, V) to 24.67 mg/kg (K).
• NIST SRM 695 recoveries were within ±10% for all elements except Al, due to incomplete digestion.
• Spike recovery tests on a commercial fertilizer yielded 94–106% recoveries, confirming method accuracy.
• Long-term stability: 478 spiked samples analysed over 6.5 h without recalibration, with RSDs between 1.0 and 3.4%.
• Sample throughput: 49 s per sample (18 L argon), reducible to 36 s per sample (13.2 L argon) using synchronous vertical dual view (SVDV) mode.
• IntelliQuant semiquantitative scan identified up to 70 elements in under 15 s, providing a heat map of elemental concentrations for quality assurance.

Benefits and Practical Applications

• High throughput and reduced downtime with AVS 7 switching valve and SSRF plasma, lowering operating costs.
• Wide linear dynamic range allows simultaneous analysis of major and trace elements without multiple dilutions.
• Automated background correction (FBC) and simplified user interface ensure consistent results across varying operator skill levels.
• IntelliQuant mode adds semiquantitative data for non-routine elements, enhancing sample screening and method development.

Future Trends and Potential Applications

• Integration of real-time data analytics to further automate quality control and regulatory compliance.
• Expansion of semiquantitative scanning to support rapid detection of emerging contaminants in fertilizer matrices.
• Development of miniaturized or portable ICP-OES systems for field-based fertilizer testing.
• Enhanced chemometric models to predict crop-specific nutrient requirements based on multi-element profiles.

Conclusion

The Agilent 5110 VDV ICP-OES equipped with AVS 7 and state-of-the-art detection and software tools provides a robust, rapid, and accurate solution for multi-element fertilizer analysis. The method meets regulatory requirements, offers high throughput with minimal maintenance, and supports comprehensive quality assurance through advanced background correction and semiquantitative capabilities.

References

1. AOAC Official Method 2017.02: Arsenic, Cadmium, Calcium, Chromium, Cobalt, Copper, Iron, Lead, Magnesium, Manganese, Molybdenum, Nickel, Selenium, and Zinc in Fertilizers, AOAC International, 2017.
2. AOAC Official Method 2006.03: Arsenic, Cadmium, Cobalt, Chromium, Lead, Molybdenum, Nickel, and Selenium in Fertilizers, AOAC International, 2009.
3. Agilent Technologies, Fitted Background Correction (FBC) – Fast, Accurate, and Fully Automated Background Correction, Technical Overview, 2016, 5991-4836EN.
4. Agilent Technologies, Rapid Sample Assessment and Simplified Method Development with IntelliQuant, Technical Overview, 2017, 5991-6876EN.