Elemental Analysis of Animal Feed and Fertilizers Produced From Insects

Significance of the Topic

The use of insects such as Black Soldier Fly larvae to convert food and organic waste into protein-rich feed and organic fertilizers aligns with sustainable agriculture goals. Determining elemental composition of substrates, larvae, insect meal, and frass is crucial for safety, regulatory compliance, and optimizing regenerative farming practices.

Objectives and Overview of the Study

This application note describes a multi-element analysis of five sample types—organic waste, BSF larvae, insect meal, unprocessed frass, and frass pellets—using the Agilent 5800 Vertical Dual View ICP-OES. Twenty-six elements, including macronutrients (N, P, K, Ca, Mg, S) and trace contaminants (As, Cd, Pb), were quantified to support method development, ensure product safety, and inform fertilizer quality.

Methodology and Instrumentation

Sample Preparation:

• Aliquots of each matrix were homogenized, weighed (~0.5 g), and digested with HNO₃ and H₂O₂ in a high-temperature microwave protocol (250 °C, 25 min).
• Digests were diluted to 50 mL with deionized water.

Calibration and Quality Control:

• Multi-range calibrations were generated for major and trace elements; MultiCal extended dynamic ranges for Ca and Mg.
• Continuing Calibration Blank and Verification solutions checked accuracy every 10 samples.
• Limits of detection (LODs) and quantification (LOQs) were established from repeated blank measurements.

Data-processing Tools in ICP Expert Pro:

• IntelliQuant Screening provided rapid semi-quantitative scans to select calibration ranges and interference-free wavelengths.
• Fitted Background Correction (FBC) automatically corrected complex background structures.
• Intelligent Rinse optimized rinse times between samples to prevent carryover and save resources.

Used Instrumentation

• Agilent 5800 VDV ICP-OES with vertical torch and Vista Chip III CCD detector.
• SeaSpray concentric nebulizer, double-pass cyclonic spray chamber, Easy-fit semi-demountable torch.
• SPS 4 autosampler for sample introduction.

Main Results and Discussion

Instrument Performance:

• All calibrations achieved R² ≥ 0.9996 across 26 elements.
• LOQs ranged from low μg/kg levels for trace metals to single-digit mg/kg for major elements.
• Long-term stability over an eight-hour sequence showed QC recoveries within ±4%, with no instrumental drift.

Accuracy and Recovery:

• NIST 1566b Oyster Tissue reference material recoveries were within 90–104% for elements above LOQ.
• Post-digestion spikes in frass samples yielded recoveries of 90–108% across analytes.

Elemental Profiles:

• Frass and frass pellets were rich in N, P, K, Ca, and Mg, supporting their use as organic fertilizers.
• BSF larvae and insect meal contained elevated protein‐associated elements such as P and S, confirming their value as feed ingredients.
• Contaminant levels (As, Cd, Pb) remained below regulatory thresholds in all sample types.

Benefits and Practical Applications of the Method

• Rapid, multi-element quantification in diverse insect-derived matrices supports process optimization and quality control.
• Smart software tools reduce method development time and minimize spectral interferences for non-expert users.
• High sensitivity and robust performance enable compliance with safety standards for feed and fertilizer products.

Future Trends and Opportunities

• Integration of routine multi-element screening in insect farming operations to track nutrient recycling and environmental impact.
• Expansion of ICP-OES methods to emerging insect species and waste streams for tailored fertilizer formulations.
• Development of regulatory frameworks for insect-derived fertilizers and feeds, leveraging robust analytical approaches.

Conclusion

The Agilent 5800 VDV ICP-OES, combined with intelligent software functions, provides a fast, reliable, and accurate approach for comprehensive elemental analysis in insect-related samples. The method delivers high sensitivity, low detection limits, and excellent long-term stability, supporting sustainable insect farming and the production of safe, nutrient-rich feed and organic fertilizers.

References

1. Deen, S. N. E.; van Rozen, K. et al. Bioconversion of Different Waste Streams by Black Soldier Fly Larvae. Insects 2023, 14(2), 204.
2. IPIFF. Valorisation of insect frass as fertiliser – EU Insect Producer Guidelines; 2024.
3. Riles, P. Multi-Element Analysis of Trace Metals in Animal Feed using ICP-OES; Agilent 5994-0215EN.
4. Oppedisano, D. Rapid Multi-Elemental Analysis of Fertilizers using the Agilent 5110 VDV ICP-OES; Agilent 5994-0600EN.