Analysis of Fertilizer

Significance of Fertilizer Trace Analysis

In modern agriculture, the balanced application of nutrients and strict control of contaminants in fertilizer materials is essential for crop health and environmental protection. Analytical methods capable of simultaneous determination of major and trace elements enable efficient quality assurance aligned with legal thresholds.

Objectives and Study Overview

The present study evaluates the performance of the ICPE-9000 inductively coupled plasma atomic emission spectrometer for quantifying principal nutrient elements and toxic trace constituents in sludge-based fertilizers. A comparative analysis with a high-resolution sequential ICP instrument (ICPS-8100) was also conducted to verify accuracy and precision.

Methodology and Instrumentation

Sample preparation involved:

• Ashing of 5 g fertilizer in a muffle furnace at 400 °C for 24 h
• Acid digestion with aqua regia on a hot plate followed by hydrochloric acid addition
• Volume adjustment to 200 mL and addition of yttrium as an internal standard
• Preparation of spike-and-recovery test samples through fortification with multi-element standard solution

Instrumental conditions were set as follows:

• RF power 1.2 kW, cooling gas 14 L/min, plasma gas 1.2 L/min, carrier gas 0.8 L/min
• Coaxial nebulizer and cyclone mist chamber with axial and radial viewing options
• Confirmation analysis performed on the ICPS-8100 under similar operational settings

Main Results and Discussion

Quantitative results for fertilizer samples A, B and C demonstrated excellent agreement between the ICPE-9000 and ICPS-8100 systems. Recovery rates for analytes such as As, Cd, Cr, Cu, Ni, Pb, Ti and Zn ranged from 94 % to 110 %, meeting regulatory limits (eg As 2 mg/kg, Cd 0.02 mg/kg). High concentrations of matrix elements (Ca, Al, P, S) did not interfere with accurate quantitation. Calibration curves exhibited strong linearity with correlation coefficients above 0.9999 for all target wavelengths.

Benefits and Practical Applications

This ICP emission spectrometry approach delivers rapid multi-element analysis in a single run, enhancing throughput for fertilizer quality control laboratories. Its wide dynamic range accommodates both macronutrients and trace contaminants, supporting compliance with the Fertilizer Management Law.

Future Trends and Possibilities

Emerging developments may include coupling with preconcentration or chromatographic separation, online automated sample introduction, and advanced chemometric algorithms to address complex fertilizer matrices. Portable ICP emission units could enable onsite monitoring and rapid decision-making.

Conclusion

The ICPE-9000 system provides robust, sensitive and accurate multi-element analysis for sludge-derived fertilizers, delivering performance comparable to high-resolution sequential instruments. It effectively supports regulatory compliance and operational efficiency in fertilizer testing.

Instrument Used

ICPE-9000 inductively coupled plasma atomic emission spectrometer
ICPS-8100 high-resolution sequential ICP emission spectrometer

Reference

Fertilizer Management Law Law No 127 of May 1 1950, revised Law No 150 of December 1 2004
Fertilizer Analysis Methods Ministry of Agriculture, Forestry and Fisheries National Institute of Agro-Environmental Sciences, 1992 Revision