Analysis of Environmental Samples with the Agilent 710-ES Following US EPA Guidelines

Significance of the Topic

The determination of trace and major elements in environmental water and soil samples is critical for assessing contamination, guiding remediation strategies, and ensuring compliance with regulatory frameworks such as the US EPA Contract Laboratory Program (CLP). Reliable, high-throughput, multi-element analysis techniques support environmental monitoring, emergency response decisions, and public health protection.

Objectives and Study Overview

This study evaluated the Agilent 710-ES inductively coupled plasma-optical emission spectrometer (ICP-OES) for its ability to perform US EPA CLP ILM05.3 compliant multi-element analysis of water samples. Key goals included verifying detection limits, linear dynamic range, calibration stability, interference correction, and quality control performance according to EPA guidelines.

Methodology and Instrumentation

Water samples and quality control solutions were prepared in 1% v/v HNO₃ and 5% v/v HCl. Calibration standards, blanks, interference check samples (ICS A and B), laboratory control samples (LCS), matrix spikes, and continuing calibration checks were prepared from certified multi-element kits and NIST SRM 1643e. The method detection limits (MDLs) were determined by measuring low-level standards over multiple days, and linear dynamic range (LDR) was assessed up to concentration levels requiring dilution.

Instrumentation Used

• Agilent 710-ES ICP-OES with megapixel CCD detector and axially viewed plasma
• Agilent SPS3 autosampler with online over-range dilution and cesium ionization buffer addition
• SeaSpray nebulizer, glass cyclonic spray chamber, standard axial torch
• ICP Expert II software with MultiCal feature for extended linear range and automated QC protocols

Main Results and Discussion

MDLs for all 22 target elements met or exceeded CLP and contract requirements, ranging from sub-µg/L to µg/L levels. The LDR extended to 50–600 mg/L depending on element, with MultiCal enabling seamless switching between primary and secondary wavelengths without manual dilution. Calibration verification (ICV, CCV) recoveries fell within 90–110%, and CRQL check (CRI) met 70–130% criteria. Interference check samples showed recoveries within ±20%, eliminating the need for inter-element correction factors. LCS and duplicate analyses demonstrated accuracy (80–120% recovery) and precision (RPD ≤ 20%). Matrix spike recoveries ranged from 91–116%, confirming minimal matrix effects. Long-term stability over eight hours showed RSDs below 2%, with CCV recoveries stable across all wavelengths.

Benefits and Practical Applications

• Single-view axial ICP-OES reduces analysis time and cost by eliminating radial measurements or additional techniques
• Simultaneous multi-element detection in under four minutes per sample
• Automated EPA-compliant QC routines minimize operator intervention and ensure data integrity
• Extended dynamic range via MultiCal supports analyses of both trace and major elements without manual dilution

Future Trends and Opportunities

Advances in CCD sensitivity and software automation will further increase throughput and reduce detection limits. Integration with microwave digestion, field-deployable ICP-OES units, and coupling with speciation techniques will expand applications to complex matrices. Machine learning algorithms may optimize interference correction and predictive maintenance to improve long-term performance.

Conclusion

The Agilent 710-ES demonstrates robust compliance with US EPA CLP ILM05.3 requirements for environmental water analysis. Its high sensitivity, broad dynamic range, and automated QC capabilities support fast, accurate, and reliable multi-element determinations, making it a valuable tool in environmental monitoring and regulatory laboratories.

References

1. US EPA CLP ILM05.3 Statement of Work for Multi-Media, Multi-Concentration Inorganic Analysis.
2. US EPA Publication 540-F-04-001, Multi-Media, Multi-Concentration, Inorganic Analytical Service for Superfund, 2004.
3. Dubuisson C., Poussel E., Mermet J.-M., Journal of Analytical Atomic Spectrometry, 1997, 12, 281–286.
4. US EPA Contract Laboratory Program, Exhibit D: Analytical Methods for ICP-AES.