A Complete Method for Environmental Samples by Simultaneous Axially Viewed ICP- OES following US EPA Guidelines

Importance of the Topic

Environmental monitoring of water and wastewater demands reliable, high-throughput elemental analysis to ensure regulatory compliance and protect human health and ecosystems. Developing a single, universal method that covers trace to major elements in diverse matrices reduces laboratory workload, cuts operational costs and streamlines data quality management under US EPA guidelines.

Objectives and Overview of the Study

This study aimed to establish a comprehensive analytical protocol for simultaneous axially viewed ICP-OES to quantify 22 US EPA elements in environmental waters and wastewaters. Method validation followed EPA Methods 200.7 and 6010B and CLP ILM04.0/05.0 requirements, focusing on detection limits, linear dynamic range, interference control and automated quality-control workflows.

Methodology and Instrumentation

An Agilent Vista simultaneous ICP-OES with axially viewed plasma and a cooled cone interface was used. Key hardware features included a full-spectrum VistaChip CCD (165–785 nm), robust RF design tolerating up to 5% dissolved solids, SeaSpray concentric nebulizer, peristaltic pump and SPS-5 autosampler with on-line dilution. Software capabilities such as MultiCal and Adaptive Integration provided real-time wavelength selection and optimized integration times to span ppb to percent levels in a single measurement.

Instrumentation

• Agilent Vista simultaneous ICP-OES with axially viewed plasma
• VistaChip CCD detector (165–785 nm, 1 MHz pixel speed, anti-blooming)
• SeaSpray glass concentric nebulizer
• 3-channel peristaltic pump, mass flow controller for nebulizer gas
• Agilent SPS-5 autosampler with on-line dilution capability
• Cooled Cone Interface (nickel cone) to reduce ionization interferences

Key Results and Discussion

Detection limits (IDLs/MDLs) met or exceeded EPA Contract Required Detection Limits (CRDLs) for all 22 elements with a 30 s integration. Linear dynamic range verification showed recoveries within ±5% up to element-specific upper limits (e.g., Ag to 2 mg/L, Ca to 2 000 mg/L). A ten-hour stability study of calibration verification (CCV), interference checks (ICSA/ICSAB), Contract Required Detection Limit tests (CRI) and duplicate/spike samples demonstrated precision better than 2% RSD and recovery within EPA-specified limits. Automated software routines ensured timely action on QC failures, minimizing sample reruns.

Benefits and Practical Applications of the Method

• Single-run quantification of trace and major elements reduces analysis time to ~2.5 min/sample.
• Automated quality-control and on-line dilution lower operator intervention and risk of human error.
• Compliance with multiple EPA protocols in one method simplifies training and documentation.
• Reduced argon consumption and faster throughput enhance cost efficiency in high-volume laboratories.

Future Trends and Potential Applications

Further advancements could integrate spectral deconvolution and machine-learning-based interference correction. Extending the universal method to solid matrices, soils or biological samples via automated sample prep may broaden its applicability. Adaptation to evolving regulatory requirements worldwide will maintain method relevance and foster global environmental monitoring.

Conclusion

The Agilent Vista simultaneous ICP-OES method fulfills rigorous US EPA environmental testing requirements in a single, automated analysis. It delivers robust detection limits, extensive linear dynamic range and reliable long-term performance, offering a versatile solution for modern laboratories facing diverse sample demands.

References

1. US EPA Contract Laboratory Program, Statement of Works for Inorganics, Multi-Media, Multi-Concentration, Document Number ILMO 4.0.
2. ILM05.0 documentation (EPA draft revision of ILM04.0).
3. US EPA Method 200.7, Determination of Metals and Trace Elements in Water and Wastes by ICP-AES, May 1994.
4. US EPA SW-846 Method 6010B, Inductively Coupled Plasma-Atomic Emission Spectrometry, December 1996.
5. Private communication, US EPA regional approval of CsCl2 ionization buffer addition, October 1999.
6. A.P.M. de Win, Journal of Analytical Atomic Spectrometry, Vol. 3, 1988, 487.
7. D. Johnson, Varian Application Note #19, December 1996.
8. Global Vista ICP-OES performance data, Agilent Technologies, internal report.