Analysis of drinking water in compliance with EPA Method 200.8, Revision 5.4

Significance of the Topic

The analysis of drinking water in accordance with EPA Method 200.8 Revision 5.4 is essential for safeguarding public health and meeting regulatory requirements. High sample throughput, rigorous quality control and reliable detection limits are critical for environmental laboratories tasked with monitoring a diverse range of water matrices.

Objectives and Study Overview

This application note demonstrates the performance of the Thermo Scientific iCAP RQplus ICP-MS for the determination of dissolved elements in surface water, ground water and drinking water. The study follows the procedural guidelines of EPA Method 200.8 Revision 5.4 and evaluates instrument sensitivity, accuracy, precision and robustness over extended unattended operation.

Methodology and Instrumentation Used

Instrumentation and workflow

• Thermo Scientific iCAP RQplus ICP-MS equipped with built-in Argon Gas Dilution for automatic aerosol dilution.
• MicroMist nebulizer, cyclonic quartz spray chamber, quartz torch and high-matrix skimmer cones.
• Thermo Scientific iSC-65 autosampler for automated sample introduction.
• Qtegra Intelligent Scientific Data Solution Software for instrument control, data processing and QC management.

Analytical approach

• Standard mode operation without collision cell in accordance with method restrictions.
• Internal standardization using 6Li Sc Y Tb and Bi to correct drift and matrix effects.
• Calibration with seven concentration levels per analyte and continuous online addition of internal standard.
• Correction equations applied for key polyatomic interferences following method recommendations.

Main Results and Discussion

Detection limits and linearity

• Instrument detection limits were below regulatory Maximum Contaminant Levels for all target elements.
• Correlation coefficients exceeded 0.999 for 21 analytes, demonstrating excellent linear response over the working range.

Accuracy and precision

• Laboratory fortified blanks and fortified matrices returned recoveries within 90–105%, meeting acceptance criteria.
• Certified reference material SLRS-5 analyses yielded recoveries between 93% and 110% with RSD below 5%.

Quality control and robustness

• Laboratory reagent blanks and quality control samples analyzed every 15 injections showed consistent results over an 18-hour run of more than 300 samples.
• Internal standard recoveries remained within 80–115%, demonstrating effective matrix compensation.
• Automatic argon gas dilution minimized interface cone deposition and signal drift, ensuring long-term stability.

Benefits and Practical Applications

The automated dilution feature reduces maintenance intervals by limiting matrix buildup, while high throughput and unattended operation enhance laboratory productivity. Comprehensive QC tools within the software simplify compliance with method protocols and support regulatory reporting.

Future Trends and Potential Uses

Advances in gas dilution technology and software driven automation will further streamline environmental monitoring workflows. Integration with laboratory information management systems and cloud-based data analytics may enable real-time compliance tracking and remote instrument supervision.

Conclusion

The Thermo Scientific iCAP RQplus ICP-MS with built-in argon gas dilution delivers sensitive, accurate and robust analysis of diverse water samples in full compliance with EPA Method 200.8 Revision 5.4. Its automated QC and dilution capabilities support high throughput and reliable long-term performance.

Reference

• U S EPA Method 200.8 Revision 5.4 Guidance Manual
• National Primary Drinking Water Regulations NPDWR
• National Secondary Drinking Water Regulations NSDWR