Are you measuring ICP-OES samples more than once?

Reducing Remeasurements in ICP-OES Analysis

Significance of the Topic
ICP-OES is widely applied in quality control across food, water and industrial laboratories.
Unexpected remeasurements waste analyst time, increase costs, delay results and can harm lab reputation.
Surveys indicate an average of 15% of samples are remeasured, yet many labs do not track this metric.

Objectives and Study Overview
This report identifies the most common causes of ICP-OES sample remeasurements and provides practical prevention strategies.
It integrates survey data, cost impact analyses and a structured cause–solution review to improve analytical efficiency.

Methodology and Instrumentation
A qualitative analysis of user experiences, cost calculations and systematic troubleshooting procedures was conducted.

Used Instrumentation

• Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES)
• Autosampler with peristaltic pump tubing
• Options for axial and radial plasma viewing
• Certified reference materials and internal standard solutions

Key Findings and Discussion
Instrument-Related Issues

• Nebulizer blockages from particulates or salt deposits can be avoided by sample filtration, optimized probe depth, argon humidification and larger nebulizers.
• Torch injector fouling causes signal drift; prevent by using wider injector torches, conducting daily automated performance checks and scheduling regular cleaning.
• Carryover between samples leads to contamination; mitigate with automatic rinse cycles, frequent calibration blank checks and extended rinse durations.
• Out-of-spec instrument settings and utility failures degrade performance; address with daily performance tests and verification of gas flows, RF power and pump speed.
• Incorrect method parameters such as uptake delay and pump speed require manual timing verification and method configuration validation.
• Dirty preoptic windows and spray chambers reduce sensitivity and precision; include these in routine maintenance schedules.
• Peristaltic pump tubing wear, leaks or air bubbles cause poor precision; inspect tubing condition, tension and clamps before each analysis.

Sample-Related Issues

• Spectral interferences occur when overlapping emission lines or hidden elements produce false highs; mitigate by selecting multiple emission lines, applying inter-element correction or using spectral deconvolution models.
• Calibration errors from pipetting inaccuracies and contaminated reagents can be reduced through pipette recalibration, rigorous glassware cleaning and use of multi-element standards.
• Contamination of blanks, standards and samples can be detected with reagent blanks, laboratory control samples and strict vessel cleaning protocols.
• Sample preparation mistakes and mix-ups are prevented by standardized SOPs, inclusion of control spikes and clear reagent tracking.
• High-matrix samples cause enhancement or suppression; use internal standard correction, sample dilution, matrix-matched calibrations or radial plasma viewing.
• Overrange samples require less sensitive wavelengths, integrated auto-dilution features or radial view analysis to avoid manual dilutions.

Benefits and Practical Applications
Implementing these measures reduces rerun rates, frees up two or more weeks per analyst per year, lowers consumable costs and speeds up result delivery.
Laboratories can reallocate resources to value-added tasks, improve client satisfaction and strengthen regulatory compliance.

Future Trends and Opportunities

• Integrated auto-dilution and dynamic rinse routines in ICP-OES software.
• AI-driven spectral deconvolution and predictive interference correction.
• Advanced real-time diagnostics and predictive maintenance alerts.
• Greater automation of sample preparation with direct LIMS connectivity.
• Development of vertical torches and next-generation nebulizer technologies.

Conclusion
A structured approach combining preventive maintenance, robust QC protocols and method optimization can significantly reduce ICP-OES remeasurement rates.
Consistent monitoring and clear SOPs ensure reliable data, increased efficiency and improved laboratory performance.