Total elemental analysis of food samples for routine and research laboratories using the Thermo Scientific iCAP RQ ICP-MS

Importance of the topic

The simultaneous determination of nutritional and toxic elements in food is essential for public health and regulatory compliance. A single robust multielement method that covers both macro- and trace-level concentrations streamlines workflows in routine analytical and research laboratories.

Objectives and overview of the study

This study evaluates the performance of the Thermo Scientific iCAP RQ ICP-MS operated in single He KED mode for rapid, high-throughput elemental analysis of diverse food matrices. It demonstrates method sensitivity, accuracy, and reproducibility using certified reference materials.

Methodology and Instrumentation

• Sample preparation: Microwave digestion of 0.5 g rice flour (IRMM-804) and chicken (NCS ZC73016) with HNO₃/HCl, diluted to 50 mL.
• Calibration: Major elements at 25–100 mg/L; minor elements at 25–100 μg/L; internal standards Ga, Rh, Ir.
• Instrumentation: Thermo Scientific iCAP RQ ICP-MS with Peltier-cooled spray chamber, PFA nebulizer, quartz torch, QCell flatapole, and He collision gas in KED mode; Elemental Scientific SC-4 DX autosampler.
• Operating conditions: 1500 W forward power, optimized nebulizer, auxiliary and coolant gas flows, 3 min total acquisition time per sample.

Main results and discussion

• He KED mode effectively removes polyatomic interferences, enabling simultaneous quantification of low-mass (e.g., Li) and high-mass (e.g., Na) elements in a single measurement.
• Method detection limits in the μg/kg range were achieved after 1:100 dilution, sufficient for food safety thresholds.
• Calibration curves exhibited excellent linearity (R²≥0.999) across wide concentration ranges, including high-level Na up to 1000 mg/L using selectable high-resolution mode.
• Analysis of rice flour and chicken reference materials produced results within certified values, with relative standard deviations <2% over five independent replicates during an 8-hour run screening over 150 samples.
• Internal standard signals remained stable throughout extended analysis, illustrating instrument robustness and minimal drift without recalibration.

Benefits and practical applications

This approach offers high sample throughput, broad dynamic range, and reliable interference removal, making it well suited for food safety testing, nutritional profiling, and routine QA/QC in both regulatory and research environments.

Future trends and possibilities

• Integration of triple-quadrupole ICP-MS for resolution of complex interferences.
• Advanced chromatographic coupling for expanded speciation of bioactive and toxic species.
• Enhanced automation and LIMS connectivity for streamlined laboratory workflows.
• Application to a wider variety of complex matrices such as environmental and clinical samples.

Conclusion

The Thermo Scientific iCAP RQ ICP-MS operated in single He KED mode delivers a sensitive, accurate, and high-throughput solution for total elemental and speciation analysis in food, fulfilling stringent requirements for routine and research laboratories.

Reference

• Thermo Fisher Scientific Application Note AN43326: Total elemental analysis of food samples for routine and research laboratories using the Thermo Scientific iCAP RQ ICP-MS.