Thermo Scientific iCAP TQ ICP-MS: Typical limits of detection

Importance of the Topic

Inductively Coupled Plasma–Mass Spectrometry (ICP-MS) is a cornerstone technique for trace element analysis across environmental, food safety, clinical and industrial laboratories. Achieving low detection limits while effectively removing spectral interferences is critical for accurate quantification at ultratrace levels. The Thermo Scientific iCAP TQ ICP-MS combines triple quadrupole technology with controlled reaction chemistry to deliver superior interference removal and extended dynamic range, streamlining method development for demanding analytical tasks.

Objectives and Study Overview

This study evaluates typical instrument detection limits (IDLs), background equivalent concentrations (BECs) and method performance of the iCAP TQ ICP-MS. Both single-quadrupole (SQ-STD, SQ-KED) and triple-quadrupole (TQ-NH₃, TQ-H₂, TQ-O₂) modes are compared to illustrate interference removal capabilities for challenging sample matrices.

Methodology and Instrumentation

• Sample Preparation: Multi-element standards (0, 0.2, 5, 10 µg/L) prepared gravimetrically in 2% HNO₃ and 0.5% HCl.
• Instrument Configuration: iCAP TQ ICP-MS with quartz concentric nebulizer, Peltier-cooled cyclonic spray chamber (2.7 °C), quartz torch, Ni sampler/skimmer cones, and Teledyne CETAC ASX-560 autosampler.
• Operating Modes: SQ-STD and SQ-KED (He), TQ-NH₃, TQ-H₂ and TQ-O₂ reaction modes using default autotune settings in Qtegra ISDS software.

Main Results and Discussion

The iCAP TQ ICP-MS demonstrates significant reduction in IDLs and BECs when using TQ modes versus SQ:

• Basic SQ vs SQ-KED: Elements such as Fe, Ca and K show up to two orders of magnitude lower IDLs in SQ-KED versus SQ-STD.
• Arsenic in Co Matrix (10 mg/L): SQ-KED delivers a BEC ~7.9 µg/L; TQ-O₂ mass-shift reduces BEC to 18 ng/L and IDL to 8 ng/L.
• Cadmium in Mo Matrix (10 mg/L): SQ-KED BEC ~3.9 µg/L; TQ-O₂ on-mass improves BEC to 1.6 ng/L and IDL to 3.2 ng/L.
• Titanium in 1% H₂SO₄: TQ-NH₃ cluster formation yields a BEC of 7.3 ng/L versus 62.3 µg/L in SQ-KED.
• Selenium in 2% HNO₃: TQ-H₂ on-mass mode achieves IDLs of 0.4 ng/L compared to 19.7 ng/L in SQ-KED.

Benefits and Practical Applications

The triple quadrupole configuration offers:

• Exceptional interference removal across diverse matrices
• Ultralow detection limits for environmental, clinical and food safety analyses
• Flexible gas chemistries for mass-shift and on-mass modes in a single method
• Simplified method development with autotune and robust tuning algorithms

Future Trends and Applications

Emerging directions include coupling TQ-ICP-MS with automated sample preparation and chromatographic separation, exploring novel reaction gases and tailored reagent chemistries, and integrating real-time data analysis and machine learning for adaptive interference correction. Such advances will further expand capabilities for speciation studies, ultratrace isotope ratio analysis and high-throughput quality control.

Conclusion

The Thermo Scientific iCAP TQ ICP-MS significantly outperforms conventional single-quadrupole systems by leveraging triple quadrupole technology and reaction-cell chemistries. It delivers robust interference removal, lower detection limits and streamlined workflows, making it a powerful solution for trace elemental analysis in both research and routine applications.

Reference

• Vincent T. Technical Note 43287: Thermo Scientific iCAP TQ ICP-MS – Typical limits of detection. Thermo Fisher Scientific; 2017.