Effectively increase sample turnover and boost data confidence using triple quadrupole ICP-MS

Importance of the topic

Reliable monitoring of both toxic and nutritional elements in food is essential to protect public health and ensure regulatory compliance. Interferences in inductively coupled plasma mass spectrometry (ICP-MS) can compromise data accuracy, leading to false positives and reanalysis delays. Triple quadrupole (TQ-ICP-MS) technology offers a robust solution to these challenges, enhancing confidence in trace metal quantification at high throughput.

Objectives and Study Overview

This study evaluates the advantages of TQ-ICP-MS, specifically the Thermo Scientific iCAP TQe system, for determining toxic metals such as arsenic, cadmium, mercury, and lead in food matrices. It compares interference removal, detection limits, and sample turnaround for standard single quadrupole collision/reaction cell (CRC) modes against TQ-O2 operation.

Methodology

Analytes were measured using helium-based kinetic energy discrimination (KED), hydrogen as a reactive gas, or oxygen in a TQ-ICP-MS configuration. Instrument performance was verified daily using automated tuning routines. Sample introduction employed a MicroMist nebulizer, quartz cyclonic spray chamber at 3 °C, and Ni sampler/skimmer cones. Software-assisted method development guided gas selection and mass filtering.

Instrumentation

• ICP-MS systems: Thermo Scientific iCAP TQe and iCAP RQ
• Nebulizer: Borosilicate glass MicroMist, 400 µL/min at 40 rpm
• Spray chamber: Quartz cyclonic, cooled at 3 °C
• Injector: 2.5 mm quartz
• Interface: Ni sampler and skimmer cones, 3.5 mm insert
• RF power: 1550 W
• Collision/reaction gases: He (4.3 mL/min KED), O2 (0.34 mL/min TQ-O2), H2 for complementary tests

Main Results and Discussion

• TQ-O2 eliminated false positives from rare earth element interferences on 75As and 78Se by mass filtering in Q1 and reaction with O2, unlike KED which showed significant errors in SRM apple and tomato leaf digests.
• Cadmium analysis (111Cd) was compromised by 95Mo16O+ in KED mode, whereas TQ-O2 completely suppressed MoO interferences even at elevated Mo levels.
• Detection limits for common elements (e.g., Li, Na, Mg, K, Mn, Ni, Cu, Zn) were equivalent or improved in TQ-O2 compared to KED; several analytes displayed up to fivefold lower limits.
• Single-mode TQ-O2 operation reduced total runtime by 10–20% compared to dual-gas single quadrupole methods, by avoiding gas switching and extended CRC evacuation.

Benefits and Practical Applications

The TQ-ICP-MS O2 mode delivers full interference removal across the mass range, lowers detection limits, and enables higher sample throughput without additional infrastructure. Laboratories can avoid downtime from unexpected interferences and streamline workflows for food safety testing and other trace elemental analyses.

Future Trends and Possibilities

Adoption of triple quadrupole ICP-MS with optimized gas regimes is expected to expand in routine food and environmental laboratories. Further integration with chromatographic speciation, automated method development, and artificial intelligence for real-time interference correction will enhance analytical robustness and productivity.

Conclusion

Combining mass filtering with oxygen cell gas in TQ-ICP-MS significantly improves interference suppression and detection capabilities for critical food contaminants. This approach offers reliable, high-throughput analyses, minimizes false positives, and simplifies method implementation compared to conventional single quadrupole CRC methods.

References

• Thermo Fisher Scientific. Smart Note 44415: iCAP RQ ICP-MS.
• Thermo Fisher Scientific. Smart Note 44452: iCAP TQ ICP-MS.
• Thermo Fisher Scientific. Application Note 44474: Trace metals in food via triple quadrupole ICP-MS.
• Thermo Fisher Scientific. Application Note 43285: Arsenic and selenium in environmental samples by TQ-ICP-MS.