Easy-fit ISIS 3 Sample Loops recommended sample introduction timing

Importance of the topic

The precise control of sample introduction timing and flow rates is essential for reproducible and accurate results in ICP-MS analyses. Standardized sample loop volumes and pump speed recommendations streamline method development, reduce variability, and improve laboratory throughput.

Study Objectives and Overview

This technical note presents predefined timing and pump speed settings for Agilent Easy-fit ISIS 3 fixed-volume sample loops used on an Agilent 7900 ICP-MS equipped with an ISIS 3 7-port valve and SPS 4 autosampler. The goal is to help users implement a reliable method quickly and consistently.

Methodology and Instrumentation

• ICP-MS System: Agilent 7900 with ISIS 3 7-port valve
• Autosampler: SPS 4 with standard peristaltic tubing
• Carrier Tubing: 1.02 mm ID peristaltic pump tubing
• Internal Standard/Tune Tubing: 0.25 mm ID peristaltic tubing
• Sample Probe: 1.00 mm ID
• Easy-fit Sample Loops: Volumes 0.25 to 4.00 mL, tubing IDs 1.00 mm and 2.18 mm

Recommended timings were measured by varying loop volumes and pump speeds, then recording acquisition, stabilization, and wash durations.

Main Results and Discussion

Acquisition times increase with loop volume, from 15 s for a 0.25 mL loop up to 645 s for a 4.00 mL loop. A constant stabilization period of 20 s ensures signal equilibration. Probe wash is fixed at 4 s, while loop wash duration corresponds to the uptake pump time at 80% pump speed. For example, a 1.00 mL loop (1.00 mm ID) requires 80 s acquisition, 10 s uptake, 20 s stabilization, 4 s probe wash, and 10 s loop wash. Loops with 2.18 mm ID tubing follow a similar pattern with adjusted timing values.

Benefits and Practical Applications

• Accelerated method development using default loop parameters
• Improved sample throughput and reduced downtime between analyses
• Enhanced reproducibility and minimized carryover risk
• Seamless integration with standard ICP-MS autosampler configurations

Future Trends and Possibilities

Emerging approaches may include real-time signal feedback to dynamically adjust timing, automated optimization routines integrated into instrument control software, and novel loop designs for specialized sample matrices. These advances could enable fully automated, high-throughput ICP-MS workflows in both research and QA/QC laboratories.

Conclusion

The provided timing and pump speed recommendations for Agilent Easy-fit ISIS 3 sample loops serve as a robust starting point for consistent and efficient ICP-MS sample introduction. Users should tailor these settings to their specific applications and consult the ISIS 3 user guide for detailed configuration guidance.

Reference

• Agilent Technologies. Easy-fit ISIS 3 Sample Loops Technical Note, November 2021.