AutoDilution using Chromeleon 7 CDS software and partial loop injection

AutoDilution Using Chromeleon 7 CDS and Partial Loop Injection

Importance of the Topic

Analytical laboratories often encounter samples with analyte concentrations exceeding their calibration range, particularly in complex matrices such as wastewater. Manual detection, dilution, and reanalysis of these out-of-range samples are laborious and error-prone. AutoDilution integrated within Chromeleon 7 CDS Intelligent Run Control automates this workflow, improving data quality and operational efficiency.

Study Objectives and Overview

• Implement AutoDilution with partial loop injections to handle samples above calibration limits.
• Demonstrate sequence configuration in Chromeleon 7 CDS for automatic dilution decisions.
• Showcase time savings and improved reliability compared to manual methods.

Methodology and Used Instrumentation

• Software: Thermo Scientific™ Chromeleon™ 7 Chromatography Data System with Intelligent Run Control (IRC) and AutoDilution module.
• Autosampler: Thermo Scientific™ Dionex™ AS-AP with partial loop capability (250 µL syringe, 1200 µL buffer loop; vial size 1.5 mL; dispense 5 µL/s; draw 10 µL/s).
• IC Systems: Dionex™ ICS-5000+ HPIC, Dionex™ Integrion™ HPIC or Thermo Scientific™ Dionex™ Aquion™.
• Injection Modes: Full loop for initial injection (e.g., 100 µL), partial loop for reinjection (e.g., 10 µL).

Main Results and Discussion

By defining a System Suitability Test (SST) case with AutoDilution conditionals, Chromeleon 7 CDS evaluates each injection against calibration limits. Samples exceeding thresholds automatically trigger reinjection using the Partial Loop method and a reduced volume. This approach eliminated manual intervention for out-of-range samples, streamlined sequence setup, and maintained result accuracy. Users observed consistent detection of high-concentration outliers and reliable reinjection without additional operator input.

Benefits and Practical Applications

• Enhanced productivity: automatic detection and reinjection eliminate manual dilution steps.
• Improved data integrity: consistent application of thresholds and methods reduces human error.
• Flexibility: multiple conditionals and injection volumes can be defined per analyte.
• Cost savings: reduced analyst time and reagent use for repeated manual dilutions.

Future Trends and Potential Applications

Advances may include fully automated vial-to-vial dilutions, integration with AI algorithms for dynamic threshold setting, and broader compatibility with diverse chromatographic platforms. Combining AutoDilution with online sample cleanup and real-time data evaluation could further accelerate high-throughput environmental, pharmaceutical, and food-safety analyses.

Conclusion

AutoDilution within Chromeleon 7 CDS and partial loop injection greatly simplifies the handling of samples exceeding calibration ranges. By automating reinjection logic, laboratories benefit from faster workflows, reduced errors, and higher confidence in quantitative results without additional hardware requirements.