Performance Comparison of the Agilent 1290 Infinity II Multicolumn Thermostat with the Agilent 1290 Infinity Thermostatted Column Compartment

Significance of the Topic

The precise and stable control of column temperature is a cornerstone of high-performance liquid chromatography (HPLC). Minor temperature fluctuations can lead to significant retention time shifts, impacting reproducibility, resolution, and method robustness. The Agilent 1290 Infinity II Multicolumn Thermostat introduces enhanced usability and thermal performance, addressing the needs of modern analytical laboratories.

Objectives and Study Overview

This study compares the retention time accuracy and chromatographic performance of the Agilent 1290 Infinity II Multicolumn Thermostat (MCT) against the earlier Agilent 1290 Infinity Thermostatted Column Compartment (TCC). Six sulfonamide compounds, known for their sensitivity to temperature, were analyzed under isocratic and gradient conditions at varied temperatures (21–60 °C) and flow rates (0.3–2 mL/min) to assess retention time shifts and resolution.

Methodology and Instrumentation

The experiments employed an Agilent 1290 Infinity II LC system consisting of:

• Flexible pump (G7104A)
• Multisampler (G7167B)
• Multicolumn Thermostat (G7116B) with Quick-Connect heat exchangers
• Thermostatted Column Compartment (G1316C) with low-dispersion heat exchangers
• Diode Array Detector (G7117B)

Columns included ZORBAX RRHD Eclipse Plus C18 (2.1×100 mm, 1.8 µm), ZORBAX Eclipse Plus C18 (3×100 mm, 3.5 µm), and Poroshell 120 EC-C18 (4.6×50 mm, 2.7 µm). OpenLAB CDS ChemStation controlled the system. Solvents were LC-grade water and acetonitrile with 0.1 % TFA; analytes were six sulfonamides prepared in aqueous solution.

Main Results and Discussion

Under isocratic conditions (40 °C, 1 mL/min), retention time deviations between MCT and TCC were below 2.1 % for all peaks. In gradient mode, at 0.3 mL/min and temperatures of 25, 40, and 60 °C, maximum deviations reached 3.6 %. Tests at higher flow rates and different column formats showed even smaller shifts (<1.9 % at 1 mL/min; <0.8 % at 2 mL/min). Across all conditions, no loss of resolution was observed. The MCT consistently produced slightly earlier elution, attributed to optimized air thermostatting and minimized radial temperature gradients.

Benefits and Practical Applications

• Seamless method transfer from older compartments with retention time shifts within acceptable tolerances.
• Quick-Connect fittings enable fast column changes and reduced downtime.
• Improved accessibility via removable front door and flexible opening positions.
• Reduced peak broadening through uniform temperature control.

Future Trends and Possibilities

Advancements in LC thermostatting may include integrated smart diagnostics, real-time temperature mapping, and predictive control algorithms driven by machine learning. Further miniaturization of column compartments and interfaces could enhance throughput in UHPLC applications, while expanded compatibility with multiplexed columns may support high-capacity screening and complex sample analyses.

Conclusion

The Agilent 1290 Infinity II Multicolumn Thermostat delivers performance equivalent or superior to the prior Thermostatted Column Compartment. It maintains retention time stability below 5 % deviation under varied chromatographic conditions, meeting industry standards for method robustness. Coupled with enhanced usability features, the new thermostat represents a reliable upgrade for modern analytical laboratories.

References

• Schneider S. Performance Characteristics of the Agilent 1290 Infinity II Multicolumn Thermostat. Agilent Technologies Technical Overview; 2015. Pub. No. 5991-5533EN.
• Muehlebach A. Advance efficiency with new Agilent 1290 Infinity II Multicolumn Thermostat. Access Agilent Newsletter; May 2015.