942 Extension Module Vario Prep 2 - Manual

Significance of the Topic

The growing demand for automated ion chromatography in quality control and research laboratories has driven the need for integrated sample preparation. Inline matrix elimination, standard addition and preconcentration reduce manual handling, minimize contamination risk and accelerate throughput, making robust sample preparation modules critical components in modern analytical workflows.

Objectives and Study Overview

This document describes the 942 Extension Module Vario Prep 2, designed to expand a Metrohm 940 Professional IC Vario system. The module adds two key functions – a peristaltic pump for controlled fluid delivery and a six-port switching valve for sample/auxiliary fluid selection – enabling inline matrix elimination, sample transfer and standard addition with preconcentration.

Applied Methodology and Instrumentation

The module integrates via a 40 cm MSB cable (optionally 1 m) into the 940 IC system and is fully managed by MagIC Net software. Sample liquids and reagents are drawn or dispensed by a two-channel peristaltic pump featuring reversible flow at 0–42 rpm and selectable tubing diameters (0.38–1.37 mm ID). A PEEK six-port valve switches between sample and reagent lines in under 100 ms, rated to 350 bar. Installation options include stacking above or below the parent instrument with dedicated base trays and bottle holders.

Used Instrumentation

• 942 Extension Module Vario Prep 2 (order no. 2.942.0020)
• Peristaltic pump with tubing cartridges (6.2755.000)
• Pump tubings in various diameters (Tygon and PharMed®)
• PEEK six-port switching valve
• Connecting cables (6.2156.060, optional 6.2156.070)
• 940 Professional IC Vario with MagIC Net control software

Main Results and Discussion

Integration of the Prep 2 module enables fully automated inline sample preparation directly upstream of the separation system. Users report consistent matrix removal and accurate standard addition without manual sample handling. The reversible peristaltic pump and rapid valve switching afford flexible flow schemes, while MagIC Net’s automatic detection and validation of the module simplify system configuration. Regular maintenance of tubing and filters ensures stable performance.

Benefits and Practical Applications of the Method

• Automated inline matrix elimination reduces operator workload and risk of contamination.
• Standard addition with preconcentration improves quantification in complex matrices.
• Reversible peristaltic pump supports a wide range of applications (dialysis, dilution, transfer).
• Compact modular design allows up to three extension modules per IC system.
• Software-driven control ensures reproducible workflows and centralized data logging.

Future Trends and Applications

Advances in pump tubing materials and miniaturized valves may extend chemical compatibility and increase system uptime. Integration with online detectors, machine-learning-based method optimization and remote system diagnostics will further streamline workflows. Expanded preconcentration strategies and microfluidic sample cleanup are emerging areas for next-generation extension modules.

Conclusion

The 942 Extension Module Vario Prep 2 offers a versatile, software-controlled solution for inline sample preparation in ion chromatography. Its peristaltic pump and six-port valve deliver reliable matrix removal, standard addition and preconcentration, enhancing data quality and laboratory efficiency.

Reference

Metrohm AG. 942 Extension Module Vario / Vario Prep 2 Manual, 8.942.8001EN, August 31, 2017.