WHAT IT IS
Sample preparation in ion chromatography (IC) encompasses all steps required to make a sample suitable for injection and analysis. It includes filtration, dilution, matrix elimination, preconcentration, and derivatization, depending on the sample type and target analytes. Preparation can be performed manually or automated via autosamplers, inline modules, or multi-valve configurations.
HOW IT WORKS
Proper sample prep ensures compatibility with the IC system and prevents damage to columns, suppressors, or detectors. It also improves accuracy and reproducibility, especially when dealing with complex matrices or trace-level analysis.
Manual injection – Entry-level and compact IC systems often use manual valves with fixed or variable sample loops. Injection volumes are typically defined by loop size, and switching is performed by the user.
Autosamplers – Integrated or optional autosamplers allow for high-throughput, unattended operation. They support precise volume control, washing cycles, and variable injection programs. Advanced models offer temperature-controlled racks and compatibility with vials of different sizes.
Inline sample preparation – Many IC systems support inline filtration, dilution, ultrafiltration, dialysis, or matrix elimination. These steps are carried out automatically between sampling and injection using valves or modules (e.g., MISP, RFIC-ESP, Dosino-controlled systems).
2D-IC integration – For high-matrix or trace analysis, systems may include column-switching or multi-dimensional setups to separate and remove interfering components prior to detection.
KEY FEATURES
Injection flexibility – Supports manual valves, fixed loops, autosamplers, or hybrid modes.
Inline automation – Filtration, dilution, and matrix removal can be performed inline without manual steps.
Autosampler compatibility – Systems may support cooling, rack configurations, and programmable injections.
Sample volume control – Injection ranges from sub-microliter to high-volume loops, depending on the application.
Expandable modules – Some systems are upgradeable with preconcentration, derivatization, or valve-based prep sequences.
IMPACT ON PERFORMANCE
Reproducibility – Automated and inline prep reduces variability in injection volume and matrix handling.
System protection – Proper filtration and matrix elimination protect columns and suppressors from fouling.
Throughput – Autosamplers and inline prep reduce operator workload and enable 24/7 operation.
Sensitivity – Preconcentration and dilution steps allow for better detection of trace ions.
Method robustness – Standardized preparation workflows improve cross-lab comparability and regulatory compliance.
CHALLENGES AND LIMITATIONS
Manual limitations – Manual injection is less reproducible and unsuitable for high-throughput labs.
Hardware complexity – Multi-valve or 2D-IC configurations require additional setup and software control.
Contamination risk – Improper sample handling or injector carryover can affect accuracy.
Sample compatibility – Viscous, particulate-rich, or reactive matrices may require offline pretreatment.
Upgrade cost – Adding inline modules or high-end autosamplers increases system complexity and price.