Compact Non-Suppressed Ion Chromatograph

What is the Compact Non-Suppressed Ion Chromatograph?

A compact non-suppressed ion chromatograph measures conductivity directly using low-conductivity eluents such as phthalate, benzoate or dilute nitric acid, without a suppressor. It offers lower purchase and operating cost for routine mg/L screening of common anions and cations, where trace-level sensitivity is not required.

Overview

Non-suppressed IC relies on the difference in conductivity between analyte and a weakly conducting eluent, such as 2.5 mM phthalic acid at pH 4 for anions or 2–3 mM nitric or tartaric acid for cations. Because the background is 10–100 µS/cm, noise is higher and detection limits are typically 0.05–0.5 mg/L, roughly ten times higher than suppressed systems. There is no suppressor, so maintenance and regenerant needs are reduced, the flow path is simple, and the instrument can be a compact benchtop unit with an integrated pump, column oven and conductivity cell, sometimes with an integrated autosampler. Gradient elution is not practical because eluent changes cause baseline drift. The system suits process control, teaching laboratories, food and beverage quality checks, and fertilizer or electroplating bath monitoring where concentrations are above 0.1 mg/L.

How does it work?

An ion chromatograph pumps an aqueous eluent, such as carbonate/bicarbonate or hydroxide for anions and methanesulfonic acid for cations, through a guard and analytical column containing a resin with fixed charged functional groups. Sample ions compete with eluent ions for the exchange sites, and ions with higher affinity are retained longer. After the column, a suppressor, either a chemically regenerated or electrolytic membrane device, converts the eluent to water or a weakly conducting form and converts analytes to their highly conducting acid or base forms, sharply reducing background conductivity and improving sensitivity. A conductivity cell then measures the signal. Other detectors include UV at 210 nm for bromide and nitrate, pulsed amperometry for carbohydrates, and post-column reaction for transition metals. Gradient elution with an eluent generator extends the range of ions per run. Software integrates peaks against multi-point calibrations.

What are the key features?

• Direct conductivity detection without suppressor, reducing consumables and maintenance
• Integrated benchtop design combining pump, column oven and conductivity cell in one housing
• Compatible with phthalate, benzoate and nitric acid eluents and low-capacity columns
• Isocratic operation with short warm-up and baseline stabilization time
• Optional integrated autosampler holding 24–50 vials for unattended runs

What are the technical specifications?

A typical compact non-suppressed ion chromatograph configuration offers flow rate range of 0.1–2.0 mL/min, maximum operating pressure of 25 MPa, detector type of Non-suppressed conductivity, detector range of 0–1000 µS/cm, detector noise of ≤5 nS/cm and injection volume of 10–100 µL. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Compact Non-Suppressed Ion Chromatograph is used in teaching and training laboratories, electroplating bath and process monitoring, fertilizer and food mineral content, routine screening above 0.1 mg/L and ion analysis in cooling water. Across the wider Ion Chromatography class, laboratories also deploy it for anions and cations in drinking and wastewater, trace ions in power plant and semiconductor ultrapure water and counter-ion and impurity analysis in pharmaceuticals.

Which standards and certifications apply?

Relevant standards and methods include US EPA Method 300.0, US EPA Method 300.1, ISO 10304-1, ISO 14911, ASTM D4327, USP <1065> Ion Chromatography, ASTM D7359, GB/T 8538 and IEC 61010-1. Certification candidates for this model are CE, ISO 9001 manufacturing and RoHS; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Use 18.2 MΩ·cm deionized water and filter samples to 0.45 µm or 0.2 µm, since particulates and organic contamination damage columns. Keep eluent containers under CO₂-protective traps when using hydroxide, as carbonate uptake changes retention. Regenerate or replace suppressors and eluent generator cartridges following manufacturer guidance, and never run a suppressor dry. Verify conductivity cell temperature stability, typically controlled to 35 °C. Qualify the system with OQ tests for flow accuracy, conductivity response and injection precision per USP <1058>. Prepare standards from certified reference materials and run a calibration check standard every 10–20 samples.

How do I select the right Compact Non-Suppressed Ion Chromatograph?

Select a non-suppressed system for routine analysis at mg/L levels where budget and simplicity matter. For trace ions, regulatory compliance testing or gradients, choose a suppressed or reagent-free system. In an RFQ specify target ions, concentration range, column type, required detection limit and whether an autosampler is needed.

How does it compare with other Ion Chromatography variants?

Key decisions are suppression type, eluent supply and detector range. Suppressed conductivity gives the lowest detection limits, often sub-µg/L for common anions, and is preferred for trace or regulated work. Non-suppressed systems cost less and suit routine mg/L screening. Reagent-free systems generate hydroxide or methanesulfonic acid electrolytically from deionized water, which improves retention-time reproducibility and gradient capability without manual eluent preparation. Dual-channel systems run anions and cations in parallel from one autosampler to double throughput. Combustion IC adds an automated furnace for halogens and sulfur in solids and liquids. Also evaluate autosampler capacity, sample preparation inline such as matrix elimination, column compatibility with your methods, and software features for compliance with USP <1065> and EPA 300.1.