High‑Selectivity Anion Exchange IC Column (Acetate & Inorganic Anions)
CromSil™ IonX-2 is a high-selectivity anion exchange column for ion chromatography, purpose-built to tackle challenging separations of inorganic anions and small organic acid anions (like acetate) in a single analysis. It leverages the same robust PS/DVB polymer backbone and quaternary ammonium functionality as the IonX series, but with a tuned capacity/interaction profile that delivers enhanced resolution for closely eluting species. The IonX-2 provides exceptional selectivity – for example, it can separate an array of common anions (fluoride, chloride, nitrite, bromide, nitrate, phosphate, sulfate) plus acetate with ease. Like its IonX counterparts, it is compatible with carbonate/bicarbonate eluents and optimized for use with a suppressor for conductivity detection. Its chemical sturdiness allows pH 0–14 operation and solvent tolerance, ensuring method flexibility and easy cleanup. For analysts who need to resolve organic acids in the presence of high concentrations of inorganic anions (or vice versa), CromSil™ IonX-2 emerges as an indispensable column, offering precision and reliability in every run.
In practice, the IonX-2 is typically run with standard carbonate/bicarbonate eluents and a suppressor, just like other anion IC columns. What users observe is an improved resolution for certain critical pairs of anions. For example, in environmental analyses, acetate can be a common interference – IonX-2 ensures that acetate (often present from natural organic matter or sample preservation) is well-resolved from important inorganic anions. A demonstrated separation on IonX-2 shows eight distinct anion peaks: fluoride, acetate, chloride, nitrite, bromide, nitrate, phosphate, and sulfate, all baseline separated in under 15 minutes. This is achieved by the column’s finely tuned selectivity and high plate count, which spreads peaks out just enough to prevent overlap while maintaining reasonable run times.
The high efficiency and reproducibility of IonX-2 come from its uniform particle size and stable packing. Even with its special selectivity, it does not compromise on efficiency – peaks remain narrow and Gaussian, which is essential for good detection limits and quantitation. The column’s polymeric substrate and PEEK construction impart the same chemical resilience: full pH range stability means one can use strong alkaline or acidic regen/cleaning steps if needed, and the column won’t be harmed by occasional organic solvent use (e.g., to flush out hydrophobic contaminants). IonX-2 likewise benefits from the use of a guard cartridge (CromSil Guard for IonX-2) to capture sample impurities and thus keep that selectivity and efficiency optimal over a long lifetime. The guard is especially advised when dealing with samples high in particulate or organic content (like environmental samples), as it will prevent fouling of the exchange sites that could alter the delicate selectivity balance.
In summary, IonX-2’s technology offers a specialized solution in the IC column landscape: it retains the robustness and broad compatibility of a modern polymeric IC column while pushing the envelope on separating power for mixed inorganic/organic anion systems.
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Parameter
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Description/Value
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Column Chemistry
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Strong Anion Exchange (Polymer-Based) – High-Selectivity PS/DVB anion-exchange resin with quaternary ammonium functional groups. The resin formulation is optimized for selectivity, giving unique retention behavior for certain ions (notably acetate).
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Dimensions
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250 mm × 4.6 mm ID standard analytical column (PEEK housing). Provides sufficient length for high resolution. (Custom shorter versions may be available for faster runs if some resolution compromise is acceptable.) The column connects with standard 1/16” fittings.
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Particle Size
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~9 µm highly spherical polymer beads. Ensures high column efficiency (thousands of theoretical plates) for sharp peaks despite the focus on selectivity. Packing density and consistency are tightly controlled for reproducibility.
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Exchange Capacity
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Medium-to-high (proprietary tuning). The capacity is set to balance retention of early vs late eluters, which is key to IonX-2’s distinct separation profile. It can handle typical sample ion loads, but extremely high concentrations of a single anion might slightly shift relative retention (as is true for any IC column). Suppressed IC mode is recommended for best performance with carbonate eluents.
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Recommended Eluents
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Sodium carbonate/bicarbonate or sodium hydroxide gradients. For example, a common mobile phase is ~1 mM NaHCO₃ / 3.5 mM Na₂CO₃ which was used to achieve the eight-anion separation. Hydroxide eluents (e.g. KOH or NaOH gradients from 1–30 mM) are also fully compatible and often yield even higher efficiencies with appropriate suppressors.
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pH Range
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0 – 14 stable. The column bed and binding chemistry tolerate any pH, so acidic eluent systems (less common, but used for certain organic acids perhaps) or alkaline washes are all allowed. No degradation or capacity loss across the pH spectrum under normal use.
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Organic Tolerance
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Compatible with up to 100% organic for cleaning. Typically, eluents remain aqueous (to maintain ionic strength and selectivity), but injecting samples containing organic solvents or using organic (e.g. acetonitrile) post-runs to clean the column is feasible. This aids in removing hydrophobic contaminants after, say, a sample with organics, preserving column performance.
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Operating Temperature
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15 – 40 °C recommended. Running at moderate temperature (e.g. 30 °C) can sometimes sharpen peaks or improve resolution slightly for some analytes (like separating acetate from fluoride), but even at ambient conditions the column performs excellently. High temperatures (above 40–50 °C) are usually not needed for anion IC but the column can withstand up to ~60 °C if required.
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Max Pressure
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~3000 psi typical operating, up to 5000 psi maximum. IonX-2 is packed for high efficiency, so backpressure will be modest (~1500 psi at 1 mL/min, 30 °C with standard carbonate eluent). It fits within the capabilities of all standard IC systems.
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Hardware
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PEEK construction, identical in outward design to IonX-300B, meaning it’s completely metal-free and inert. Comes with protective end plugs for storage. The column ships with a certificate of analysis and a sample chromatogram of a standard anion mix (including acetate) to verify performance.
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Guard Column
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Matching PEEK guard cartridges (CromSil IonX-2 Guard) are available (typically 50 mm length, packed with the same resin). Using the guard is recommended, especially for samples with unknown matrix components – it will capture irreversible adsorptives and extend the analytical column’s life. The guard is installed using a universal guard holder (PEEK) that connects directly in front of the main column.
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Specialized Selectivity for Acetate & More
IonX-2 is uniquely capable of separating organic acid anions (like acetate) from common inorganic anions in one method. This means analysts can avoid running two separate methods or using specialty organic acid columns – IonX-2 covers both, saving time and simplifying workflows when both types of anions are present.
High Resolution, High Efficiency
Despite its focus on selectivity, IonX-2 maintains excellent efficiency. Users achieve sharp, well-resolved peaks even for challenging pairs (e.g. fluoride vs. acetate, or bromide vs. nitrate) without sacrificing analysis time. The high plate count and optimized resin ensure resolution is achieved within standard run times (around 15 minutes for a full suite of anions).
Versatile & Robust
Like other CromSil IonX columns, IonX-2 is chemically robust (pH 0–14) and compatible with varied eluents and cleaning protocols. It can endure the same rigors of everyday lab use – strong acids/bases, organic washes, temperature variation – so you don’t need special treatment for this “specialty” column. It’s a drop-in replacement in any standard IC system using carbonate or hydroxide eluents.
Reproducible Performance
Each column is manufactured to tight specifications. The unique selectivity is reproducible from column to column, ensuring that when you develop a method on one IonX-2, you can replace the column months later and get the same retention pattern and selectivity. This lot-to-lot consistency is vital for validated methods and long-term projects.
Time-Saving Integration
For laboratories that frequently encounter samples containing both inorganic anions and small organic acids, IonX-2 consolidates analyses. For example, environmental labs testing groundwater might need chloride, sulfate, etc., but also acetic or formic acid from industrial contamination – now one column (one run) can do it. This increases throughput and reduces the need for multiple sample preps or multiple dedicated instruments.
Metal-Free, Low Bleed
The PEEK hardware and pure polymer packing mean the column itself doesn’t introduce any extraneous peaks or background. It exhibits low bleed, which is crucial for conductivity detection (no spurious conductivity from the column). And being metal-free, there’s no risk of metal leaching or catalyzing side reactions that could distort sensitive anion species (such as no metal-catalyzed degradation of perchlorate or similar).
Guard Kit for Longevity
The availability of a guard cartridge kit for IonX-2 allows users to protect the column’s unique selectivity for the long haul. Fouling or contamination can particularly affect the subtle selectivity balance; by using a guard, one ensures those potential fouling agents are caught early. The benefit is a consistently high-performing main column over a greater number of injections, which is cost-effective and reliable for critical analyses.
Broad Application Range
While specialized, IonX-2 isn’t limited to just acetate. Its design makes it a great general-purpose column for any situation where maximum resolution is needed. For instance, if regulatory limits get tighter and require better separation of a minor ion from a major neighbor, IonX-2 provides that extra resolving power. It’s an excellent “problem solver” column to have in the lab arsenal for tricky separations that standard columns can’t cleanly achieve.
Quality and Support
As part of the CromSil line, IonX-2 comes with full technical support. Application notes and example methods (including one demonstrating acetate separation) are available to help users get started quickly. The confidence in quality means it’s backed by warranty – if a column doesn’t meet performance specs, it will be replaced. This assurance underscores the reliability of IonX-2 for critical analytical work.
The CromSil™ IonX-1 column serves a broad range of application areas where accurate anion analysis is required. Its adaptability and reliability make it suitable for the following segments:
IonX-2 is particularly valuable in environmental labs dealing with natural waters or contaminated sites where organic acids and inorganic anions coexist. For instance, in analyzing landfill leachate or industrial wastewater, acetic acid (from degradation processes) might be present alongside chloride, nitrate, etc. IonX-2 can separate these components in one run, allowing accurate determination of both pollutant types. It’s also suitable for soil extract analyses, where acetate or formate could appear from soil organic matter – the column ensures those don’t interfere with important anions like nitrate (critical for nutrient studies) or sulfate.
Many foods and beverages contain organic acids (acetic, lactic, citric) as well as inorganic anions (chloride, phosphate). While IonX-2 is not designed for large polyprotic acids like citric, it handles small organics like acetate or formate well. In beverage quality testing (like wines, beers, kombucha), one might need to check for inorganic anions (from water or added salts) and organic acid content. IonX-2 could potentially allow a single IC run to quantify acetate alongside sulfate or chloride, providing a more efficient workflow for certain product analyses or fermentation monitoring.
In pharma, acetate is commonly used as a buffer or counterion (e.g., sodium acetate in formulations). When performing ionic impurity analysis, a standard anion column might co-elute acetate with other peaks or require a separate method. IonX-2 can resolve acetate distinctly, enabling QC labs to measure acetate and inorganic anions in drug products or injectable solutions in one go. Similarly, in biotech, culture media or bioprocess streams may contain acetate (as a byproduct or feed additive) along with chloride or phosphate – IonX-2 helps in monitoring those process streams comprehensively.
Employed in chemical manufacturing and plating industries to control anionic constituents in process streams, plating baths, or chemical products. For example, it can track sulfate or chloride levels in acids and bases, or monitor halides in chemical feedstocks, helping maintain product quality and process efficiency.
Researchers developing new IC methods or studying ion exchange phenomena might choose IonX-2 when the highest resolution is needed. For example, studies of disinfection by-products might look at small organic acids formed alongside inorganic oxyhalides – IonX-2 could help separate everything cleanly to allow individual analysis. Its unique retention characteristics also make it a subject of study for chromatography theory or for exploring how altering capacity impacts separation – educational labs might use it to demonstrate these concepts.
Some industries produce or use organic acid salts (like sodium acetate, sodium formate, etc.). IonX-2 is a fit for analyzing such products to ensure both the organic anion and any inorganic impurities are within spec. For example, a company manufacturing sodium acetate might use IonX-2 to check that their product is pure (acetate peak separated and quantified, and any chloride or sulfate impurity can be detected separate from the acetate). The column’s ability to separate acetate from common inorganic anions ensures confident monitoring of product purity.
Control Your Separations Like Never Before.
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