Detection methods in ion chromatography: a comprehensive overview

28. 9. 2026

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Ion chromatography (IC) is a powerful analytical technique used to separate and quantify ionic species in various sample matrices. Detection method choice depends on the analyte(s) of interest and is crucial to achieve high sensitivity and selectivity. This article explores the fundamental principles of key detection techniques in IC, including non-suppressed and suppressed conductivity detection, UV/VIS detection, amperometric detection, and hyphenated techniques like mass spectrometry (MS) and inductively coupled plasma mass spectrometry (ICP-MS). Understanding these techniques helps IC users select the most appropriate detection system for specific applications.

This article covers the following topics:

Which detection methods are used in ion chromatography?
Conductivity detection
Conductivity detection with suppression
UV/VIS detection
Amperometric detection
Hyphenated techniques
When do you use which detection method?

Which detection methods are used in ion chromatography?

Ion chromatography relies on many detection methods to efficiently identify and quantify analytes. The most commonly used detection techniques include ([1–6]):

Conductivity detection: The most universal and widely used detection method in IC, suitable for analytes such as anions, organic acids, cations, or amines. To achieve higher sensitivity, conductivity detection is often combined with suppression to reduce the background conductivity from the mobile phase (eluent).
UV/VIS detection: Ideal for analytes with chromophores that absorb ultraviolet or visible light, such as nitrite or nitrate. For non-absorbing analytes, either pre- or post-column derivatization can be used.
Amperometric detection: Best suited for electroactive compounds like carbohydrates and phenols.
Hyphenated techniques (ESI-MS, ESI-MS/MS, and ICP-MS): These methods provide enhanced specificity and sensitivity, particularly for trace-level analysis and elemental speciation.

Each technique offers distinct advantages and limitations, which are explored in detail in the following sections.

Conductivity detection

Conductivity detection measures the change in electrical conductivity as ions pass through the detector. When an analyte elutes from the separation column, it alters the conductivity of the mobile phase, producing a measurable signal [7].

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The eluent—the mobile phase which carries the sample and its ions—flows through a separation column in the ion chromatography system.
In the separation column, the analytes are separated (anion or cation exchange) and enter time-resolved into the conductivity cell. The conductivity cell contains two electrodes with a low voltage applied across them.
The presence of ions in the eluent influences the cell conductivity. Ions enhance the electrical conductivity of the eluent, causing changes to the electrical current flowing through the cell.
The changes in electrical conductivity are converted into electrical signals. These signals are typically amplified and sent to a data acquisition system for further processing and analysis.
The detector response is calibrated using known standards to establish a relationship between the signal generated and the concentration of the analyte ions. This calibration allows for the quantification of the analyte ions in the sample.

Limitations and challenges of conductivity detection:

Poor sensitivity for weakly ionized species
Background conductivity from the eluent can interfere with measurements (mitigated by suppression)
Less suitable for organic or complex matrix samples with low conductivity

OMNIS IC S COND/MSM/PP/CH

2.1050.0020

The OMNIS IC S COND/MSM/PP/CH is the start instrument in the OMNIS IC world with basic sample introduction and chemical suppression. It is provided as a pre-installed, ready-to-use sales version with an OMNIS High-Pressure Pump Unit, an OMNIS Actuator Unit, an OMNIS Conductivity Detector Unit, an OMNIS MSM Unit, and an OMNIS Peristaltic Pump Unit with two channels. It features a transparent door for easy access and a Reagent Organizer.It is equipped with an OMNIS Column Holder Unit with intelligent column chip technology. For sample transport and injection, a peristaltic pump and a 6/2-port valve are integrated. The 3 empty unit spaces give flexibility to upgrade the system, for example, with an OMNIS Dosing Drive Unit, an OMNIS MISP Unit, an OMNIS Degasser Unit, or an OMNIS MCS Unit for sequential suppression.The OMNIS IC instrument is foreseen to be placed on an autosampler. There is the free choice to add an integrated OMNIS IC Autosampler or an OMNIS IC Autosampler COOL for full automation; alternatively, it can be placed on a baseplate, for example, in case of a double tower solution.The OMNIS IC S COND/MSM/PP/CH can be used for applications with chemical suppression. At any time, OMNIS Extension Modules can be added to upgrade the OMNIS IC S system, for example, to improve performance with sequential suppression or Metrohm Inline Sample Preparation options.The OMNIS IC instrument is compatible with the 947 Professional UV/VIS Detector Vario, and the 945 Professional Detector Vario – Amperometry, expanding the options for detection.The OMNIS IC S COND/MSM/PP/CH is an ideal choice for applications like standard anions in simple matrices such as surface or drinking water.

OMNIS IC Autosampler Module

2.1054.0010

The OMNIS IC Autosampler automates the sample change in the OMNIS IC System and enables efficient processing of up to 160 vials of 5 mL each, depending on the selected rack. As the first fully integrated autosampler of the new OMNIS IC generation, it is installed directly below the OMNIS IC as standard. It is not a stand-alone device, but an integral part of the OMNIS IC System, which is conveniently controlled via the OMNIS Software.Key features:Compact footprint: Can be placed directly under the OMNIS IC; High sample throughput: 96 x 10 mL vials, 160 x 5 mL vials, 192 x (1500, 700, 300) µL HPLC vials, 384 x 2 mL well format (deep well plate); High speed (30 s/injection of 5 µL); Removable autosampler tray for easy loading and unloading; Interior lighting for easy loading and unloading; Fast and precise xyz needle drive with automatic vial detection; Follow-up light and status display for visual traceability of needle movement and autosampler status; High flexibility for different sample vessels and rack types (including customer-specific racks); Six integrated positions for 50 mL bottles, e.g., for standards or rinsing solutions; Integrated rinsing station and leak detection as standard for maximum safety; Fully integrated into the OMNIS Software; Optional upgrades: 3/2-way valves, dilution station, barcode reader;

Metrosep C 6 - 250/4.0

6.1051.430

The Metrosep C 6 - 250/4.0 is the cation column with the greatest capacity in the C 6 series. It is predestined for applications which require the highest separating efficiency. Samples with extreme differences in concentrations can be analyzed reliably with this column. The separation of sodium and ammonium is particularly outstanding here.

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Conductivity detection with suppression

By using so-called «suppression» techniques, the inherent conductivity of certain eluents can be dramatically reduced and the sensitivity considerably improved [7].

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Chemical suppression in ion chromatography increases sensitivity by reducing the background conductivity, making it easier to detect ionic analytes at low concentration. This is done by converting the eluent to a weakly conductive form after analyte separation. The mechanism depends on whether anions or cations are analyzed [1].

Click on each header below to expand for more information.

Figure 1. Reactions taking place in the Metrohm Suppression Module (MSM Rotor A) when performing suppressed anion chromatography [1].

The suppressor replaces high-conductivity eluent cations (e.g., Na⁺ from sodium carbonate or sodium bicarbonate) with weakly dissociating acids. This results in a much lower background conductivity [1].

Figure 1 shows an example of a sodium bicarbonate eluent. Here, sodium is replaced by H⁺, forming carbonic acid—a weak acid with very low conductivity that dissociates only slightly into CO₂ and H₂O. This leads to a stable background conductivity (~15 µS/cm), ideal for most analyses.

When a sample anion such as chloride (Cl^-) is injected, it undergoes a similar reaction (Figure 1). The result is a strong acid with much higher conductivity, producing a sharp signal.

For anions, the reactions mentioned above can be used to determine the following sensitivities for conductivity detection (Table 1).

**Table 1.** Sensitivity for anions without and with suppression (Λ = equivalent conductivity (S cm² mol^-1)) [1].
Anion	Sensitivity without chemical suppression (Λ-_sample) – (Λ-_phthalate)	Sensitivity with chemical suppression (Λ-_sample) – (Λ+_H)
Fluoride	16	404
Chloride	38	426
Nitrate	33	421
½ Sulfate	42	430
Acetate	3	391

According to Table 1, the sensitivity for anions is approximately 10 times higher with suppression than without it.

Figure 2. Cation suppression for analytes and eluent with carbonate/bicarbonate.

Cation suppression is often used when strong acids (e.g., nitric acid) serve as eluents. The acids are converted into carbonic acid (H₂CO₃), and when using sequential suppression through an anion exchange post-column reaction, they are converted even further to CO₂ and H₂O (Figure 2) [1]. The result is very low residual conductivity.

**Table 2.** Sensitivity for cations without and with suppression (Λ = equivalent conductivity (S cm² mol^-1)) [1].
Cation	Sensitivity without chemical suppression (Λ-_sample) – (Λ+_H)	Sensitivity with chemical suppression (Λ-_sample) – (Λ-_OH)
Lithium	-311	237
Sodium	-300	248
Potassium	-276	272
Ammonium	-277	271
½ Magnesium	-397	251
½ Calcium	-290	258

By combining chemical suppression with an additional CO₂ suppression step (e.g., MCS, or Metrohm Carbonate Suppression), detection sensitivity and baseline stability increase even more [1].

After chemical suppression (for anions or cations), this method removes dissolved CO₂ by applying a vacuum to the eluent after the chemical suppression step. This shifts the carbonate equilibrium towards carbonic acid, CO₂, and water (Figure 3) [1].

Figure 3. Reaction that takes place in the MCS.

As a result, the background conductivity in anion analysis drops to below 1 µS/cm—comparable to ultrapure water. This significantly reduces the water dip and carbonate system peak, which often interfere with early-eluting analytes. Figure 4 shows that peaks previously affected by these baseline disturbances now appear cleaner and more resolved.

Chromatogram of standard anions along with chemical suppression (MSM, blue) and a chromatogram of the same standard applying sequential suppression (MSM + MCS, red). The water dip (1, injection peak) and the system peak (2, carbonate peak) are no longer present with sequential suppression.

Figure 4. Chromatogram of standard anions along with chemical suppression (MSM, blue) and a chromatogram of the same standard applying sequential suppression (MSM + MCS, red). The water dip (1, injection peak) and the system peak (2, carbonate peak) are no longer present with sequential suppression.

Suppressors used in ion chromatography can be configured in two ways: as discontinuously operating packed-bed suppressors or as continuously operating membrane suppressors [6,7]. Both are discussed in this section.

The packed-bed suppressor designed by Metrohm employs a revolver system that contains three identical suppressor chambers—each filled with ion-exchange resin. One chamber functions as the suppressor while the second is regenerated, and the third is rinsed with the effluent from the detector («STREAM», i.e., the eluent is used for rinsing the regenerated MSM after exiting the detector). After completing an analysis, the revolver is rotated by 120°, allowing the freshly rinsed chamber to take over as the acting suppressor. This design enables nearly continuous operation [7].

Membrane suppressors (Figure 5) enable continuous operation. However, due to the use of ion exchange membranes, the membrane surface can become occupied or overloaded. This reduces the suppressor's effectiveness and eventually leads to its failure to function properly.

Figure 5. Schematic illustration of a continuously working membrane suppressor for analytes with sodium hydroxide eluent. Figure modified from [6].

UV/VIS detection

UV/VIS detection relies on the absorption of ultraviolet (UV) or visible (VIS) light by analytes. This detection method is useful for compounds containing chromophores, such as aromatic compounds and transition metal complexes. Pre- or post-column derivatization techniques can enhance the detection of non-absorbing analytes [5,7].

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The UV/VIS detector consists of a light source that emits a broad spectrum of light, including ultraviolet and visible wavelengths.
The sample, dissolved in an appropriate solvent, is injected into the chromatography system and carried through a flow cell.
As the sample passes through the flow cell, it interacts with the light beam emitted by the light source. Some of the wavelengths of light are absorbed by the compounds present in the sample.
The UV/VIS detector measures the amount of light that passes through the sample (transmittance) rather than being absorbed. It does this by comparing the intensity of the light beam before the measurement (baseline spectrum, autozero) with the intensity after it passes through the sample.
The UV/VIS detector generates an electrical signal proportional to the amount of light transmitted through the sample. This signal is typically converted into a numerical value or a chromatogram peak, indicating the absorbance of various resolved analytes in the sample at specific wavelengths.
The detector response is calibrated using known standards with known concentrations of compounds. This calibration curve establishes a relationship between the absorbance and the concentration of the analyte of interest. By comparing the absorbance of the sample with the calibration curve, the concentration of the analyte in the sample can be determined.

Limitations and challenges for UV/VIS detection:

Requires analytes to have UV or visible absorbance
May require derivatization for certain non-absorbing compounds
Less universal than conductivity detection

OMNIS IC M Module

2.1051.0010

The OMNIS IC M Module is a high-class single-channel instrument in the OMNIS IC world and gives the entire flexibility for complete customization. It includes an OMNIS High-Pressure Pump Unit, an OMNIS Actuator Unit with a flexible choice of the injection valve, an OMNIS MISP Unit, and an OMNIS Column Thermostat Unit 1 (one channel, upgradeable), and features a transparent door for easy access.The OMNIS MISP Unit offers complete flexibility to add the Metrohm Inline Sample Preparation (MISP) options, which perfectly suit the application needs, such as Ultrafiltration, Metrohm intelligent Partial Loop Injection Technique (MiPT), or can be used as a holder for a trap column. The MISP techniques improve efficiency and accuracy while reducing the number of manual steps typically involved in sample preparation.The built-in Multi Flow Monitor Unit enables smart flow monitoring for up to four channels. It detects flow trend variations, for example, induced by worn tubings or fouled filtration membranes, and can trigger software actions to minimize disturbances.The additional 8 free units enable the creation of a fully personalized IC system. Tailored to meet the individual application needs, the OMNIS IC M Module can be equipped with various units, such as the OMNIS Conductivity Detector Unit, the OMNIS MSM Unit, the OMNIS MCS Unit, the OMNIS Degasser Unit, the OMNIS Peristaltic Pump Unit, or even with automatic eluent production, low-pressure gradient, or dual-column use.Blind Cover Units are standard not provided and need to be added additionally.A baseplate or autosampler is required, along with a Reagent Organizer or Reagent Organizer Liquid Control. For full automation, there is the free choice to add an integrated OMNIS IC Autosampler or an OMNIS IC Autosampler COOL.At any time, the OMNIS IC M Module can be upgraded with freely configurable OMNIS Extension Modules, to further improve the performance.The OMNIS IC instrument is compatible with the 947 Professional UV/VIS Detector Vario, and the 945 Professional Detector Vario – Amperometry, expanding the options for detection.Reach out to your local IC specialist to configure your own fully customized ion chromatograph tailored to your specific application needs.

OMNIS IC Autosampler Module

2.1054.0010

947 Professional UV/VIS Detector Vario SW

2.947.0010

As an intelligent, single-wavelength detector, the 947 Professional UV/VIS Detector Vario SW permits a secure and reliable quantification of substances active in the ultraviolet or visible range. One wavelength can be selected.

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Amperometric detection

Amperometric detection uses an electrochemical cell to measure the current generated by the oxidation or reduction of analytes at the electrode surface [1,5,6]. It is highly selective for electroactive compounds, including carbohydrates, sugar alcohols, and certain anions/cations.

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The amperometric detector consists of an electrochemical cell containing two electrodes: a working electrode (WE) and a reference electrode (RE).
As the analyte compounds elute from the separation column, they reach the electrochemical cell. Depending on their nature, they undergo either oxidation or reduction reactions at the surface of the WE (oxidation reactions are most common).
During the oxidation or reduction reaction, electrons are either gained or lost by the analyte compounds. This electron transfer generates an electrical current proportional to the concentration of the analyte.
The electrical current produced by the oxidation or reduction reaction is measured by the amperometric detector. The current is typically amplified and converted into a detectable signal.
To determine the concentration of the analyte compounds, the amperometric detector response is calibrated using known standards with known analyte concentrations. This calibration allows for the quantification of the analyte compounds in the sample.

Limitations and challenges of amperometric detection:

Requires careful electrode maintenance and conditioning
Sensitivity can be influenced by matrix effects and electrode fouling
Limited to analytes that undergo electrochemical reactions

OMNIS IC M COND/MSM/MCS/PP/DEG/DD/ROLC

2.1051.0020

The OMNIS IC M COND/MSM/MCS/PP/DEG/ DD/ROLC is the high-class single channel instrument in the OMNIS IC world. It is provided as a pre-installed, ready-to-use sales version with an OMNIS High-Pressure Pump Unit, an OMNIS Actuator Unit, an OMNIS Conductivity Detector Unit, an OMNIS MSM Unit, an OMNIS MCS Unit, an OMNIS Degasser Unit, an OMNIS Peristaltic Pump Unit with one channel, and OMNIS Dosing Drive Unit. It features a transparent door for easy access and a Reagent Organizer Liquid Control.The integrated OMNIS Column Thermostat Unit 1 features a removable column tray with intelligent column chip technology and regulates the column temperature (5–80 °C, depending on ambient temperature). The column thermostat is intended for single-column use, but can be upgraded to support two columns at any time. For sample transport and injection, a peristaltic pump and a 7/3-port valve are integrated.For high-throughput applications, the OMNIS IC M COND/MSM/MCS/PP/DEG/DD/ROLC comes with an OMNIS MISP Unit for integrated sample preparation. The OMNIS MISP Unit provides complete flexibility to add Metrohm Inline Sample Preparation (MISP) options, perfectly tailored to the application needs, such as Ultrafiltration, Metrohm intelligent Partial Loop Injection Technique (MiPT), or can be used as a holder for a trap column. These MISP techniques enhance efficiency and accuracy while reducing the manual steps usually involved in sample preparation.The built-in Multi Flow Monitor Unit enables smart flow monitoring for up to four channels. It detects flow trend variations, for example, induced by worn tubing or fouled filtration membranes, and can trigger software actions to minimize disturbances.The included Reagent Organizer Liquid Control functions not only as a holder for liquids and eluent bottles but also has an integrated light that illuminates the instrument's interior when at least one door is open. The integrated leak and level sensors are monitored by the OMNIS software and support automatic eluent production and liquid level control.The OMNIS IC instrument is foreseen to be placed on an autosampler. There is the free choice to add an integrated OMNIS IC Autosampler or an OMNIS IC Autosampler COOL for full automation; alternatively, it can be placed on a baseplate, for example, in case of a double tower solution.The OMNIS IC instrument is compatible with the 947 Professional UV/VIS Detector Vario and the 945 Professional Detector Vario – Amperometry, expanding the options for detection.The OMNIS IC M COND/MSM/MCS/PP/DEG/DD/ROLC serves as a flexible, high-throughput single-channel device. Additional upgradeability with OMNIS Extension Modules broadens its capabilities to meet future demands, such as dual-channel ion chromatography or extended liquid handling functions.The high-class OMNIS IC M instrument is the ideal choice for qualified or sophisticated applications requiring sequential suppression and temperature-controlled column conditions, such as oxyhalide analyses or suppressed cations analyses in various matrices. Due to integrated sample preparation, even complex matrices can be handled, while manual workload is minimized and accuracy is increased.

OMNIS IC Autosampler Module

2.1054.0010

945 Professional Detector Vario – Amperometry

2.945.0020

Intelligent stand-alone detector equipped with the IC Amperometric Detector. Outstanding selectivity due to the four measuring modes: DC, PAD, flexIPAD, CV. The excellent signal/noise ratio and the very fast start-up guarantee the highest in measurement precision. For use with intelligent IC instruments or as independent detector.

Metrosep Carb 2 - 250/2.0

6.01090.230

The Metrosep Carb 2 - 250/2.0 IC column is particularly suitable for the determination of carbohydrates using alkaline eluents and pulsed amperometric detection. The high-capacity anion exchanger column is based on a styrene-divinylbenzene copolymer. It is stable in the range of pH = 0 - 14 and separates monosaccharides and disaccharides. It is also suitable for the analysis of sugar alcohols, anhydrous sugars, amino sugars, etc. The 250 mm Microbore version of the Metrosep Carb 2 separation column is optimized for complex separations.Thanks to its low eluent consumption, it is particularly suitable for IC-MS coupling.

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Hyphenated techniques:
Mass Spectrometry (MS) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS)

Mass spectrometers, such as those used for ESI (electrospray ionization)-MS, ESI-MS/MS, and ICP-MS, detect analytes based on their mass-to-charge ratio, offering high sensitivity and specificity [6]. These techniques are particularly useful for trace-level detection, elemental speciation, and confirming the identity of complex analytes.

The inert instrumentation used in ion chromatography allows for mobile phase flexibility and helps protect the detector against contamination—crucial for trace elemental speciation. The ion chromatography suppression techniques ensure that only analytes and water (along with some organic modifiers, if necessary) enter these highly sensitive mass spectrometers. This is advantageous for maintaining stable operating conditions, enhancing analysis sensitivity, and extending the instrument's lifespan.

Limitations and challenges of hyphenated techniques:

Requires sophisticated instrumentation and expertise
Higher operational costs compared to other detection methods
Sample preparation may be necessary to eliminate matrix interferences

When do you use which detection method?

Selecting the appropriate detection method depends on the application and analyte properties. The following table summarizes the different detectors used in ion chromatography and the applications they excel at.

Detection method	Applications	Key benefits
Conductivity	Anions, cations, amines	Universal, maintenance-free, nondestructive
UV/VIS	Bromate, chromate, oxo-compounds, nitrogen/sulfur compounds, halogens, organic substances	High specificity, flexible wavelength settings
Amperometry	Carbohydrates, sugar alcohols, electroactive organic substances	High selectivity and sensitivity for redox-active compounds
Mass spectrometry (ESI-MS, ESI-MS/MS, ICP-MS)	Trace elements (Cr, As, Se, I, Fe, etc.) (ICP-MS), pesticides, amines, haloacetic acids, organic molecules (ESI-MS, ESI-MS/MS)	Ultra-high sensitivity, peak identification

Examples are given in the following sections. Click each header to expand for more information.

Analyte	Separation Column	Application Note
F^-, ClO₂^-, BrO₃^-, Cl^-, NO₂^-, Br^-, ClO₃^-, NO₃^-, DCA, SO₄^2-, PO₄^3-	Metrosep A Supp 21	Water quality testing with EPA 300.1
BrO₃^-	Metrosep A Supp 17	Analysis of bromate in drinking water according to ISO 11206 and EPA 317
PFAS (monitoring)	Metrosep A Supp 5 - 250/4.0	Monitoring PFASs in water sources
Cl^-, PO₄^3-, NO₃^-, SO₄^2-	Metrosep A Supp 10	Anions and cations in beer
Na⁺, K⁺, Ca²⁺, Mg²⁺ (unsuppressed)	Metrosep C 6	Anions and cations in beer
F^-	Metrosep A Supp 16	Fluoride in sodium fluoride tablets for pharmaceutical use
Citrate, phosphate	Metrosep A Supp 3	Assay for citric acid/citrate and phosphate according to USP <345>
Gluconate, lactate, acetate, propionate, isobutyrate, butyrate, methacrylate, valerate, methyl sulfate, dichloroacetate, malonate, malate, glutarate, adipate, phthalate	Metrosep A Supp 7	Assessing wine quality with IC

Analyte	Separation Column	Application Note
NO₃^-, NO₂^-	Metrosep A Supp 7 Metrosep A Supp 5	Nitrite and nitrate in meat products
NO₂^-	Column: Metrosep A Supp 10 - 250/4.0 Pre-concentration: Metrosep A PCC 2 HC/4.0	Nitrite in hydroxypropyl methylcellulose
Br-, NO₂^-, NO₃^-	Metrosep A Supp 7	Anions in high ionic water by IC using tandem conductivity and UV detection
Melamine	Metrosep C 4	Melamine in food using cation chromatography with UV/VIS detection
BrO₃^- (PCR)	Metrosep A Supp 10	Analysis of bromate in drinking water according to ISO 11206 and EPA 317
CrO₄^2-	Metrosep A Supp 17	Chromate (Cr(VI)) in water
Silica (PCR)	Metrosep A Supp 7	Silicate in cooling agents
Cu, Zn, Fe (PCR)	Metrosep C 2	Copper, zinc, iron(II), and manganese in wine by ion chromatography with post-column reaction and UV/VIS detection
Zn (PCR)	Metrosep A Supp 10	Zinc Oxide Assay as per USP General Chapter <591>
EDTA, HEDTA, and DTPA	Metrosep A Supp 3	Determination of EDTA, HEDTA and DTPA according to EN 13368-1
Tolyltriazole, benzotriazole, and 2-mercaptobenzothiazole	MetroSil RP 3	Online monitoring of copper corrosion inhibitors in cooling water

Analyte	Separation Column	Application Note
I^-	Metrosep A Supp 17	Iodine monitoring in natural sources
CN^-, S^2-	Metrosep A Supp 10	Cyanide and sulfide on Metrosep A Supp 10 - 100/2.0 using amperometric detection
Sulfites	Metrosep Carb 2 - 150/4.0	Simplified sulfite determination in foods and beverages using ion chromatography
Lactose	Metrosep Carb 2	Lactose intolerance and reliance on accurate food labels
Glucose, maltose	Metrosep Carb 2	Glucose and maltose derivatives separated on a Metrosep Carb 2 column applying a flow gradient
Inositol, glucose, fructose, and sucrose	Metrosep Carb 2	Carbohydrates in orange juice applying pulsed amperometric detection
Inositol, arabinol, sorbitol, glucose, xylose, fructose, lactose, sucrose, maltose	Metrosep Carb 2	Sugar and sugar alcohols in an apple beverage with pulsed amperometric detection
Mannitol, arabinose, galactose, mannose, xylose	Metrosep Carb 2	Quality assurance of instant coffee
Glyphosate, AMPA	Metrosep Carb 2	Glyphosate and AMPA in drinking water
Phenols	Metrosil RP 3	Four phenols in tap water using amperometric detection
Gentamicin	Phenomenex	Content of gentamicin according to USP applying pulsed amperometric detection

Analyte	Separation Column	Application Note
MCAA, MBAA, BrO₃^-, DCAA, Dalapon, BCAA, DBAA, TCAA, BDCAA, CDBAA, TBAA	Metrosep A Supp 19	Trace haloacetic acids, dalapon, and bromate measurement in drinking water
Trifluoroacetic acid	Metrosep A Supp 17	IC-MS/MS analysis of trifluoroacetic acid according to DIN 38407-53
ClO₄^-	Metrosep A Supp 7	Trace perchlorate in drinking water – Determination as per US EPA 332.0 applying IC-MS/MS
Br^-, BrO₃^-	Metrosep A Supp 5	Traces of bromide and bromate in drinking water by IC-MS, determination of the Method Detection Limit (MDL)
Urea	Metrosep C 6	Determination of urea in ultrapure water using IC-MS
Diethylamine, trimethylamine	Metrosep C 2	Traces of diethylamine and triethylamine by IC MS
Cetic, propionic, butyric, valeric, and caproic acid	Metrosep Organic Acids	Aliphatic monocarboxylic acids in produced water using IC/MS coupling
Iodate, iodide, iomeprol	Phenomenex Envirosep-PP	IC-ICP-MS analysis of iodized X-ray contrast media
Cr(III), Cr(VI) (as CrO₄^2-)	Metrosep Carb 2	Chromium speciation by IC-ICP-MS

Conclusion

Selecting the appropriate detection method in ion chromatography is crucial for the most accurate and reliable analysis. Conductivity detection remains the gold standard for general ionic species, while UV/VIS and amperometric detection offer enhanced selectivity for specific compounds. Hyphenated techniques like ESI-MS, ESI-MS/MS, and ICP-MS offer exceptional sensitivity and specificity for trace-level and complex analytes.

By understanding the principles and limitations of various detection methods, the best choice can be made for each individual application to ensure optimal performance.

References

[1] Schäfer, H.; Läubli, M. Monograph Ion Chromatography; Metrohm AG: Herisau, Switzerland, 2023. https://www.metrohm.com/en/products/8/1085/81085077.html

[2] Haddad, P. R.; Jackson, P. E. Ion Chromatography; Journal of Chromatography Library; Elsevier: Amsterdam, 1990. eBook ISBN: 9780080858531

[3] Michalski, R. Principles and Applications of Ion Chromatography. In Application of IC-MS and IC-ICP-MS in Environmental Research; John Wiley & Sons, Ltd, 2016; pp 1–46. DOI:10.1002/9781119085362.ch1

[4] Michalski, R. Ion Chromatography as a Reference Method for Determination of Inorganic Ions in Water and Wastewater. Critical Reviews in Analytical Chemistry 2006, 36 (2), 107–127. DOI:10.1080/10408340600713678

[5] Buchberger, W. W. Detection Techniques in Ion Chromatography of Inorganic Ions. TrAC Trends in Analytical Chemistry 2001, 20 (6), 296–303. DOI:10.1016/S0165-9936(01)00068-1

[6] Paull, B.; Nesterenko, P. N. Chapter 8 - Ion Chromatography. In Liquid Chromatography; Fanali, S., Haddad, P. R., Poole, C. F., Schoenmakers, P., Lloyd, D., Eds.; Elsevier: Amsterdam, 2013; pp 157–191. DOI:10.1016/B978-0-12-415807-8.00008-0

[7] Kolb, M.; Seubert, A.; Schäfer, H.; Läubli, M. (Editor). Monograph: Practical Ion Chromatography, 3rd ed.; Metrohm AG: Herisau, Switzerland, 2020. https://www.metrohm.com/en/products/8/1085/81085069.html

Additional resources

Brochure: Suppression in anion chromatography – More sensitive analysis of anions and organic acids

Brochure: Cation suppression in ion chromatography – Cation determination in the trace range

Monograph: Advanced Detection Techniques in Ion Chromatography

Monograph: Practical Ion Chromatography – An Introduction

White Paper: Coupling of ion chromatography and plasma mass spectrometry

White Paper: An introduction to ion chromatography mass spectrometry (IC-MS)

White Paper: Measuring organic acids and inorganic anions with ion chromatography mass spectrometry

On-demand webinar: An introduction to ion chromatography: Principles and applications

On-demand webinar: Redefining anion analysis with a new generation of separation columns

On-demand webinar: QC of infant food: Robust and efficient analysis of nutrients, additives, and contaminants

On-demand webinar: Optimize ion chromatography for your application

Monograph: Ion Chromatography

The fully revised and updated second edition of the monograph «Ion Chromatography» provides an in-depth exploration of the theory and practical applications of ion chromatography. Additionally, detailed discussions on the theory, detection methods, and separation column types are included. Download the monograph to learn more about ion chromatography.

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