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01 02 03 04 DEFINITION Ion chromatography is a chromatographic technique used to separate and determine ions in a sample. Separation is based on the interaction between sample ions and an ion-exchange stationary phase. Commonly used for the analysis of inorganic anions and cations in environmental, pharmaceutical, food and forensic samples. Stationary Phase Mobile Phase Ion-Exchange Interaction Ions Separation Charged site attract and temporarily retain oppositely charged analyse ions. Separation based on reversible ion- exchange reactions between sample ions and stationary phase. Carries sample through chromatographic column. Ions are separated due to ion-exchange interaction differently with stationary phase. PRINCIPLE Christian et al., 2014 & Moura et al., 2022
06 Principle Of Ion Chromatogra phySeparation occurs through reversible ion-exchange reactions. Sample ions exchange with counter-ions attached to the stationary phase. Ion-exchange equilibrium occur. Example: R⁺Cl⁻ + NO₃⁻ ⇌ R⁺NO₃⁻ + Cl⁻ The strength of ion-exchange interactions determines the retention time of each ion. Stronger interactions produce longer retention times. Sample ions enter the column together with the mobile phase. Ions exhibit different affinities toward the stationary phase. Ions with weaker interactions elute faster. Ions with stronger interactions remain longer in the column. Different retention times allow ions to be separated and identified Consists of ion-exchange resin with fixed charged functional groups. Anion-exchange columns contain positively charged groups. Cation-exchange columns contain negatively charged groups. The stationary phase attracts and temporarily retains oppositely charged analyte ions. Different ions interact with the stationary phase to different extents. Stationary Phase Mobile Phase Ion Separation Ion Exchange Interaction The mobile phase (eluent) is a liquid containing competing ions that flows continuously through the column. It transports sample ions through the stationary phase. Eluent ions compete with analyte ions for the exchange sites. The composition and concentration of the mobile phase influence the separation efficiency and retention time. Christian et al., 2014 & Moura et al., 2022 & Michalski et.al, 2024
WORKING MECHANISM Pump continuously pushes the mobile phase through system at constant flow rate and high pressure. Pump 01 Sample introduction. Sample injected into flowing mobile phase. Injector 02 Movement through column and ion- exchange separation process. Column 03 Reduces the background conductivity of eluent to improve detection sensitivity. Supressor 04 Detection of ions. Commonly measure using conductivity detector as ionic species conduct electricity. Produces chromatographic peaks. Detector 05Boglárka Páll, Imre Kapui, Róbert Kormány & Krisztián Horváth. 2022. Development of Analytical Methods for the Determination of N-Bromosuccinimide in Different Active Pharmaceutical Ingredients by High-Performance Ion Chromatography with Suppressed Conductivity Detection. Separations 10(1): 15–15. https://doi.org/10.3390/separations10010015
Working Mechanism The sample solution containing dissolved ions is injected into the ion chromatograph using an injection valve or autosampler. The sample enters the flowing mobile phase (eluent), which carries the ions into the separation column. SAMPLE INTRODUCTION The mobile phase continuously flows through the column and transports the sample ions. The column contains an ion-exchange stationary phase with charged functional groups that interact with the analyte ions.MOVEMENT THROUGH COLUMN As the ions move through the column, they interact differently with the stationary phase depending on their charge, size, and affinity for the exchange sites. Ions with weaker interactions spend less time in the column and elute first, whereas ions with stronger interactions are retained longer and elute later. This difference in retention time results in the separation of ions.SEPARATION PROCESS After leaving the column, the separated ions pass through a detector. The detector measures changes in electrical conductivity caused by the ions. Each ion produces a characteristic peak at a specific retention time in the chromatogram.DETECTION OF IONS01020304 The five physical order of instructions of the flow path of ion chromatography can be explained in four general concept.
01 05 Detector SupressorInjector Contains the ion-exchange stationary phase. Separates ions according to their interactions with the charged sites on the resin. Produces different retention times for different ions. Delivers the mobile phase (eluent) at a constant flow rate and pressure. Ensures continuous movement of the sample through the system. Maintains stable operating conditions for reproducible separations. Pump Step Detects the ions based on changes in electrical conductivity. Produces chromatographic peaks. Retention time is used for identification. Peak area is used for quantification of ions. Step Reduces the background conductivity of the eluent. Converts the eluent into a less conductive form. Enhances the conductivity signal of analyte ions. Improves the sensitivity and accuracy of conductivity detection. Step 04 Ion-Exchange Column Step 03 Introduces a known volume of sample into the system. Mixes the sample with the mobile phase. Ensures accurate and reproducible sample injection. Step 02 INSTRUMENTATION OF ION CHROMATOGRAPHY An ion chromatography system consists of several important components that work together to separate and detect ions in a sample. Purpose: Delivers mobile phase Purpose: Introduce sample Purpose: Separate ions Purpose: Reduce background conductivity Purpose: Detect and quantifies ions
01 02 03 04 05 Ion chromatography can detect ions at very low concentrations, often at the ppm or ppb level. High Sensitivity Different ions can be effectively separated based on their ion- exchange interactions. Closely related ions can be analyzed simultaneously with good resolution. High Selectivity, Good Separation Several cations or anions can determined in single analysis. This reduces analysis time and increases laboratory efficiency. Simultaneous Analysis of Multiple Ions Ion chromatography provides rapid analysis with good precision and reproducibility. Automated systems minimize human error and improve reliability. Fast and Accurate Analysis Many aqueous samples require only filtration or dilution before analysis. This reduces sample handling and lowers the risk of contamination. Minimal Sample Preparation Advantages of Ion Chromatography Ion chromatography is widely used for the analysis of ionic compounds because it offers several advantages over conventional analytical techniques.
01 02 03 Application of Ion Chromatography in Water Quality Testing Groundwater Monitor water quality and environmental conditions. Detect ionic contaminants and pollutants. TYPE OF SAMPLE PURPOSE OF ANALYSIS Drinking water Ensure compliance with water quality regulations. Determine major inorganic ions. River water Ion chromatography allows simultaneous determination of these ions with high sensitivity and selectivity. COMMON IONS ANALYZED Mineral water Anions: Cl⁻, NO₃⁻, SO₄²⁻ Cations: Na⁺, NH₄⁺, K⁺, Mg²⁺, Ca²⁺ Ion chromatography is widely used in water quality testing because it allows the determination of various inorganic ions with high sensitivity and accuracy. It is commonly applied in environmental monitoring and drinking water analysis. Tap water Wastewater Acid rain water (Wu et al., 2021; Michalski & Kończyk, 2024)
01 02 03 Service Differentiation Price Differentiation Exceptional customer service should be a key positioning strategy. Position the brand to achieve premium value or optimal balance. Specific Example (Case Study) Suppressed conductivity detector (most common) UV detector (210 nm) Visible detector Fluorescence detector Detects separated ions after elution. Produces chromatographic peaks. Retention time identifies ions. Peak area determines ion concentration. Type of Detector Function of Detector Sample Type: Acid rain water Purpose: Determine Cl , NO , SO , Na , NH , K , Mg , Ca - 3- 42- + 4+ + 2+ 2+ Eluent used: 5 mM tartaric acid + 7.5% methanol-water Detector: Conductimetric detection Application of Ion Chromatography in Water Quality Testing (Tanaka et al., 1994)
Christian, G.D., Dasgupta, P.K. & Schug, K.A. 2014. Analytical chemistry. hlm. 692–700. Edisi ke-7. J. Wiley & Sons: Hoboken. Tanaka, K., Ohta, K., Fritz, J., Matsushita, S., & Miyanaga, A. (1994). Simultaneous ion-exclusion chromatography- cation-exchange chromatography with conductimetric detection of anions and cations in acid rain waters. Journal of Chromatography A, 671, 239-248. https://doi.org/10.1016/0021-9673(94)80245-9 Michalski, R. & Kończyk, J. 2024. Ion Chromatography and Related Techniques in Carbohydrate Analysis: A Review. Molecules 29(14): 3413–3413. https://doi.org/10.3390/molecules29143413 Varão Moura, A., Da Silva, J.D.S. & Gubert, P. 2022. Ion Chromatography: Principles and instrumentation. Orbital: The Electronic Journal of Chemistry 14(2): 110–115. https://doi.org/10.17807/orbital.v14i2.15871 Wu, D., Hu, Y., Liu, Y. & Zhang, R. 2021. Review of Chloride Ion Detection Technology in Water. Applied Sciences 11(23): 11137. https://doi.rog/ 10.3390/app112311137 Boglárka Páll, Imre Kapui, Róbert Kormány & Krisztián Horváth. 2022. Development of Analytical Methods for the Determination of N- Bromosuccinimide in Different Active Pharmaceutical Ingredients by High-Performance Ion Chromatography with Suppressed Conductivity Detection. Separations 10(1): 15–15. https:..doi.org.https://doi.org/10.3390/separations10010015 REFERENCES