Ion Chromatography

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Electrolytic Suppression and Ion Chromatography

The conductivity detector 's response is saturated when the mobile phase has an intensive conductivity , thus , ion suppression is employed (Levin . In doing this , a suppressor is added into the system between the detector and the column . Depending on the properties of the mobile phase , the suppressor produces hydroxyl or hydronium ions to transform their corresponding ions into non-ionized state resulting to reduced conductivity (Levin . While the conductivity of the mobile phases is lessened , the conductance of the

solute is improved that enhances detection (Levin . For continuous operation , the suppressor contains scavenger or regenerant (Levin . For an acidic mobile phase , the suppression is done through the cation-exchange column in the hydrogen form . For instance , the elution of the Chloride solutes by Sodium bicarbonate mobile phase can be described by the following equations (Levin

Resin-H Na HCO32- Resin-Na H2CO3 (eluent

Resin-H Na Cl- Resin-Na HCl (solute

A similar process is applied to cation-exchange chromatography where the anion-exchange column is the suppressor in hydroxyl form (Levin . For example , the separation of sodium ions by means of HCl mobile phase is possible by transforming eluent into water as the conductivity of the solute is improved . This can be shown by the following equations (Levin

Resin-OH- H Cl- Resin-Cl- H2 O (eluent

Resin-OH- Na Cl- Resin-Cl- Na OH- (solute

Conductivity Detector

Conductivity detection works best for inorganic ions since they are naturally electrical conductors , thus , the detector has a universal response (Levin . Also , detectors...