If you are trying to analyze organic acids and alcohols in complex or high-ionic-strength samples, you should consider the Anion MicroMembrane Suppressor for ICE (AMMS^® -ICE 300). This suppressor is ideally suited to ion-exclusion chromatography of organic acids and alcohols in complex or high-ionic-strength samples.

AMMS-ICE 300 Advantages

• High-capacity and solvent compatible design optimized for organic acid and alcohol analysis in complex or high-ionic-strength samples.
• Low method detection limits as a result of very low signal-to-noise and excellent baseline stability
• Fast start-up and equilibration

Increased Sensitivity with Suppressed Conductivity Detection

The AMMS-ICE 300 suppressor is used in the chemical suppression mode with a tetrabutylammonium hydroxide (TBAOH) regenerant. The ICE suppression mode is based on a mechanism that is a reversal of that traditionally seen in the suppression of acidic eluents. In the ICE system, the eluent is an acid, while the analytes are anionic. As shown in the figure below, the AMMS-ICE 300 removes the hydronium ion present in the eluent and any other counterions of the analytes from the eluent stream and replaces them with tetrabutylammonium ion (TBA⁺). Since the hydronium ion is the main source of conductance, this removal greatly reduces the background conductivity of the system. In addition, this mechanism forces the ionization of the weak acid analytes, greatly increasing sensitivity.

Optimized for Ion-Exclusion Chromatography and Ion-Suppression Chromatography

The AMMS-ICE 300 has been improved to allow use at temperatures up to 40 ºC with eluents containing HPLC solvents. Elevated temperatures or solvents can be used to increase peak efficiency or alter column selectivity in ion-exclusion and ion-suppression separations. The suppressor can be placed inside a chromatography oven for operation at elevated temperature. The AMMS-ICE 300 is designed for use with either the ion-exclusion or ion-suppression separation modes of ion chromatography. Both modes use dilute eluents containing acids with low pK_a values. Ion-exclusion uses a cation-exchange phase, typically in the hydronium form, to selectively exclude weak acids on the basis of differences in pK_a. In contrast, ion-suppression chromatography uses an acidic eluent that suppresses ionization of analytes, thus allowing the separation of weak acids using a hydrophobic reversed-phase column such as the IonPac NS1.

AMMS-ICE 300 Applications

The AMMS-ICE 300 is ideally suited to the ion-exclusion chromatography of:

• Organic acids and alcohols in complex or high-ionic-strength samples, including food and beverage products, biological samples, fermentation processes, industrial process liquors, and treated wastewaters
• Organic acids in high-ionic-strength matrices
• Other weak acids, such as fatty acids