The AutoNeutralization technique is an example of 2-D ion chromatography applied to perform an inline neutralization step on a concentrated acid or base sample. This replaces cumbersome manual dilution and neutralization procedures prior to injection. While this works to reduce the concentration of the interfering matrix ion(s) to a level that does not affect separation dilution also reduces the concentration of trace ions and consequently compromises detection. AutoNeutralization solves the analytical problem of achieving trace detection of ions in concentrated acids or bases by neutralizing the sample using a membrane based neutralizer device. An example of an anion analysis in base is shown here.

 The sample anions are maintained in a water background after neutralization and can be focused onto a concentrator column. In the AutoNeutralization process, the concentrated base sample is loaded into the 25 ul sample loop of the sample valve as shown in the figure below.

The sample loop is switched inline with the concentrator column and flushed with a stream of deionized water. This loading water transfers the concentrated base from the sample loop to the ASRN™, where the sample is partially neutralized, then transferred to the 5 ml loop. The recycle valve is then actuated to direct the sample through the ASRN™ again to complete the neutralization. The figure below shows the results of an anion analysis of a concentrated base sample without and with neutralization. As shown below in chromatogram A, there is a significant negative dip in the baseline due to the concentrated base within the conductivity detector. This matrix interference results in poor chromatography and detection of contaminating anions is virtually impossible. Conversely, chromatogram B shows the results after AutoNeutralization. Note the large negative dip is completely eliminated and distinct anion peaks can be readily measured.