Analysis of sodium hydrogen carbonate (also known as sodium bicarbonate) for anionic contaminants is critical due the large amount of CO2 formed during suppression. Even applying sequential suppression does not completely remove the interferences due to the carbonate peak. The introduction of Inline Neutralization applying the Sample Preparation Module (SPM) with subsequent CO2 removal with the MCS (Metrohm CO2 Suppressor) prior to the injection solves the problem. After this pretreatment, the sequentially suppressed sample is analyzed without issues.