Chromatography Forum

Our lab's IC has been running inorganic anions with AS18 columns. We just came across a stash of never-used new-in-box AS4A columns (and the corresponding guard columns) from a prior Dionex system 20 years ago (!), which prompted two questions: 1) are they compatible for anions on the ICS-2000, and 2) will they have survived long storage (always room temp, and still in as-shipped condition)?.

Hi
What a luck to find a AS4A; probably in the big blue box? You have to know, the AS4A incl. guard is a so called carbonate selective column. The normal eluent conditions are 1.7mM Na2CO3 / 1.8mM NaHCO3 and isocratic. The AS18 you use now is a hydroxide selective column. I assume therefore that you use an eluent generator with your ICS-2000 which is not compatible with Carbonate eluents. Considering the age and the low capacity of the AS4A (the AS4A was developed late 1980) i would store the column in the museum.
Best, Stefan

Dear ICagain
if you are curious give it a try with the eluent Stephan mentioned. you even may can can change the carb/bicarb ratio. This might show you interesting possibilities of the column.
But for routine work I also wound not change a working system.

I checked the ThermoFisher website and they still list them for sale at $1500.

For fast, isocratic separation of inorganic anions in environmental waters, the Thermo Scientific™ Dionex™ IonPac™ AS4A-SC column was the preferred column for many years. It was first introduced in 1984 and is the specified column in U.S. EPA Method 300.0 (A). However, the advanced, high-capacity Dionex IonPac AS22 Carbonate Eluent Anion-Exchange column is recommended for fast analysis of inorganic anions in diverse matrices when using carbonate eluents.

Maybe someone somewhere still uses them. List them on e-bay and see if anyone wants one.