Chromatography Forum

Hello!

I have a Metrohm 883 Basic IC Plus with a Metrosep A Supp 4.0 column. After regeneration of the MSM according to the manual (I suspected contamination), the baseline conductivity increased from around 16 uS/cm to 45 uS/cm. I used 0.2 mol H2SO4 / 20% acetone for regeneration of the MSM. I am using carbonate eluent (1.7 mM NaHCO3, 1.8 mM Na2CO3) and 100 mM H2SO4 as regenerant.

I would be glad to hear any suggestions regarding this issue.

Thank you!

Regards

Hello

I assume that you used 0.2 mol/L for regeneration (not mmol/L).
On one hand, the 0.2 mol/L is not really high concentration for a regenerant. Means you will not remove that much, which was not removed by normal regeneration.
On the other hand, even stonger regeneration does not yield in higher conductivity after wards.

Please make sure that your MSM connection is tight.
Please send me (markus.laeubli@metrohm.com) some example determinations before and after regeneration for a closer look.

Good Morning,

I found this online:

http://ic-help.metrohm.com/maintenance.php?chapter=7_1

EDIT: Markus (above) notes the same thing I did--maybe you used 200 mmol/L H2SO4?

"For the rotors

MSM-HC Rotor A (6.2842.000) / MSM Rotor A (6.2832.000) / MSM-LC Rotor A (6.2844.000) / SPM Rotor A (6.2835.000)

the procedure is as follows:

The inlet capillary for regeneration (regenerant) is connected via the coupling 6.2744.040 to the high-pressure pump. In this way, all three chambers can be rinsed in a reverse flow of 1 mL/min.

MSM / MSM-LC / SPM -> 15 min
MSM-HC -> 45 min

The following solutions are recommended:
- Contamination with heavy metals or with increased backpressure: 1 mol/L H2SO4 + 0.1 mol/L oxalic acid
- Contamination with organic cationic complexing agents: 0.1 mol/L H2SO4 / 0.1 mol/L oxalic acid / acetone 5%
- Heavy contamination with organic substances: 0.2 mol/L H2SO4 / acetone more than 0.2 mol/L H2SO4 / acetone more than 20%."

Best Wishes!