Chromatography Forum

We want to do sugar profile from food, mainly glucose, fructose, sucrose, lactose and maltose. We have a Dionex system, but we have a problem with it. For sucrose it is not sensitive and the peak is wide, small, and not symmetric. Our system is isocrtaic, but now we have a reagent free generator, but when I set up for gradient the baseline is rising very much but after it stabilise slowly, but I cant use as a gradient. So I am using only for cleaning the column. Now I have a program which is 40 min with cleanig but without maltose. It is very long.
I was following this forum, but unfortunately i did not get answer for my questions.
1. What is the typical calibration stds and LOD individually? Mine is 50-400 ppm, but 50ppm for sucrose is my LOD.
2. Can you achieve 0.995 calibration in linear easily? Because now it is hard. OR should I use other calibration? I checked them but the results are still not good. So the repeatability is not good.
3. We are thinking to switch over to HPLC-RI, I used to work with it, but I can not remember the LOD. I want 0.1 g/100g for food. Can I achieve this. This would be around 10-50 mg/l stds individually.

Thank you very much your answers and help.

This would be around 10-50 mg/l stds individually.

That would be difficult by RI.

If you are having problems with the PAD detector on the Dionex, probably the best bet would be to contact Dionex tech support.

We want to do sugar profile from food, mainly glucose, fructose, sucrose, lactose and maltose. We have a Dionex system, but we have a problem with it. For sucrose it is not sensitive and the peak is wide, small, and not symmetric. Our system is isocrtaic, but now we have a reagent free generator, but when I set up for gradient the baseline is rising very much but after it stabilise slowly, but I cant use as a gradient. So I am using only for cleaning the column. Now I have a program which is 40 min with cleanig but without maltose. It is very long.
I was following this forum, but unfortunately i did not get answer for my questions.
1. What is the typical calibration stds and LOD individually? Mine is 50-400 ppm, but 50ppm for sucrose is my LOD.
2. Can you achieve 0.995 calibration in linear easily? Because now it is hard. OR should I use other calibration? I checked them but the results are still not good. So the repeatability is not good.
3. We are thinking to switch over to HPLC-RI, I used to work with it, but I can not remember the LOD. I want 0.1 g/100g for food. Can I achieve this. This would be around 10-50 mg/l stds individually.

Thank you very much your answers and help.

CAD if matrix is compatible IMHO

If you are having problems with the PAD detector on the Dionex, probably the best bet would be to contact Dionex tech support.[/quote]

I contacted tech support, but I still have problem,. I have this instrument for a half a year and unfortunately I could not start to validate the method.

What was their response?

agi1124, please get in contact with me directly and I will assign one of our Global Regional IC Technical Support Managers to work with you on your integrated amperometric (ICS-3000 or ICS-5000?) Dionex systems for your sugars application.

Once we are able to review the details of your case (column, electrode type, chemistry, actions performed, Chromeleon backup files, etc.) we can offer specific recommendations to help you get back on track.

Look at the Biorad Aminex columns (87H etc) literature available on the Biorad website. Using an isocratic eluent (dil sulfuric acid approx 5-20 mM) and RI detection you can do some good work and newer RI detectors are very good just recycle eluent, leave pumo and det on all the time, etc. The tradeoff is between PAD and RI headaches...

Hi here is the parasit. I'm trying to put on an ICS-3000 with pulsed amperiometric detector. I'm very interested, if possible in the working range you can obtain for these sugars. What column are you using?
Pardon for my english