ICS 3000

[aqawwas]

hii
Is there someone who uses DIONEX ICS 3000

[WillyOne]

Yes I "suffer" one ICS 3000. May I help you?

[Mark Albertson]

Hi WillyOne,

What exactly is your problem?

[WillyOne]

I have had problems with the equipment but to talk about them I would prefere to send you a private e-mail. I've looking your profile but didn't found your e-mail address there. If you are so kind to send me your e-mail address I will send you my claims against it.
Another question that I feel this is the place to talk over is the column.
I'm using a 250 x 4 mm Carbopack PA-10 to analyze Major sugars components in foods and beverages. I'm trying to analize Glucose, Fructose Saccharose, Maltose and Lactose.
Until moment I've injected 10 microliters of a standar solution of 100 ppm of the first three sugars.
Flow is 1,2 m/min and composition around 25 mM NaOH during 12 min then changes to 200mM NaOH during 10 min to regenerate and finally 6 to 8 min to retrieve initial conditions. The detection is done by a PAD with the quadruple waveform Dionex reccomends for Carbohydrates in Chromilion.

The first run in the morning shows good separation between Glucose ad Fructose and well shaped peaks. There is an horizontal baseline between them but at higher signal level that I can see in the baseline before and after the full group of peaks. I can't understand why it happens.

The following ones show leading peaks and separation Glucose-Fructose is only a valley quite elevated.
The RT are slightly changing from run to run
With these conditions is not easy an automatic integration.
The regeneration of the column each run is a punishment and it seems that 10 min is not enough.
I will have a 45 min run for a 12 min analysis.
am I doing something wrong?, All wrong?

Excuseme, my english is quite bad

[SeanAustin]

Hi Serena

We have an ICS 3000 system - mostly working quite well - but obviously not all the time. I'll be interested to hear about your issues and see if we have any matching ones.

Regarding your sugar separation - PA 10 is not as good as the PA 1 for this separation. We developed a method using the PA 20 recently but that was not straight forward and didn't save much time over the PA1. We are now considering the new SA10.

Anyway, it is perfectly normal to have long re-equilibration times - I think your 6-8 mins are a bit short normally we run about 15-20 min re-equilibration ! If your samples are not too dirty a possible way round this is to run isocratically for a set number of injections (10 for example) then run a cleaning gradient and requilibration then go on with the next group of samples ..... but that depends on what you are analysing ... food samples can be very messy.

Just a quick question - Does your ICS 3000 have a temperature controlled column compartment ... and are you using it ?? Temperature fluctuations do make your peaks move around. We normally try to run at temperatures at least 5°C above room temp if possible.

Hope some of this helps you.

[WillyOne]

Thanks a lot per your interest.
Well, about the column, we followed the advice of the Dionex applications specialist (Vertex in Spain), and bought the PA10. These columns are very expensive, I have not budget to buy a new one
Now I'm trying to follow your advice, enlarging the equilibration time (and now I have a 45 mins run).
Just today I've charged samples to look for linearity.
Conditions:
Flow 1,2 ml/min
From 0 to 12min 24mM NaOH
12 to 17 gradient to 200 mM NaOH
17 to 27, 200 mM NaOH (regeneration)
27 to 32 gradient to 24 mM NaOH
32 to 45 equilibration time at 24 mM NaOH
It will work over the weekend and I hope I will have results monday morning.
The other advice you proposed me was the temperature, and I feel that's very important.
Yes I've choosen 25 ºC for column compartement and 30ºC for PAD but I feel that my mistake is that I don't wait enough time before begining the runs. Perhaps my erratic RT are caused because the column was not temperature equilibrated.
I'll see monday morning.
Again thanks a lot

[SeanAustin]

Hi

How did it go ??
You can probably save a couple of minutes in your method ... I would try to drop from 200mM NaOH to 24mM NaOH from 27 to 29 min (possibly even from 27 to 28 min).

Good luck...

[WillyOne]

Well, That I did was to keep powered the column and PAD ovens all the time.
So I did obtain repetitive RT from the 3rd run to the end of the sequence. It means that I only need 90 mins to equilibrate the system and that is an amelioration in my life.
Second problem: I run the ICS 3000 coupled with an Ultimate 3000 Autosampler column compartment. Injecting 5 µl the deviation in consecutive runs is as wide as 20 %.
I've tryed linearity from 10 to 100 ppm of the 5 sugars injecting two times each of the ten standars.
Any suggestion to improve repetibility?

[SeanAustin]

Hi

Are you using full loop injection ?? If not - then that's the first thing to do to improve your repeatability.

Second thing ..... if you have a system like ours (we have a dual pump system with a single autosampler) there is quite a bit of dead volume between the sample loop and the autosampler needle. Recent experience showed that even if we use a 20uL loop in full loop mode the repeatability was not good enough. However we then told chromeleon to make a 200uL injection on our 20uL loop - repeatability with this was fantastic..... but it eats up samples and standards !

Ah ...but now I am thinking about the Ultimate 3000 autosampler ..... its different from the one on the ICS 3000 ..... I am not sure you have what I would describe as a "normal" type of sample loop ??

Here are some typical issues we have had with autosamplers that may help you - but I have to say that so far we have not had a problem with repeatability on the Ultimate 3000 systems.

- check there are no air bubbles in the syringe (and/or loose connections to the syringe)
- use pre-slit tops on the sample vials - we found poor repeatability when using other types of caps on some instruments.

One other thing - what type of electrode are you using on your PED ? A gold electrode, or do you have these new disposable ones??

.... good luck

[WillyOne]

Well I've followed your advice:
Syringe bubbles:
Yes I had. I didn't realized because they are formed when the syringe pulls from the vial not when it pulls from the washing reservoir, and the test I did was washing cycle.
My fault has been to be too much cautious. The nuts I have to connect syringe and needle to the Peek Rheodyne Valve are metallic and I was afraid to break the valve.
Furthermore, the U-3000 design is so nice that its front cover hides the syringe.
About the vials, I haven't pre-slit caps for vials.
I've prepared the linearity (again...) and capped the vials with "Parafilm".
The answer tomorrow morning.
Any way thanks a lot

[WillyOne]

Hey Sean
The final solution was using uncapped vials.
I've tried to add the image of the calibration report I obtained,(straight lines, Correlation Coefs % ranging from 99,92 to 99,99) but it seems I haven't the permissions to do attachements.
I'm in debt with you.
Next time I will pay for the beers
Thanks a lot
G.