Chromatography Forum

I am a researcher in Dept. of Pharmacology and Toxicology at Balıkesir University/TURKEY. I have used HPLC more than 20 years for drug analysis in animal and human plasma. In Balikesir University, 3 years ago I preferred Agilent and got Agilent 1260 series HPLC with a binary pump, DAD (G4212A) and Fluorimetric detectors for my lab. Both detectors have serially connected the system (firstly DAD and then Fluorescence detector) by Agilent service in Turkey. The system has been working until last month. During the sequence, the flow cell (G4212-68001) of the DAD detector was blocked.
I checked the support documents of the 1260 series HPLC. Agilent recommended S/S tubing for connection between column and DAD detector in all documents. Moreover, for G4212-60007 and G4212-60008,
The use of Peek-FS capillaries is not recommended. In combination with the SST zero dead volume fitting (e.g. at the inlet) the capillary could break and the glass particles could block/damage the flow cell.is not recommended. In combination with the SST zero dead volume fitting (e.g. at the inlet) the capillary could break and the glass particles could block/damage the flow cell.is not recommended. In combination with the SST zero dead volume fitting (e.g. at the inlet) the capillary could break and the glass particles could block/damage the flow cell.
The pressure relief valve is designed to protect the flow cell of an Agilent 1200 Infinity Diode Array Detector (G4212A/B). Agilent strongly recommends installing the pressure relief valve at the outlet of the detector as soon as a second detector is installed like in LC/MS applications.

Agilent service had been used PEEK tubing between the column and the flow cell of the DAD detector. Moreover, my system does not have a pressure relief valve and the service person had never checked pressure for the requirement of the pressure relief valve.

I contacted the Agilent service in Turkey and explained all these. However, they have never accepted the use of wrong tubing and requirement of the pressure relief valve. They request 3000 dollars for replacement of the flow cell. This is not acceptable. I think the flow cell was blocked because of the mistake of Agilent service (PEEK tubing instead of S/S tubing used between column and DAD detector) or the absence of a pressure relief valve.
I am looking forward to hearing any response!
Kind regards
Prof. Cengiz GOKBULUT

Did you try reverse-flushing the flow cell?

We had an Agilent flow cell once where the small capillary of the flow cell got plugged, and we were able to replace just that.

a flow cell might get blocked for tons of different reasons....it will be almost impossible to prove that the cause is the peek tubing. But a blocked flow cell might not be so close to death as you think, do you have the flow-cell cleaning kit? If not try reverse-flushing the system with 50/50 water/methanol (no column of course). Once a friend of mine actually placed the flow cell while connected to the pump into a ultra-sonic bath....i wouldn't dare that because of the glass....but it worked in his case (too risky for me...but if nothing else works, what do you have to loose but a junk flow-cell that you have to throw away afterwards anyway)

Thank you for your reply.
This flow-cell (G4212-68001) is different from the former flow cells. Agilent does not recommend reverse-flushing the flow cell and They say that the repairing of this flow-cell was not possible.

Hocam merhaba ,

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Thank you for your reply.
This flow-cell (G4212-68001) is different from the former flow cells. Agilent does not recommend reverse-flushing the flow cell and They say that the repairing of this flow-cell was not possible.

And if i here such a statement i get suspicious.....ok you can buy a new one and throw the old one away, no harm in that. But than you can isolate the flow cell and try reverse flushing before throwing away....

As a side note: Did they use PEEK (that is, plain-vanilla PEEK)? That should be no problem. As you wrote yourself, PEEK-FS (!) is not recommended. This is PEEK-clad fused silica, which is very different from plain-vanilla PEEK.