Chromatography Forum

Good day,
I have a problem , that no peak but it is very small (1% of its true earea and heigh). while the same methods of analysis which I have tried give good response and good results on another HPLC device. I have tried to flush the cell (in its site) with hot water and with water/isopropanol.. no benefit.??

First , check the injector.
If it is an autoinjector , fill a vial with mobile phase and weight it using analytical balance , then make 5 times 100 uL injections and weight again.It should be around 500mg less.

If you are making manual injections , and if it is full loop , make sure you are using a syringe at least 5 times the capacity of your loop.

inject your compound without column and measure peak area. This will tell you if problem is with injector or somewhere else (pump is not delivering right mobile phase and your compound is not eluting).

Good day,
I have a problem , that no peak but it is very small (1% of its true earea and heigh). while the same methods of analysis which I have tried give good response and good results on another HPLC device. I have tried to flush the cell (in its site) with hot water and with water/isopropanol.. no benefit.??

Did you try to inject from the same vial on different HPLCs? I am not proud of it, biut I really did make dilution errors by factor 100 reusulting in such a phenomenon .
Also check if your lamp is working well.

Good day,
I have a problem , that no peak but it is very small (1% of its true earea and heigh). while the same methods of analysis which I have tried give good response and good results on another HPLC device. I have tried to flush the cell (in its site) with hot water and with water/isopropanol.. no benefit.??

Did you try to inject from the same vial on different HPLCs? I am not proud of it, biut I really did make dilution errors by factor 100 reusulting in such a phenomenon .
Also check if your lamp is working well.

thanks, yes I did it from the same vial on different HPLC.