peak tailling

[May]

I want to develop a GC analysis method for some halogen gases. the column I used is PC- silicaPOLT, the peak tailling is very serious. Is there anybody who met the same problem as me. I'll appreciate it if you can share your apinion with me.

[pochengjean]

Can you give a little more detail? Such as the solvent used?

[May]

actually the samples I need to analyze are gas, the carrier gas I used is hydrogen and the detector is TCD (thermal conductivity detector). I do not know whether the column I choose is correct? or The column is ok, just need to optimize some parameters such as flow rate of the carrier gas, the oven temperature and the volumn size of the sampling loop. actually I have tried what I can do. for example, change the sampling loop size, dilute the sample, optimize the flow rate of the capillary colum, optiamize the ramp rate of the programmed temperature of the oven.

[chromatographer1]

You should try to use a porous polymer packed or capillary column.

Alumina plot capillaries have been used extensively. Silica plot capillary may not have the proper pore opening for the analytes you are measuring. That is probably the cause of the tailing. You need a larger pore silica.

You could also try a cyclodextrin capillary.

Rod

[May]

thank you very much. I really appreciate it.

[pochengjean]

actually the samples I need to analyze are gas, the carrier gas I used is hydrogen and the detector is TCD (thermal conductivity detector). I do not know whether the column I choose is correct? or The column is ok, just need to optimize some parameters such as flow rate of the carrier gas, the oven temperature and the volumn size of the sampling loop. actually I have tried what I can do. for example, change the sampling loop size, dilute the sample, optimize the flow rate of the capillary colum, optiamize the ramp rate of the programmed temperature of the oven.

It is strongly recommanded not to use TCD for active compounds since it has the potential to destroy the TCD filament. Most halogen compounds are considered active.

the tailing might be due to the analyte residue in TCD. You might want to switch your detector to ECD for halogen compounds.