Chromatography Forum

I tried to analyze the content of pesticides (cyfluthrin) in the liquid Using GC Shimadzu
I use agilent packed column 100%-dimethylpolysiloxane (L: 15 m, ID: 0.53 mm, Film : 1.5 µm), split ratio 1: 1
The result is peak chromatography breaks and resolution is not good,
Then I try to use smaller collumn, agilent packed column (50% -phenyl) -Methylpolysiloxane (L: 30 m, ID: 0.32 mm, Film : 0.15 µm), split ratio 1: 1 and the result is the same.
I've used different types of temperature variations (detector: FID), the split ratio variation and the resolution still not good (the peaks breaks)

Are the columns I use do not match?
I need advice for this analysis

Thanks
Vienna

Why are you reinventing the wheel? See attached;

https://pubs.usgs.gov/tm/tm5c2/tm5c2.pdf

1) These are capillary columns, not packed ones.

2) Splitting 1:1 ?? Is this even possible?

Either split more 1:20-1:100 (if you work in high concentrations closer to ppm values) or work splitless (low concentrations closer to ppb levels).

Why are you reinventing the wheel? See attached;

https://pubs.usgs.gov/tm/tm5c2/tm5c2.pdf

Thanks

1) These are capillary columns, not packed ones.

2) Splitting 1:1 ?? Is this even possible?

Either split more 1:20-1:100 (if you work in high concentrations closer to ppm values) or work splitless (low concentrations closer to ppb levels).

The concentrate is low, near to ppb level
I've use any variation of split ratio, from 1:20-1:100
But I never use splitless.
Can I Use splitless mode for capillary column with ID 05-0.32 mm?
Isn't it will shorten AFC Lifetime?

1) These are capillary columns, not packed ones.

2) Splitting 1:1 ?? Is this even possible?

Either split more 1:20-1:100 (if you work in high concentrations closer to ppm values) or work splitless (low concentrations closer to ppb levels).

The concentrate is low, near to ppb level
I've use any variation of split ratio, from 1:20-1:100
But I never use splitless.
Can I Use splitless mode for capillary column with ID 05-0.32 mm?
Isn't it will shorten AFC Lifetime?

People use those columns all the time with splitless injections. If you are not using a guard column(retention gap) stick with 1ul injections. You may also want to have some glass wool in the inlet liner to help vaporization.

Also look at this for helping to lower your detection limits

http://blog.restek.com/?p=6009

http://blog.restek.com/?p=9670

I have been working with this some and it does actually work, doing large volume injections with a normal split/splitless injection port.