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Trying to calibrate my GC 6850

elirodrigues

Hi everyone,

 

I'm having some problem with my method.

Not sure exactly what it is:

Couple of days ago I've replaced the column of my GC-6850 with a shorter column ( 30m - 320mm).

I had to integrate the peaks with the new length of the column.

I normally use two methods to run my samples:

One is longer (ramp) and the other one is shorter with no ramp.

I can calibrate the longer method with no problems.

But when i load the shorter method it is not possible to calibrate the machine.

 

I've noticed that when I run a blank test (no injection) on short method it picks up the compound that I'm analyzing.

When I run the same Blank on longer method the peak disappears.

 

Standard Run (104ppb)

 

 

Blank Run (no injection)

 

 

I'm afraid that I've got a contamination and the peak on short run is not correctly integrated.

 

Sorry I can't explain better.

I'm very new in this field and I'm looking for some help in trying to understand better my software.

 

Please help.

 

Tanks.

Parents
  • 0

    Hello

    the area amount of the starndard is the one you expected? I don't see much difference between the blank and the std run, its seems like the FID is working but there is a leak somewhere, maybe in the injector? No solvent peak?

  • 0 in reply to dmarchini

    Hi there,

     

    thanks for replying.

     

    When I run the standard it gives me the correct amount in all three runs that I perform before start the tests.

     

    We work with air samples.

    The samples are collected using PP plastic syringes;

    They are sent to the lab for testing;

    The syringe is then attached to the inlet port of the GC and the sample is injected manually;

    2ml of sample is hold in the 6 port valve (adapted for our type of sampling Technic);

    Once the GC is ready the sample is taken automatically from the 6 port valve into the column.

Reply
  • 0 in reply to dmarchini

    Hi there,

     

    thanks for replying.

     

    When I run the standard it gives me the correct amount in all three runs that I perform before start the tests.

     

    We work with air samples.

    The samples are collected using PP plastic syringes;

    They are sent to the lab for testing;

    The syringe is then attached to the inlet port of the GC and the sample is injected manually;

    2ml of sample is hold in the 6 port valve (adapted for our type of sampling Technic);

    Once the GC is ready the sample is taken automatically from the 6 port valve into the column.

Children
  • 0 in reply to elirodrigues

    For our standards, a peak as you show in the chromatogram is unacceptable, its seems more like a baseline noise doubled peak.....I would try anyway to get better response and an accettaple peak size/shape increasing at least 5 times the injected volume or doin a splitless injection injectin high volume.

     

    We work with air samples collectin it in TEDLAR BAGS with septum of the volume of 5 liters using a pump or without a pump if the gas emission is under pressure then we directly inject using these Agilent gas syringes

     

    -P/N 5190-1523 500uL gas syringe

    -P/N 5190-1528 1000uL ga syringe

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