Acrylamide Monomer by GC-ECD (EPA 8032)
Posted: Tue Feb 14, 2012 2:52 pm
Hey,
Was wondering if anybody could help with a slight problem I’m having with a method. We are using a Perkin Elmer Clarus 500 GC-ECD to analyse monoacrylamide and methacrylamide brominated to 2,3 dibromopropionamide after a two day reaction and series of extractions with Ethyl acetate based on EPA method 8032.
I originally used the Rtx-35, 15m column with 0.32mm ID 0.5 µm. The GC method has an injection at 80oC, holds for 1minute, ramps at 15oC/Min to 200oC, holds for 2minutes with a 1uL split/splitless injection. The injection temperature is 180oC with the Split injection coming on at -0.1minute to 1minute when it becomes splitless with 20ml/min split. The ECD detector is at 250oC and our carrier gas is Nitrogen. I started to notice a lot of contamination signified by ghost peaks in the chromatograms particularly at the retention times of the compounds of interest.
As the column had quite a long lifetime I changed the column to an Rxi-35Sil MS, a 30m with a 0.32mm ID 0.25 µm. I have tried different starting temperatures from 60C, 70C and 80C with various splits and injection volumes trying to maximize the focus on the column.
I can get separation of the peaks of interest but my problem is that we have been unable to obtain good reproducibility and a steady calibration when analyzing samples/standards the expected peak for 2,3 dibromopropionamide is not appearing consistently with differing concentrations/spikes of the compound.
Does anybody have any ideas as to why this could be the case? I am suspicious that a portion of the sample is being trapped in the liner or being blown out as waste when the carrier gas is introduced (as per split/splitless injection), but again I am open to investigate any suggestions on offer. I have tried quite a few combinations but would still like to hear others ideas?
Best Regards
KC
Was wondering if anybody could help with a slight problem I’m having with a method. We are using a Perkin Elmer Clarus 500 GC-ECD to analyse monoacrylamide and methacrylamide brominated to 2,3 dibromopropionamide after a two day reaction and series of extractions with Ethyl acetate based on EPA method 8032.
I originally used the Rtx-35, 15m column with 0.32mm ID 0.5 µm. The GC method has an injection at 80oC, holds for 1minute, ramps at 15oC/Min to 200oC, holds for 2minutes with a 1uL split/splitless injection. The injection temperature is 180oC with the Split injection coming on at -0.1minute to 1minute when it becomes splitless with 20ml/min split. The ECD detector is at 250oC and our carrier gas is Nitrogen. I started to notice a lot of contamination signified by ghost peaks in the chromatograms particularly at the retention times of the compounds of interest.
As the column had quite a long lifetime I changed the column to an Rxi-35Sil MS, a 30m with a 0.32mm ID 0.25 µm. I have tried different starting temperatures from 60C, 70C and 80C with various splits and injection volumes trying to maximize the focus on the column.
I can get separation of the peaks of interest but my problem is that we have been unable to obtain good reproducibility and a steady calibration when analyzing samples/standards the expected peak for 2,3 dibromopropionamide is not appearing consistently with differing concentrations/spikes of the compound.
Does anybody have any ideas as to why this could be the case? I am suspicious that a portion of the sample is being trapped in the liner or being blown out as waste when the carrier gas is introduced (as per split/splitless injection), but again I am open to investigate any suggestions on offer. I have tried quite a few combinations but would still like to hear others ideas?
Best Regards
KC