Agilent 8890, GC-ECD, Headspace, Chromatography
Posted: Sun Jul 21, 2024 3:03 pm
Hi there. Just a simple lab tech here looking for some opinions on my chromatography. I'm open to providing any necessary information. In the chromatograms, blue represents an air blank, cyan indicates a matrix sample containing some analyte, and purple denotes a mid-level binary calibrator.
The tests were conducted on an Agilent 8890 using a newly conditioned column and a fresh detector, employing headspace analysis with a split ratio of 5:1. The method maintains the oven at 65°C until the two-minute mark, after which it ramps up to 195°C to facilitate a mini bakeout, causing the baseline to rise towards the end.
My primary concern is the 2,3-Butanedione analyte. Its peak, occurring near the end of the solvent peak, leads to a sloped baseline. The unusual hump and dip at 2.05 and 2.1 minutes, along with the tailing of the analyte peak, are concerning at a glance, and I'm unsure of the best integration method. Currently, we achieve an R2 of 0.9993 with a three-point calibration, integrating by drawing the baseline horizontally. While our recoveries and reproducibility are mostly satisfactory for our purposes, we do perform some manual-integration-magic. 2,3-Butanedione serves merely as an indicator of fermentation completion in beer production.
I welcome any advice, comments, or suggestions you may have. Thank you!
PS - I'm not quite sure how best to view these chromatograms. How 'good' my analysis looks seems highly dependent on the scale of the X and Y. I also forgot to add that all PMs are up to date, we recently changed our syringe, split vent filter, o rings, liners, and our leak tests looked great.
My images are broken, maybe this works: https://imgur.com/a/chromatography-ryFozCD
The tests were conducted on an Agilent 8890 using a newly conditioned column and a fresh detector, employing headspace analysis with a split ratio of 5:1. The method maintains the oven at 65°C until the two-minute mark, after which it ramps up to 195°C to facilitate a mini bakeout, causing the baseline to rise towards the end.
My primary concern is the 2,3-Butanedione analyte. Its peak, occurring near the end of the solvent peak, leads to a sloped baseline. The unusual hump and dip at 2.05 and 2.1 minutes, along with the tailing of the analyte peak, are concerning at a glance, and I'm unsure of the best integration method. Currently, we achieve an R2 of 0.9993 with a three-point calibration, integrating by drawing the baseline horizontally. While our recoveries and reproducibility are mostly satisfactory for our purposes, we do perform some manual-integration-magic. 2,3-Butanedione serves merely as an indicator of fermentation completion in beer production.
I welcome any advice, comments, or suggestions you may have. Thank you!
PS - I'm not quite sure how best to view these chromatograms. How 'good' my analysis looks seems highly dependent on the scale of the X and Y. I also forgot to add that all PMs are up to date, we recently changed our syringe, split vent filter, o rings, liners, and our leak tests looked great.
My images are broken, maybe this works: https://imgur.com/a/chromatography-ryFozCD