1,4-Dichlorobenzene-d4 retention time?
Posted: Sun Jun 29, 2025 5:56 pm
I am using a Markes TD system attached to a Shimadzu GCMS to analyze air for VOCs on SS adsorbent tubes. I am working on building a calibration curve using a BTEX mix at varying known concentrations from 25ppb to 10ppm, and an internal standard of 1,4-dichlorobenzene-d4 at 10ppm in all the tubes.
I can “see” the BTEX on the chromatograms, but not the 1,4-DCB-d4. I think I selected an IS that is way outside of my BTEX mix range in terms of RT. Do you think that’s the case? I triple checked my concentration.
Benzene RT is about 2.25 minutes followed by TEX, ending with O-Xylene around 5 minutes. My entire run is about 12 minutes.
I can get details of the column specifics and GC method parameters (temps and He flow) when I get back to the lab.
(I am a retiree from 35 years in the environmental industry now pursing my PhD, have only a few months of hands-on GCMS experience, and our lab manager who I would ask is on vacation for the next week…)
I can “see” the BTEX on the chromatograms, but not the 1,4-DCB-d4. I think I selected an IS that is way outside of my BTEX mix range in terms of RT. Do you think that’s the case? I triple checked my concentration.
Benzene RT is about 2.25 minutes followed by TEX, ending with O-Xylene around 5 minutes. My entire run is about 12 minutes.
I can get details of the column specifics and GC method parameters (temps and He flow) when I get back to the lab.
(I am a retiree from 35 years in the environmental industry now pursing my PhD, have only a few months of hands-on GCMS experience, and our lab manager who I would ask is on vacation for the next week…)