Chromatography Forum

Our lab recently received a grant to conduct biodegradation research on TCE, and we need to be able to measure the entire chlorinated ethene chain (Trichloroethene, cis-Dichloroethene, and Vinyl Chloride). In the past, we've done this with headspace + ECD, but have never been able to get any detectable Vinyl Chloride, and have always chalked it up to the lack of a trap in our headspace analyzer.

Luckily, we got some money in the grant to purchase a new GC and headspace trap to replace our outdated and crippled PE autosystem. We absolutely NEED to be able to measure VC for this round of experiments - and after talking to some colleagues, are getting mixed advice. Some say we should go with the ECD + headspace trap, while others are saying that we won't get VC repeatably with an ECD, and should go with a PID detector. Due to cost constraints, a GC/MS isn't an option for us. What do you think?

unhpian,

ECD is not a very good detector for VC due to the single chlorine. Much better to use a PID due to the double bonds in the list of compounds you put forth. PID runs into trouble if you want to do the chlorinated alkanes (many of which have IP's above 10.2) but does pretty well on the chlorinated alkenes.

Sampling is also a constraint when you are trying to catch VC. No headspace in the vials, rapid analysis, good loading technique, etc... are all very important.

Best regards.