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low level rl's for naphthalene using purge and trap
Posted: Wed Jan 30, 2013 4:34 pm
by chloesabrina
Any luck with running naphthalene meeting a RL of 0.5ppb? I am going to try a larger volume purge and see what I can do, but just curious.
Agilent 6890
Encon purge and trap
Archon autosampler
Will be trying on the soil side first.
Re: low level rl's for naphthalene using purge and trap
Posted: Wed Jan 30, 2013 11:30 pm
by Steve Reimer
I can get enough response to see 0.5ppb with no problem if I am only looking for the 128 peak. The problem is that I get nasty samples and naphthalene is very persistent. With my system (6890/5975 OI4660 - Archon) a larger purge wouldn't be as helpful as careful screening.
The response is usually quadratic at low levels.
Re: low level rl's for naphthalene using purge and trap
Posted: Thu Jan 31, 2013 12:49 pm
by chloesabrina
I have the same problem with the samples - unfortunately even though some of these samples have to be diluted for naphthalene the client still wants a RL of 0.5ppb without running it by EPA8270. I ran a 10ml purge last night with an ical only going to 25ppb so I'm hoping to achieve the goal.
Re: low level rl's for naphthalene using purge and trap
Posted: Thu Jan 31, 2013 3:14 pm
by Yama001
I'll concur with Steve - detecting naphthalene at 0.5 ug/L is doable - not detecting it in clean samples is the problem.
Re: low level rl's for naphthalene using purge and trap
Posted: Thu Jan 31, 2013 5:53 pm
by chloesabrina
Great sounds good, thanks. These are definitely not clean
Re: low level rl's for naphthalene using purge and trap
Posted: Fri Feb 01, 2013 5:45 pm
by Bigbear
Works for me. Do 524 see down to 0.5 ppb. purge 25ml.
Re: low level rl's for naphthalene using purge and trap
Posted: Fri Feb 08, 2013 7:20 pm
by James_Ball
I have the same setup and can see 0.5ppb with little problems. We purge 5ml sample.
What type of trap are you using?
What is your split ratio?
What GC column?
I use a custom packed trap with Carboseive SIII, Carboxen1000 and CarbopackB. Similar to the VoCarb3000. For Naphthalene use a Vocarb3000 or Vocarb4000 or possibly the BTEX trap. The biggest problem I have so far is the carryover of Naphthalene, but if you run the transfer lines at 130c and use the 5ml sparge tube and rinse with 8ml DI after a 5ml sparge it helps.
Been running purge and trap for twenty years and still there isn't a day I don't see some new problem with it. Just keeps things exciting
Re: low level rl's for naphthalene using purge and trap
Posted: Fri Feb 08, 2013 7:36 pm
by chloesabrina
Thanks James_Ball
I use the Voacarb 3000, DB624 column with a 1:50 split. I was actually able to see it with the 5ml purge and get a decent result +-30% after chopping off most of my upper points and just leaving 6 points with a quadratic curve.
I will have a really hard time of it if some of site gets cleaned up since the carryover will be awful. So far I have never reported anything below 5ppb for them.
I have only been running purge and trap for ~8 years now, but it is my favorite since it never gets old.
