Chromatography Forum

Hi,
I am working in Pentachlorophenol(PCP) anlysis by GC-MS. I tried PCP in GC-ECD.But it didn't work.Can anyone guide me. the GC details are below
Inj Temp : 260 C
Oven : 70- 150 @10c/min,150-220@2c/min
ECD : 320 C
Column : DB-5

Can anyone suggest me a suitable extraction method for the detection of PCP in egg.

Thanks & Regards

Seeni

Mr. Seenivasan,

Did PCP in plain solvent not work or is this an extraction problem? I am sure you will have an extraction problem but lets start with analysis and work our way back to extractions, shall we?

You should not have problems with PCP by ECD on DB-5 so that is the first thing to work out., eh. Column dimensions, flow rates, injector conditions (split/splitless...) and what levels?

(Looking to the future, lots of "junk" in an egg, so more information on that would be appreciated...)

Best regards.

You might wish to consider derivitization. Any 'garbage' from the egg in a carryover might make any column too reactive to elute PCP as a sharp peak.

In additional you should have a very clean injector to get trace amounts of PCP to the detector reproducibly.

best wishes,

Rod

Thank you so much for the reply.I have no problem in analysing PCP in water by GC-MS.I usually extract with n-Hexane and inject.But i couldn't follow the same method for the Hen Egg, because it contains 60 % fat. Normally i use florisil column to remove the fat.But this is not working in the case of PCP extraction from Hen Egg.No recovery is seen after florisil column cleanup.Can you suggest me suitable extraction methods?

Regarding GC-ECD i had injected 0.1ppm of PCP Standard.Now i'll increase the concentration and do it again.

Kind Regards

Seeni

I would investigate a flash chromatography system to separate the remaining 'junk' from the PCP.

Matrices affect separation and isolation of analytes to an enormous degree.

Good luck in your research. Look through the journals carefully.

best wishes,

Rod

Mr. Seenivasan,

I would recommend GPC cleanup. PCP should elute very late on standard Bio-bead columns since it is a relatively small molecule. You can build a system for under $2500 if you don't mind doing some manual labor to cleanup your samples and you have a spare UV detector. I did this for a customer of mine. You can get the standard for calibrating the GPC with corn oil and PCP from someone like Accustandard to give you the exact time you want to cut your collection fraction. The process does use quite a bit of solvent but it would be very effective for what you want to do I think.

Best regards.

Thanks again.I would like to know about the cleanup system as you mentioned.I am ready to invest.I have enough manhours to work.Will you suggest some details in this regard?

Kind regards

Seeni

Mr. Seenivasan,

You need:

A solvent pump like the Fluid Metering company (FMI) variable volume pump,
a switching valve like the Rheodyne 5020 low pressure injector,
a column like the Omnifit 250 mm X 25mm,
Bio Beads SX-3 or equivalent,
about 3 meters of 1/8 " teflon tubing,
various tubing fittings, and useful but not essential, a
254 nm UV detector.

For the system I built I bought the UV detector as a used variable wavelength unit that was very inexpensive on LabX. You don't have to buy the detector, the other way to determine the proper cut is to collect fractions either for an off line UV spectrometer or run by GC but this is sort of tedious..

I simply took the outlet of the column and place it in a waste container for a period of time, then manually switch to collect for a small fraction of time and then back to waste to finish cleaning the column. There is an EPA method for this cleanup but I don't have the method number in front of me at the moment. As I recall, I built the whole thing for under $3K US with a new pump, valve and column and a used UV detector.

A bit labor intensive but very effective and inexpensive.

Best regards.