Post by David StonePost by rajPost by SassmanPost by raji am new to gc analysis can any one suggest me a method for
organochlorine and organophosphorous pesticides using gc
What instruments do you have available? First you need to choose
what kind of detector you will use. GC/MS would work well for
both classes of pesticides. You could also use GC/ECD for the
organochlorines and GC/NPD for the organophosphates if you have
those available. GC/FID would also work, but sensitivity will
not be great with FID. ---http://www.analyticalchem.com
we have an fid detector and hp-5 column using this can we do the
pesticide analysis
I use "you" below to refer to Raj but Dr. Stone's post seemed like a
good place to throw this in.
If you are planning to analyze pesticide formulations that will be
fine for most analytes. However, if you are doing residue work it will
probably not give you enough selectivity or sensitivity for
practically any analytes.
Post by David StoneThis might be a good place to start if you don't have access to
<http://www.google.ca/search?q=epa+method+pesticide+analysis+GC&ie=ut
f-8&
oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a>
<http://www.google.ca/search?q=chromatography+application+notes+pesti
cide
s&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firef
ox-a>
Also, if you are planning to analyze food for pesticide residues, go
to:
http://www.fda.gov and search for "Pesticide Analytical Manual",
popularly known as the PAM.
It is the traditional bible for analysis of foods for pesticides. Even
if you use more modern methods, like the Quechers and such, a
knowledge of the first few chapters of PAM I (the first of two
volumes)or the equivalent coverage is very useful for perspective.
If you have access to JAOAC, the journal of the AOAC International,
look for work by Fillion; Lehotay; Mercer (separate groups) for a
wide-ranging coverage of gc/ms methods. Mercer's papers use some
interesting and simple SPE cleanup techniques, now codified in the
PAM, in Section 302 (Luke extractions) as cleanup method C6 or C7.
The Quechers technique is very elegant and requires access to the C-18
sorbent they use but, assuming some supply of the sorbent, you can do
extractions from simpler food matrices with very low capital cost.
You will also find that everyone has methods which work fine on simple
samples, like tomatoes. Try dried chilli peppers and that's a
different story, and that's not even all that hard.
Finally, presuming that you are in India, I would suggest talking to
the Spices Board in Cochin or Trivandrum, I forget which. They have
equipment and resources and have access to methods. They do good work,
even on spices.
I believe the European Community charges for copies of its methods but
they do have good methods as well.
If you have access to JAOAC send me some email and I will send you a
list of references which will help you do extractions and cleanups.
That should be useful even given limited instrumentation.
Finally, the more recent editions of the United States Pharmacopeia
(USP) have a chapter on articles of botanical origin and they have
extraction and cleanup methods which are different and interesting.
Their cleanup requires an hplc setup but you may have that available
as well.
- Shankar