AMMRL: paramagnetic/ ferromagnetic impurities
Thomas M Zennie (ZENNIE_THOMAS_M@lilly.com)
Mon, 10 Dec 2007 16:17:47 -0500
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Esteemed colleagues,
I am trying to analyze organic chemicals in a MeOH effluent that comes
from a heated coiled 316 ss tubing using a flow probe. The fresh spectra
in stop flow mode look very poor with lousy resolution and broad
feature-less peaks. However upon standing in the flow probe in the
magnetic field, after about 3-4 hours or longer (sometime overnight), the
resolution will increase dramatically with excellent peak shape and clean
multiplets.
Upon starting the flow again even just briefly ~ 0.25 ml to 1.0 ml
volume, the resolution goes to hell again. I'm assuming that I am seeing
T2 relaxation effects from leached metals that are resulting in the peak
broadening. Dissolved oxygen is not likely because the solutions have been
standing for as much as days at room temp or in the frig with no
difference in the spectra. Question 1: Any ideas why the spectra get
better upon standing in the probe? I have filtered the samples through a
0.45 um filter before putting them in the flow probe to remove any micro
particulates.
Question 2: How much ferromagnetic or paramagnetic content is enough to
cause the T2 peak broadenings that I am seeing?
Is 10 ppm Fe enough? or 50 ppm Fe? How about Ni or Cr concentrations? ;
all of which are constituents of stainless steel. I have the ICP results
for these metals.
Any ideas would be much appreciated!
***********************************************
Tom Zennie
Lilly Technical Center South
Indianapolis, IN 46285
phone: 317-655-8793 fax: 317-276-4507
Office: IC 110-03-212
email: zennietm@lilly.com
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Esteemed colleagues,
I am trying to analyze organic chemicals
in a MeOH effluent that comes from a heated coiled 316 ss tubing
using a flow probe. The fresh spectra in stop flow mode look very
poor with lousy resolution and broad feature-less peaks. However upon standing
in the flow probe in the magnetic field, after about 3-4 hours or longer
(sometime overnight), the resolution will increase dramatically with excellent
peak shape and clean multiplets.
Upon starting the flow again even
just briefly ~ 0.25 ml to 1.0 ml volume, the resolution goes to hell
again. I'm assuming that I am seeing T2 relaxation effects from leached
metals that are resulting in the peak broadening. Dissolved oxygen is not
likely because the solutions have been standing for as much as days at
room temp or in the frig with no difference in the spectra. Question
1: Any ideas why the spectra get better upon standing in the probe? I have
filtered the samples through a 0.45 um filter before putting them in the
flow probe to remove any micro particulates.
Question 2: How much ferromagnetic
or paramagnetic content is enough to cause the T2 peak broadenings that
I am seeing?
Is 10 ppm Fe enough? or 50 ppm Fe? How
about Ni or Cr concentrations? ; all of which are constituents of
stainless steel. I have the ICP results for these metals.
Any ideas would be much appreciated!
***********************************************
Tom Zennie
Lilly Technical Center South
Indianapolis, IN 46285
phone: 317-655-8793 fax: 317-276-4507
Office: IC 110-03-212
email: zennietm@lilly.com
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