Bio-Rad Chelex® 100 Resin - Manual (Page 10)

Metal Analysis with Chelex Resin
Many methods of metal analysis, such as neutron
activation and atomic absorption, depend on the prior
separation and concentration of the metals from such
samples as air, soil, industrial waste waters, and bio-
logical extracts. Trace metals can be concentrated by
adsorption to Chelex chelating resin. The use of
Chelex resin to preconcentrate samples for analysis
has been extensively reviewed.
1 Determination of sub-
nanogram levels of Cd, Co, Cu, Fe, Mn, Ni, Pb, and
Zn can be achieved by using Chelex 100 resin 200-
400 mesh, with graphite furnace atomic adsorption
spectrometry.
2 Chelex 100 resin is also effective in
concentrating traces of Cd, Co, Cu, Mn, Ni, Pb, and
Zn from various food digests. Average recoveries
were 98.1% determined with standards.
3
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neither column nor batch treatment with Chelex 100
resin has any effect on protein concentration or
enzyme activity. Where low protein recovery is a
problem, the protein can be dialyzed against a buffer
containing Chelex 100 resin. Table 2 gives examples
of trace metal removal with Chelex 100 resin.
Glyphosate Concentration with Chelex
100 Resin
Chelex 100 resin may be used to concentrate
glyphosate [N-(phosphonomethyl) glycine] when the
resin is in the iron form. When environmental water or
an aqueous extract of crops such as soybeans, grapes,
cabbage, or alfalfa is applied to Chelex 100 resin
(100-200 mesh, iron form), glyphosate complexes
with the iron form Chelex 100 resin. The glyphosate
may subsequently be eluted with 6 M HCl and applied
to AG
® 1-X8 resin (200-400 mesh, chloride form) for
anion exchange cleanup. The glyphosate along with
AMPA (aminomethyl phosphonic acid), its break-
down product, may then be quantified with the
Aminex
® glyphosate analysis column.
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LIT200B 6/17/98 11:50 AM Page 16