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For Removal of Metal Ion Contamination and Restoration of Proper
Ion Balance in Glyphosate Analytical Columns and Guards
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INTRODUCTION
Glyphosate herbicide analysis by post-column HPLC according
to USEPA Method 547 employs a cation-exchange column. Many
polyvalent metal ions which may be present in the sample,
especially iron, will accumulate in the guard or analytical
column. As little as 100 nmole of ferric ion, for example,
will cause serious degradation of column performance; larger
amounts can actually cause the glyphosate peak to vanish completely.
Note: The use of a guard column containing
the same cation resin as the column is strongly recommended,
as the guard will normally trap all of the metal ions, and
will be the only column requiring the use of RESTORE. Tests
in our laboratory have demonstrated that the guard can accumulate
sufficient iron to completely absorb glyphosate without
bleeding Fe+3 into the analytical column.
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The traditional metal removal process using EDTA requires a long
treatment time, and an even longer re-equilibration period. Glyphosate
RESTORE rapidly removes iron, nickel, aluminum, and chromium from
the column and guard. The column and guard are ready to use after
only a very brief re-equilibration with the K200 (potassium phosphate)
eluant.
Glyphosate RESTORE is strongly acidic and can displace tenaciously-bound
Fe+3 from the ioin-exchange medium. In addition, it preserves
the balance of K+ and H+ in the resin, thus
avoiding a lengthy re-equilibration.
COLUMN CLEANING PROTOCOL
Guard Column:
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Remove the analytical column after ensuring that no residual
pressure remains in the post-column system.
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Reverse the guard column and pump RESTORE through the guard
at 0.4mL/min. for a minimum of 15 minutes, directing the effluent
to waste.
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Pump the K200 eluant through the guard for 15 minutes to displace
RESTORE.
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Reconnect the columns in the normal directions and restart the
HPLC and postcolumn systems.
Analytical Column:
Apply the procedure above, but pump RESTORE through the column
for a minimum of 45 minutes.
Note: Since Glyphosate RESTORE is strongly acidic (pH
1.3), do not allow it to remain in your HPLC pump longer than
necessary.
ORDERING INFORMATION
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1700-0140 |
RESTORE for removal of
metal ion contamination from glyphosate columns, 250 mL |
The shelf life of a factory-sealed 250 mL
bottle of RESTORE is estimated at two years.
Restore is a trademark of Pickering Laboratories,
Inc.
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