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Melamine at Trace Levels
LC-MS method for analysis of trace levels of melamine. Excellent retention with simple MS compatible mobile phase.
Method Conditions
| Column |
Cogent Diamond Hydride™, 4µm, 100A |
| Catalog No. |
70000-15P-2 |
| Dimensions |
2.1 x 150 mm |
| Solvents |
A: DI water + 0.1% formic acid
B: Acetonitrile + 0.1% formic acid |
Mobile Phase
(for each run) |
I: 60% B, isocraic
II: 70% B, isocraic
t0 = 1.44 min.
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| Flow Rate |
0.4 mL/min. |
| Sample |
Melamine m/z 127 (M+H+)
(166.7 µg /mL of compound in 50% acetonitrile / DI water + 0.1% acetic acid. Run 1:1000 dilution in 80%
acetonitrile / DI water +0.1% acetic acid).
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| Injection |
5 µL |
| Detection |
ESI – pos - Agilent 6210 MSD TOF MS. |
Discussion
In this application, melamine was analyzed under ANP conditions using a Cogent Diamond Hydride™ column. A high percentage of
acetonitrile used in the mobile phase shows an increased sensitivity for the analyzed compound. The method is suitable for detection
of melamine at trace levels. The unique chemical properties of melamine (base functionalities, causing the predominant form of the
compound to be pH dependent) present challenges in obtaining retention and adequate sensitivity, when using LC-MS on standard HPLC
columns.
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Note: Several dogs and cats died or were seriously ill after consumption of pet foods which had been manufactured with
adulterated wheat glutens. After testing of the wheat glutens it was determined that they contained significant levels of
melamine and/or several related compounds. There is a need for an accurate and simple analytical method for health hazard
evaluation of melamine, especially after traces of this compound were found in baby food as well.
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