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Ultra Aqueous C18 Columns (USP L1)
Chromatographic Properties:
Highly retentive and selective for reversed phase separations
of polar analytes. Highly base-deactivated. Compatible with
highly aqueous (up to 100%) mobile phases.
Physical Characteristics:
particle size: 3µm or 5µm,
spherical
pore size: 100Å
carbon load: 15%
endcap: no
pH range: 2.5 to 7.5
temperature limit: 80°C
1.0mm ID 2.1mm ID
Length cat.# cat.#
3µm Columns
30mm 9178331 9178332
50mm 9178351 9178352
100mm 9178311 9178312
5µm Columns
30mm 9178531 9178532
50mm 9178551 9178552
100mm 9178511 9178512
150mm 9178561 9178562
200mm 9178521 9178522
250mm 9178571 9178572
Food safety is a topic of great interest globally. With recent
contamination issues in a wide range of commodities, ensur-
ing the quality of our food supply is becoming increasingly
important. Pesticide residue content is one area of concern.
While pesticides have typically been monitored by gas chro-
matography, polar and/or thermally unstable pesticides are
difficult or impossible to monitor using this approach. Thus,
traditional HPLC techniques are used for select pesticide classes, such as the carbamate
and phenylurea pesticides.
With recent advances in LC/MS/MS instrumentation, this technique is quickly gaining
acceptance for pesticide residue testing. LC/MS/MS can be used to simultaneously
monitor hundreds of potential contaminants—including those difficult to detect by
GC. Using both LC/MS/MS and GC approaches allows for a faster, more complete pic-
ture of pesticide residues. MS/MS technology also permits identification of the target
pesticides through the selection of specific MRM transitions for each compound. For
example, aldicarb, a carbamate pesticide, uses two MRM transitions of 208.2→89.1amu
and 208.2→116.1amu.
While the MS/MS detector allows for specific, sensitive detection of the pesticide
species, the LC separation is still important to ensure the highest quality data.
Conventional C18 stationary phases are typically used for pesticide monitoring, but the
selectivity and retention is poor for more polar species. In contrast, Ultra Aqueous C18
columns are ideal for multi-pesticide residue monitoring methods. In Figure 1, the
analysis of more than 280 pesticides using the 3μm Ultra Aqueous C18 is shown.
Optimized stationary phase selectivity allows for an even distribution of the com-
pounds throughout the retention time window (see for peak
lists and retention times). As well, retention of more polar pesticides is greatly
improved, as demonstrated in Figure 1C. The Ultra Aqueous C18 column, in a 100 x
2.1mm, 3μm configuration is the column of choice for LC/MS/MS pesticide monitoring
methods.
Using LC/MS/MS technology and Aqueous C18 columns, in combination with gas chro-
matography, results in the most comprehensive monitoring of pesticide residues. Labs
interested in more complete multi-residue analysis of pesticides in food matrices,
including difficult polar or thermally unstable compounds, should consider adding
LC/MS/MS and Aqueous C18 columns to routine testing procedures.
Acknowledgements
The authors wish to thank the US FDA for their collaboration and recognize the partici-
pation of multiple FDA labs in this work.
For the complete version of this condensed article, visit
Comprehensive Pesticide Residue Analysis by
LC/MS/MS Using an Ultra Aqueous C18 Column
By Becky Wittrig, Ph.D., AB Sciex, and André Schreiber, Ph.D., Applied Biosystems/MDS Analytical Technologies
• Easily resolve and quantify more than 280 pesticide species.
• Use LC/MS/MS to reliably monitor difficult polar and/or
thermally unstable species.
• Aqueous C18 phase offers optimal selectivity and retention.
foods, flavors, & fragrances
More dimensions available online.
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