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DETERMINATION OF PESTICIDE RESIDUES IN BIOLOGICAL EXTRACTS BY RETENTION TIME LOCKING CAPILLARY GAS CHROMATOGRAPHY MASS SPECTROMETRY
Citation:
ROSAL, C. G. AND G. MOMPLAISIR. DETERMINATION OF PESTICIDE RESIDUES IN BIOLOGICAL EXTRACTS BY RETENTION TIME LOCKING CAPILLARY GAS CHROMATOGRAPHY MASS SPECTROMETRY. Presented at 28th International Symposium on Capillary Chromatography and Electrophoresis, Las Vegas, NV, May 22 - 25, 2005.
Impact/Purpose:
The overall goals of the task are to apply NERL's core capability in advanced chemical science and technology for maximum benefit in estimating exposures of ecosystems and humans to chemical stressors and to identify emerging pollution concerns, in particular long-range airborne transport of contaminants. This task comprises several subtasks, each with individual objectives:
Subtask 1: screen exposures of National Park PRIMENet ecosystems to chemical stressors, identifying indications of exposure requiring further evaluation, and use these samples evaluate new analytical methods as replacements for standard methods in future assessments of ecosystem contaminant exposures.
Subtask 2: evaluate a new mercury analytical approach with superior performance on complex solid matrices such as biological tissues, and apply the approach to estimating exposure of ecosystems and humans to mercury.
Subtask 3: determine distribution patterns of chemical contaminants in the southern Sierra Nevada Range of California, investigate topographic and weather factors that may influence the distributions, and determine if a correlation exists between contaminant distributions and extirpation patterns of the mountain yellow-legged frog.
Subtask 4: provide analytical methods to measure a number of inorganic and organic arsenic species in a variety of environmental matrices, elucidate the environmental transformations undergone by organoarsenic animal-feed additives, and determine if the potential exists for substantially increased exposure of humans and aquatic organisms to arsenic.
Description:
The widespread use of pesticides in agricultural and urban areas (golf course and residential lawn applications) is largely responsible for the presence of these compounds in many water bodies. Transported by storm-waters, irrigation runoffs, wind, and treated and untreated sewage, many of these compounds reach the receiving waters unchanged while others are transformed into chemical entities that can be more toxic or more available to biota. One way to monitor the transport of these contaminants is by screening the biota exposed to the waters.
In this study, samples of frog and fish were analyzed for pesticide residues found in lawn fertilizers and other commonly used agricultural pesticides. Whole sample homogenates were extracted, and the resulting extracts Were taken through a silica fractionation to remove non- target contaminants.
The final extracts were analyzed by capillary gas chromatography-mass spectrometry (cGC-MS) with retention time locking (RTL). The RTL-cGCMS method was developed in house and was used previously for the trace determination of agricultural pesticides in "pristine" waters. The analytical results obtained using the RTL-cGCMS approach were confirmed using the Agilent RTL screener software in combination with the Agilent RTL pesticide library. Preliminary results of this study will be presented.