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The Use of High Resolution Liquid Chromatography with High Resolution Mass Spectrometry in the Analysis of Pesticides and Other Organic Contaminants in Foods

Eitzer, Brian D
Connecticut Agricultural Experiment Station
Start date
End date
The analysis of organic contaminants in food products is a complex task. Products can be screened for a targeted set of contaminants (such as specific set of pesticides), but the possibility exists that untargeted contaminants could be present.

The goal of this project is the incorporation of liquid chromatography/high resolution accurate mass spectrometry into the analytical procedures used in the Department of Analytical Chemistry at the Connecticut Agricultural Experiment Station for the analysis of organic contaminants in food. This incorporation will greatly expand the list of targeted contaminants as well as assist in the identification of unknown contaminants. Choices of compounds for the expansion of the current targeted compound list of contaminants will come from requests of stakeholders (agencies submitting samples), new pesticides and pesticide metabolites being introduced into agriculture, pharmaceutical compounds, and compounds of interest in ongoing research projects (including research into the decline of managed bees). For each contaminant examined, experiments will be conducted to determine chromatographic retention time, mass spectra, and extraction procedures for produce.
Additionally, we will explore the use of software to assist in the analysis of the large data set that will be generated for each sample. The use of accurate mass data for the identification of unknown compounds will also be explored. Information on the compounds successfully added to our screening techniques will be disseminated to our stakeholders.

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Non-Technical Summary:
Protection of the food supply requires monitoring of the food supply for potential contaminants. These contaminants can come through both intentional (application of a pesticide to a crop) and unintentional means. Determination of the presence and amount of those analytes is a complex task, particularly when it is considered that new potential contaminants are continually introduced. The analytical task is therefore to both monitor the current contaminants as well as to develop procedures for the analysis of new compounds. This project is focused on the incorporation of new instrumentation into the pesticide residue screening program conducted by the Connecticut Agricultural Experiment Station. The instrument is a liquid chromatograph interfaced to a high resolution mass spectrometer. This new instrument is ideal for the determination of trace levels of organic contaminants . Use of this instrument should allow us to add hundreds of additional analytes to the compounds which are routinely analyzed in food products. Additionally, this instrument provides accurate high resolution mass data, these data allow the user to determine possible elemental formulas to help in the identification of unknown compounds. The instrument will be used within our programs for the monitoring of pesticide residues on produce, consumer complaints on food samples, and research on the causes of decline of bees. The outcome of this research is a better protected food supply.

The primary goal of this project is the expansion of the list of targeted analytes. These analytes will be chosen by stakeholder priorities and research needs. The first task for each analyte will be to determine if it can be detected on the LC/HRMS instrument. This will be done by injecting the analyte on the instrument using a standard gradient elution program in both positive and negative electrospray ionization modes at a mass resolution of 100,000. If the analyte can be detected, we will then examine extraction protocols for the analyte. The principal extraction protocol to be examined will be the QuEChERS (Quick Easy Cheap Effective Rugged and Safe) method that is currently employed at the Connecticut Agricultural Experiment Station. In brief, the sample is extracted with acetonitrile, and cleaned up through the use of solid phase dispersants. If that extraction protocol is unsuccessful, alternate protocols will be examined. Unknown contaminants will be identified by comparison of the contaminated samples with uncontaminated samples of the same type of matrix. If an unknown contaminant is found use of the accurate mass data can lead to possible elemental formulas for the compound and potential identification of the compound. Authentic material will then be obtained to confirm the compound's identity before adding it to the target compound list. The success of the program will be gauged by the number of additional compounds added to the standard screening protocol, and by how that results in changes to the number of pesticide residues and other contaminants found in screening programs such as the "Connecticut Market Basket Survey for Pesticide Residues".

2012/01 TO 2012/12
OUTPUTS: This new project is designed to improve the pesticide residue (and other organic contaminants) monitoring procedures of the Connecticut Agricultural Experiment Station by both increasing the number of individual residues that can be monitored as well as improving detection limits for other residues. Several mixed standards have been obtained, which contain hundreds of different pesticide residues. In addition, a mixture of 15 mycotoxins has also been obtained. These mixtures have been screened using high resolution liquid chromatography/high resolution mass spectrometry. We are evaluating operating conditions (resolution, MS/MS conditions, ionization mode etc.) that provide for the best identification and quantitation for a broad range of pesticides. We are currently analyzing all our pesticide residues in produce samples using both our older unit resolution MS/MS system and the new high resolution MS/MS system to compare the capabilities of the two systems. Events and Dissemination: July 16, "The Use of High Performance Liquid Chromatography/High Resolution Mass Spectrometry in Screening Produce for Pesticide Residues" at the Florida Pesticide Residue Workshop, St. Petersburg Beach FL. Sept 12, "QuEChERS Exactive Pesticide Screening Protocol" at the Food Emergency Response Networks cCAP meeting, Cincinnati, OH. Oct. 9 and Oct. 11 "The Use of High Performance Liquid Chromatography/High Resolution Mass Spectrometry in Screening Produce for Pesticide Residues" at the Thermo-Fisher Scientific LC/MS User Meetings in Somerset, NJ, and Cambridge, MA.
PARTICIPANTS: Dr. Brian Eitzer is the principal scientist working on this project. Some of the samples to be analyzed are prepared by Dr. Walter Krol and Ms. Teri Arsenault.
TARGET AUDIENCES: The primary target audiences for this Hatch project are the agencies, such as the Connecticut Department of Consumer Protection, the Connecticut Department of Energy and Environmental Protection and the U.S. Food and Drug Administration that use the pesticide residue data generated by the Connecticut Agricultural Experiment Station. Secondary target audiences include the public whom are interested in the safety of the food supply.
PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

IMPACT: The goal of this project is the enhancement of the pesticide residue monitoring program of the Connecticut Agricultural Experiment Station. During the past year, seven pesticide residues were found for the first time in our ongoing survey of pesticide residues in Connecticut produce. These residues were only identified because of the high resolution mass spectrometry procedures being introduced as part of this project. These residues are cadusaphos, carbosulfan, fenuron, kresoxim-methyl, spinosad, and spiridoclofen. Furthermore, three samples, which contained some of these residues, were reported to the Connecticut Department of Consumer Protection (DCP)as being violative; these were a turnip sample from Massachusetts which had 0.002 ppm fenuron, a basil sample from Columbia with 0.017 ppm cadusafos and a pepper sample from China with 0.089 ppm carbosulfan. In all three cases there was no tolerance for these residues on that commodity. As none of these commodities were from Connecticut the DCP passed the information on o the Food and Drug Administration for further action.

Funding Source
Nat'l. Inst. of Food and Agriculture
Project source
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Accession number
Chemical Contaminants
Food Defense and Integrity
Bacterial Pathogens