Degradation of pesticides in food and beverages: Implications for risk assessment Open Access

Radford, Samantha Adkins (2012)

Permanent URL: https://etd.library.emory.edu/concern/etds/2f75r828h?locale=en
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Abstract

Abstract
Degradation of insecticides in food and beverages: Implications for risk assessment
Samantha A. Radford
Insecticide metabolites have been used for years as biomarkers of exposure to parent
insecticide compound under the assumption that there is a one-to-one correlation between
urinary metabolite output and insecticide exposure. However, if insecticides degrade in
food before it is eaten, the degradates produced are likely to be chemically equivalent to
urinary insecticide metabolites excreted by the human body. Therefore, the degradates
produced could be mistaken for metabolites of parent compound produced in the body.
In this case, insecticide exposure would be overestimated. For this reason, we have
studied the degradation of insecticides in food via two methods. In the first experiment,
beverages were fortified with insecticide and extracted for both parent and degradation
products. Degradation of insecticides in the beverages was suggested both by the loss of
the parent compound and the production of degradates. As further evidence that the loss
of insecticide was actually degradation and not some other mechanism such as insecticide
adsorption to glass storage jars, it was shown that there was no statistical difference in
insecticide concentrations from samples containing insecticide stored in standard amber
glass jars, silanized amber glass jars, or vortexed amber glass jars after seven days of
storage. In the second study, a sample of fruit and vegetable baby foods was collected
and analyzed for both insecticides and their degradation products. The insecticides and
their degradation products were found in many of the baby food samples. Further, these
analytes were found in baby foods labeled as organic as well as in conventional baby
foods. Together, these studies demonstrate the need for better understanding of the

relationship between insecticide degradation products and urinary insecticide metabolites
so better estimations of the population's exposure to insecticides may be made.

Table of Contents

Table of Contents ABSTRACT ACKNOWLEDGEMENTS LIST OF FIGURES LIST OF TABLES LIST OF ACRONYMNS CHAPTER 1: INTRODUCTION AND BACKGROUND............................................. 1 Current insecticide use and history of insecticide regulation in the United States........................................................................................................... 2 Health outcomes associated with insecticide exposure........................................... 6 Use of biomarkers to monitor human exposure to insecticides............................. 11 Past research on insecticide degradation in food.................................................. 15 Background information on insecticide classes..................................................... 18 Proposed investigations......................................................................................... 31 CHAPTER 2: METHOD DEVELOPMENT FOR THE EXTRACTION AND SEPARATION OF INSECTICIDE DEGRADATION PRODUCTS FROM BABY FOODS............................................... 34 Hypothesis............................................................................................................. 35 Introduction........................................................................................................... 37 Method.................................................................................................................. 40 Results................................................................................................................... 39 Discussion.............................................................................................................. 45 Conclusions............................................................................................................ 47 APPENDIX A: DEVELOPMENT OF LIQUID CHROMATOGRAPHIC METHODS FOR INSECTICIDE DEGRADATES, MALATHION, AND DAPS............................................................... 49 Separation of insecticide degradation products by LC-MS/MS........................... 50 Separation of malathion by LC-MS/MS................................................................ 59 Method development for the liquid chromatographic separation of dialkyl phosphates 63 CHAPTER 3: DEGRADATION OF INSECTICIDES IN BEVERAGES................... 72 Hypothesis............................................................................................................. 73 Introduction........................................................................................................... 73 Methods................................................................................................................. 77 Results................................................................................................................... 87 Discussion............................................................................................................ 115 Conclusions.......................................................................................................... 125 APPENDIX B: OTHER STUDIES OF INSECTICDE DEGRADATION................ 127 Liquid-liquid extraction....................................................................................... 128 QuEChERS analysis............................................................................................ 133 Degradation of insecticides in solid food............................................................ 137 First test of degradation using MS/MS detection............................................... 139 Repeat test of degradation using MS/MS detection........................................... 143 Conclusions.......................................................................................................... 151 CHAPTER 4: STUDY OF INSECTICIDES AND INSECTICIDE DEGRADATES IN BABY FOOD......................................................................................................................................... 152 Hypothesis........................................................................................................... 153 Introduction......................................................................................................... 153 Methods............................................................................................................... 155 Results................................................................................................................. 164 Discussion............................................................................................................ 173 Conclusions.......................................................................................................... 177 CHAPTER 5: SIMPLIFICATON OF INSECTICIDE EXTRACTION METHOD FOR UNDERGRADUATE EXPERIMENTS....................................................................... 178 Hypothesis........................................................................................................... 179 Introduction......................................................................................................... 179 Method................................................................................................................ 180 Results................................................................................................................. 186 Hazards and notes............................................................................................... 188 Conclusions.......................................................................................................... 189 APPENDIX C: ANALYSIS OF PESTICIDES BY GAS CHROMATOGRAPHY Introduction......................................................................................................... 191 Procedure............................................................................................................. 193 CHAPTER 6: CONCLUSIONS AND FUTURE WORK........................................... 195 APPENDIX D: STRUCTURES OF REFERENCED INSECTICIDES..................... 200 CHAPTER 7: REFERENCES....................................................................................... 212

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