Robert Clifford (1), Laura Chambers (1), William Lipps (1), Nicole Lock (1); (1) Shimadzu Scientific Instruments, Columbia, MD, U.S.A.


From a consumer safety point-of-view, quantitation of the pesticide residues in hops has begun to attract wide interest. There are several problems associated with analysis of pesticide residues in hops. First and foremost, there are very few regulatory guidelines established to define which pesticides to include or what the detection limits should be. In fact the U.S. government’s 40 CFR Part 180 states individual tolerances must be established for miscellaneous commodities intentionally not included in any group including hops. Second, the matrix is very complex, with significant interferences. Finally, sample load is growing exponentially, so the chosen method must be quick and easy to perform. Trace level pesticide analysis in complex food matrices has been done for many years with similar challenges, thus many of the analytical protocols emerging for the hops matrix are based on these well-established techniques. Triple-quadrupole GC-MS/MS operated in MRM mode provides significant sensitivity and selectivity, but method development can be expensive and time-consuming. This poster describes a streamlined method development process for analysis of 34 pesticide residues in hops using a QuEChERS sample preparation method, followed by GC-MS/MS detection and quantitation. The pesticides are from five classes of compounds, including organonitrogen, organophosphorus, organochlorines, carbamates, and synthetic pyrethroids.

Robert Clifford received his bachelor’s degree from Glassboro State College, now Rowan University, in New Jersey, his master’s degree from Villanova in Pennsylvania, and his Ph.D. degree from George Washington University in Washington, DC. He has published and presented over 100 papers in the fields of food, pharmaceutical, environmental, energy, geology, material science, photonics, and marijuana. However, his true love is foods and beverages. His first chemistry job was as a summer intern at the Campbell Soup Company, where he was hired as a full-time employee. After he went back to graduate school he took another job as an intern at the FDA, where he was also hired as a full-time employee. After graduating with his Ph.D. degree he left the FDA for Shimadzu, where he has worked for the last 25 years. His current title is marketing manager of food and consumer products.