Pesticides Subgroup

Co-Chairs: Steven Moser
Ping Wan


2016 AOAC Pesticide Sub-Group Community Meeting Minutes

September 20th, 2016
 6:15pm – 7:45pm
San Antonio A, Sheraton, Dallas Downtown

We had a very good turnout at the annual conference! Around 40 people attended the subgroup meeting. The chairs updated the subgroup email distribution list.

Collaborative Studies

  • AOAC Collaborative Study for Pesticides in Botanicals GC/MS/MS– Updates from Jon Wong, FDA
    • Protocol finalized: multiresidue determination of pesticides in selected dried botanical dietary supplements by GC/MS/MS. Four botanical matrices will be studied with a target LOQ of 10 ug/kg.
    • Roll out study November 2016
    • Labs interested in participating can contact the subgroup chairs or Jon
  • HRMS + Internet + GIS
    Dr. Pang from the Chinese Academy of Inspection and Quarantine gave a detailed presentation on his work in non-targeted pesticide detection and mapping in China. Electronic reference for pesticides has been established (pesticide identification cards) to replace physical pesticide reference standards; usage of intelligent analyzing system and auto-detection software.
  • Collaborate "Non-target Detection of over 1,200 Pesticides by GC-Q-TOFMS and LC-Q-TOFMS.
    Dr. Pang would like to conduct a future collaborative study using LC-QTOF and GC-QTOF HRMS (2018). Orbitrap users welcome.

Topics of Discussion

  • Labs currently using HRMS for pesticide analysis/screen
    • Is HRMS being used in your laboratory? 
      • To our surprise, around 70% of the attendees reported that they use HRMS in some type of capacity in their daily work! 
      • Advantages: full scan data, high accurate mass, ability for retrospective data mining without the need for re-analysis.  Pitfalls: large data size, clear regulation of criteria of data, well defined criteria for identification.
      • HRMS criteria adopted by USFDA and EU
  • FDA Validation Guidelines:

  • SANTE Validation Guidelines:

    • Future collaborative study on LC-HRMS by Jon Wong
    • Future collaborative study on GCQ-HRMS and LCQ-HRMS by Guo-Fang. Pang
  • Testing pesticide metabolites
    • Metabolites testing is often conducted in labs charged with pesticides in food. C14 labelled studies are conducted to look for metabolites. There is some metabolites data available in CFR.
    • MRLs have not been established for metabolites? Active metabolites that have effects according to the US EPA definition-- must be more than 10% of the residue.
    • Alex Krynitsky mentioned that Symbiotic Research conducts testing with both parents and metabolites. Most polar pesticides produce even more polar metabolites, makes QuEChERS not amenable.  
    • In Europe, registrants have to provide both parent and metabolites to regulatory labs when they register new pesticide compounds.
    • Dr. Pang said they have seen some metabolites during their HRMS study but researched very little about them. Only use is that it served as a quality control for the parent compounds detected.
    • Labs that are running pesticide misuse investigations are not testing non-active metabolites.  Should we start and why is it so hard to prove misuse cases using metabolites in courts?
    • Jon mentioned that FDA is expecting to include metabolites in their future screens. Availability of metabolites is an issue. EPA has provided some metabolites standards to FDA.
    • Fungicides like ethephon, etc. break down very quickly. When solving pesticide misuse cases, degradant might be the only residue left to pursue. Half-life very analyte dependent.
    • Recent cases: Dicamba-ready seeds have been released this year. These soybean and cotton crops are resistant to Dicamba; weeds are killed by Dicamba applications, however other non GMO crops are susceptible to phenoxy damage.
  • Difficult pesticides that the community needs help with
  • Pesticides in Cannabis
    • Cannabis analysis-resin is very similar to GC amenable pesticides, growing industry says it’s a very different to deal with
    • Sticky milling and transferring material is leaving behind-physically difficult to deal with, hard to get enough material to test, cleanup standpoint ion suppression from cannabinoids since they extract well with the QuEChERS, cleanup capacity is huge issue
    • There was a question asked, had anyone tried APCI, API-GC…might be a much better spot with APCI especially with the matrix
    • Julie Kowalski mentioned they looked at GCxGC and got really good results, however the technique is not suitable for the existing testing labs.
  • In Europe, Glyphosate is a big topic. Call for glyphosate methods for collaborative studies:
    • Glyphosate-FMOC derivatization
    • Monsanto glyphosate direct injection with an ion exchange column
    • FDA glyphosate direct injection mixed mode column J. Reg. Sci 02, 2015 Direct determination of glyphosate, glufosinate and AMPA in milk by LC/MS/MS
  • Acid herbicides methods
    • There are currently no AOAC official methods available.  The community suggested that it would be useful to have one.  We will discuss this along with asking the community to provide their methods that they use.
    • Currently we have one method to consider
    • J. Agri. Food Chem 63, 2015. Chris Sack et al.  Determination of Acid Herbicides Using Modified QuEChERS (35 Acid Herbicides Compounds)

Future Plans of Work and Future Meetings

  • GC/MS/MS botanical study Jon Wong (study funded, will be rolled out soon)
  • LC-HR MS collaborative study Jon Wong (do you want to participate?)
  • Acid herbicides methods review (please send us your method!)
  • Glyphosate methods review (possible collaborative study)
  • NACRW - July 23-25, 2017, Naples, FL
  • AOAC  - September 24–27, 2017, Atlanta, GA












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