green bean, GC-MS/MS, GC-MS, pesticides, TSQ Quantum XLS, Thermo Scientific

Raise your hand if you have ever analyzed samples for pesticides. Keep your hand up if it was pesticides in some type of produce. Now of those with your hands still up, how many of you analyze for more than one type of produce in your lab. My guess is anyone who analyzes for pesticides in produce has many different types of produce to analyze. Ok, y’all can put your hands down. Our goal, as is many of yours, is to create a method that is able to analyze for lots of pesticides in a single injection of our GC-MS/MS triple quadrupole so we do not have to do it more than once. There are a lot of things that make this challenging, not the least of which is sample preparation. Next comes the actual analysis. Methods analyzing for 100’s of compounds are difficult to set up and run. Chromatography is a challenge and typing in all those names can put a cramp in your hands. We took a stab at it. There are methods with 100’s of compounds but this particular one is looking for 303 pesticides and is described in green bean matrix. Using timed-SRM made all the difference in analyzing to low levels with precision.

This application note brings up silly memories from when I was a much younger. When I was a kid my mother was sometimes very silly and had all these rhymes to make us laugh during dinner (probably to have us eat our vegetables too). The one that runs through my mind with this application note is “Eat every bean and Pea on your plate”. For those of you with kids, especially in the US, read that to them, I’m guessing they will laugh. OK, back to the method.

The analysis of 303 pesticides in green bean was evaluated in one analytical run by using the TSQ Quantum XLS series GC-MS/MS triple quadrupole. There were a total of 652 SRM transitions monitored using timed-SRM. This analysis used in combination with standard sample preparation including SPE as a clean-up procedure. Sensitivity can easily reach 0.004 mg/kg for all pesticides in green bean. Linearity and recoveries at 0.010 mg/kg were within the method requirements. Confirmations were demonstrated by using two SRM transitions for each pesticide with goo stability of their ion ratios at different concentrations. Timed-SRM mode is the most effective tool for screening and determining the large numbers of pesticides at low levels in sample matrix. Furthermore, the instrument setup for hundreds of pesticide SRM transitions was simplified by using conditions given in the Pesticide Analyzer Reference, which minimized the complex SRM method development work.

Download application note here; 303 Pesticides in Green Bean