Highly sensitive quantification and selective identification of pesticides in food with Zeno MRMHR

Using the SCIEX ZenoTOF 7600 system, powered by SCIEX OS software

Robert A. Di Lorenzo1, Lukasz Rajski2, Jianru Stahl-Zeng3, Jason Causon1
SCIEX, Canada; 2EURL-FV, Universidad de Almeria, Spain; 3SCIEX, Germany


Using the sensitivity enhancements of the Zeno trap, Zeno MRMHR is used to quantify low levels of pesticides in oilve oil and various fruits and vegetables to meet global regulations for pesticide residues. Over the mass range analyzed, the Zeno trap allowed for signal gains of 5-15x, with negligible increase in noise due to the selectivity of MRMHR analysis, hence gains were directly related to improved LLOQs. The selectivity and specificity afforeded by the accurate mass MS/MS quantitation on the ZenoTOF 7600 system allowed for highly confident identifications of pesiticdes in real food samples (MS and MS/MS mass accuracy, library matching, isotope ratio matching), while still maintaining triple quad-like ability to perfom ion ratios for confirmations. 



In order to ensure safety in the global food supply, testing for adherence to federal and international requirements is necessary. The tests monitor for chemical residues, including pesticides, microbial and fungal toxins, and microbiological hazards. Considering the ever-growing demand on the food supply, farmers and producers are tasked with optimizing yields, which means employing the use of pesticides to deter pests from harming their crops. For this reason, it is important to be aware of adherence to pesticide maximum residue limits set by the appropriate governing bodies.

Traditionally, pesticide residue analysis has been performed by triple quadrupole mass spectrometers, due to their sensitivity and quantitative power. Accurate mass instruments can afford additional levels of confirmation, however they have traditionally suffered from a lack of sensitivity and precision, especially when performing MS/MS experiments to meet the testing requirements for the regulatory guidelines. The technological enhancements afforded by the ZenoTOF 7600 system, however, bring QTOF systems into a new era of sensitivity and precision. 

Figure 1. MS/MS peak area gains as a result of enabling the Zeno trap on the ZenoTOF 7600 system. Sensitivity improvements during MS/MS experiments using the Zeno trap are a result of regaining >90% of duty cycle related losses. For this reason, the improvements are dependent on the upper limit of scan range and the measured mass of the MS/MS fragment. The theoretical gain curve is constructed based the scan parameters acquired in this experiment. 

Key feature of Zeno MRMHR for pesticide quantification

  • Highly sensitive pesticide detection with a high degree of selectivity and identification confidence using Zeno MRMHR
  • In-matrix LLOQs below 0.010 mg/kg to meet global pesticide regulations
  • Quantification using accurate mass fragment extracted ion chromatograms cuts through noise and interferences, simplifying peak detection and integration to eliminate manual peak review
  • Identification confidence using accurate mass precursor and fragments (< 5 ppm mass error or < 1mDa below 200 Da), ion ratios (± 30%) and MS/MS spectral library matching
  • High speed analysis ensuring ample points across each chromatographic peak, even with highly-multiplexed analyses
  • Easy data filtering and data review with SCIEX OS software.