Highly-sensitive pesticide analysis in baby food

Using the SCIEX Triple Quad™ 7500 LC-MS/MS System – QTRAP® Ready, powered by SCIEX OS Software

KC Hyland1 and Ian Moore2
1
SCIEX, USA, 2 SCIEX, Canada

Abstract

The SCIEX 7500 System was used to analyze a panel of 209 pesticides in both neat solvent and baby food matrices. Detection limits of sub-ppb levels were easily achievable with high quality quantitative metrics (reproducibility, peak quality, linear response) even with a dilute sample and small injection volumes. 

11885 7500

Introduction

Detecting and quantifying pesticide residues in food remains a moving target. Analytical technologies continue to evolve, but regulations combined with increased community awareness and public perception of pesticides in foods drive the pursuit of lower limits of quantification. Food testing represents a challenge not only because of the complexity and diversity of relevant matrices but also the need for low-level pesticide detection. 

The technology advancements in the SCIEX Triple Quad™ 7500 LC-MS/MS System – QTRAP® Ready provide significant gains in the generation, capture and transmission of ions into the mass spectrometer.2 The impact of this improved sensitivity was tested with a pesticide panel to assess the absolute sensitivity and other quantitative performance metrics in food matrices. Pesticide levels in baby foods are specifically regulated by regional food safety law, such as the EU Commission Directives of 2006, which set MRL levels for pesticides in baby foods explicitly. In addition to this consideration, commercially available baby foods are an excellent test matrix, as these are homogenous fruit and vegetable blends containing mixes of leafy greens such as kale, high water content fruits such as apples, and high starch fruits such as bananas. This allows for assessment of method performance in a matrix that covers a variety of different types of interferences and backgrounds. This work demonstrated the ability of the high sensitivity SCIEX 7500 System to achieve low level detection limits with a very small injection volume. 

Figure 1. Extremely low concentration detection of pesticides. The pie chart shows the percentage of the analytes in the pesticide panel that were measured at each LLOQ value. The SCIEX 7500 System enables the detection of commonly analyzed pesticide residues at very low levels, allowing the method to leverage very low injection volumes of 1 µL. The translation to detection limits in an original food sample is significant to laboratories testing a wide variety of food matrices for regulated residues. 

Key features of the SCIEX 7500 System for pesticides analysis

  • Limits of detection well below 1 ppb in neat standards for most of the pesticide panel were observed, with plenty of room for the methods to achieve low-level detection with large dilution factors
  • Quantitative performance — including raw sensitivity, linear dynamic range, reproducibility, and instrument robustness were also illustrated
  • Low-level quantification in complex food matrices — fast data collection also allows for tightening chromatographic peak widths without compromising data quality. Chromatographic run was shortened to 10 minutes for 400 MRM transitions using the Scheduled MRM™ Algorithm.
  • The modular design of the OptiFlow® Pro Ion Source provides flexibility with easy switching between ESI and APCI and between LC flow regimes, while maintaining high robustness.