Ultra-Low Level Quantification of Pesticides in Baby Foods using an Advanced Triple Quadrupole GC-MS/MS

Importance of the Topic

Accurate quantification of pesticide residues in baby food is critical to meet stringent EU regulations and to protect vulnerable infant populations from toxic exposure. Default maximum residue limits (MRLs) of 10 µg/kg may still pose health risks for certain pesticides, underscoring the need for ultra-trace analytical capabilities.

Objectives and Study Overview

This study evaluates the Thermo Scientific TSQ 9000 triple quadrupole GC-MS/MS system, paired with QuEChERS extraction and HyperSep dispersive SPE cleanup, for the analysis of approximately 200 pesticides in baby food matrices at concentrations as low as 0.025 µg/kg. Key aims include assessing recovery, selectivity, sensitivity, linearity, and long-term robustness under SANTE/10518/2017 guidelines.

Methodology and Sample Preparation

Carrot/potato and apple/pear/banana baby food samples were extracted using citrate-buffered QuEChERS and HyperSep dSPE. Final acetonitrile extracts (1 g/mL) were acidified with 5 % formic acid and spiked with a 211-pesticide mix across 14 levels (0.025–250 µg/kg). Validation involved triplicate spiking at 1.0, 2.5, and 10.0 µg/kg with six replicates each.

Used Instrumentation

• Thermo Scientific TRACE 1310 GC with TraceGOLD TG-5SilMS column (30 m × 0.25 mm × 0.25 µm)
• Thermo Scientific TSQ 9000 GC-MS/MS equipped with Advanced Electron Ionization (AEI) source
• Thermo Scientific TriPlus RSH autosampler for liquid injections
• Thermo Scientific Chromeleon 7.2 CDS for data acquisition and processing

Main Results and Discussion

• Recovery and Precision: Over 97 % of target pesticides showed recoveries between 70–120 % at 1 µg/kg; >90 % achieved LOQ <0.5 µg/kg, and >60 % <0.1 µg/kg.
• Linearity: Calibration over 0.025–250 µg/kg delivered R² >0.990 and RF %RSD <20 % for >96 % of compounds.
• Sensitivity: Instrumental detection limits ranged from ~5 fg to ~2 pg on column (equivalent to sub-µg/kg levels), with >95 % of pesticides <500 fg IDL.
• Robustness: Nearly 900 consecutive injections of matrix extracts maintained full compliance without source cleaning; PTV liner replacement and tuning performed every ~100 injections.

Benefits and Practical Applications

• Direct injection of QuEChERS acetonitrile extracts streamlines workflow and reduces sample handling.
• High-throughput analysis of >200 pesticides across five orders of magnitude supports regulatory and QA/QC demands.
• Exceptional sensitivity permits sample dilution to mitigate matrix effects and extend maintenance intervals.
• Enhanced selectivity and accuracy facilitate compliance with EU infant food safety requirements.

Future Trends and Opportunities

Continued advances in ionization technology and automated maintenance routines will further boost throughput and reliability. Integration of real-time data analytics, expanded residue libraries, and miniaturized sample preparation could extend applicability to emerging and non-volatile contaminants.

Conclusion

The Thermo Scientific TSQ 9000 GC-MS/MS platform with AEI source, coupled to QuEChERS and HyperSep dSPE, enables robust, ultra-trace pesticide quantification in baby food. The method meets strict SANTE criteria, offering outstanding sensitivity, linearity, precision, and long-term stability while enhancing laboratory productivity and regulatory compliance.

References

• European Commission. Plant protection products – MRL guidelines. http://ec.europa.eu/food/plant/docs/plant_pesticides_mrl_guidelines_wrkdoc_11945_en.pdf
• EUR-Lex. Directive on processed cereal-based foods for infants and young children. http://eur-lex.europa.eu/legal-content/EN/TXT/?uri=URISERV:l13002a
• European Union. SANTE/11813/2017 Guidance Document on analytical quality control and method validation for pesticide residues in food and feed.
• EUR-Lex. Directive 2006/125/EC on processed cereal-based foods for infants and young children. http://eur-lex.europa.eu/legal-content/EN/ALL/?uri=CELEX%3A32006L0125
• CVUA Stuttgart. QuEChERS method overview. http://quechers.cvua-stuttgart.de/