While these rules are welcomed to maintain food safety, particularly for babies, more sensitive technologies are required to keep up with any future regulatory changes and ensure standards are being met. Despite these concerns, no further changes to MRLs in baby foods have yet been implemented – partly due to the availability of suitable analytical methods. Here, we explore the challenges in the ultra-sensitive determination of pesticides in baby food, and how triple quadrupole gas chromatography-mass spectrometry (GC-MS/MS) can provide effective and confident analysis to meet strict regulations.
Staying competitive in changing circumstances
The main challenge with meeting regulatory requirements is the ability to implement more sensitive analytical techniques for determination of hundreds of different pesticides at ultra-trace levels in a single analysis. While current methods can be effective, further improvements to laboratory set‑ups are required to meet these uncompromising quantitation levels.
Compounding the matter further, baby food analysis is complex, because the final products are often comprised of many different ingredients. The complexity of the sample matrix can present challenges for extraction and clean-up, and cause interference with detection – and hence quantitation – of ultra-trace levels of residues in a ‘heavy matrix’.
Baby food analysis is complex because the final products are often comprised of many different ingredients
As well as addressing these concerns, meeting customer expectations is essential. Laboratories require a high sample throughput, fast turnaround, and must be cost effective. Most importantly, the method also needs to comply with SANTE analytical quality control and method validation guidelines in force at the time of the analysis.4
Triple quadrupole GC-MS/MS can meet all these challenges for GC-amenable pesticides, which covers most of the older obsolete compounds of concern. So how can GC-MS/MS play a role in adhering to MRLs while increasing customer satisfaction?
A simple solution using GC-MS/MS
Gas chromatography, when coupled to triple quadrupole mass spectrometry with advanced electron ionisation (AEI), constitutes a highly sensitive and selective technique for detecting pesticide residues. In a study we conducted, samples were prepared for analysis using a QuEChERS (quick, easy, cheap, effective, rugged, and safe) small-scale extraction procedure.
While pesticides offer overall benefits to food production, manufacturers and regulatory bodies need to find ways to make baby food production safer for consumers
The QuEChERS acetonitrile extraction, combined with dispersive solid phase extraction (dSPE) clean-up, has revolutionised multi-residue analysis. Operationally smooth, the method provides excellent recovery and precision for a wide number of analytes. No additional maceration of sample in the solvent is needed, so less labware is required – and because of the low acetonitrile volume and reduced amounts of reagents, less waste is produced. It’s this operational simplicity, sustainability credentials, higher productivity and compatibility with GC-MS that makes the approach attractive for analytical laboratories. Furthermore, QuEChERS methods are commercially available at low cost, reducing the time required for analysts to weigh the various combinations of chemical reagents employed for different sample types.5
Not only is GC-MS/MS user-friendly, its high sensitivity makes it perfect for meeting strict regulations. As mentioned earlier, the complexity of some food makes ultra-trace level detection challenging; fortunately, GC-MS/MS provides acquisition methods that overcome this. For example, time-dependent selected reaction monitoring (t-SRM) enables the residues chemist to monitor multiple characteristic ion transitions for different pesticides, without loss in sensitivity. This means you can confidently quantify and identify the target pesticides, even at ultra-trace levels.
Effective pesticide testing in baby food samples
A recent application note showcases how our laboratory, in collaboration with the European Reference Laboratory for Pesticide Residues in Fruit and Vegetables (EURL-FV), used triple quadrupole GC-MS/MS for ultra-trace pesticide residue detection in baby food.6 The latest Thermo Scientific TSQ 9610 triple quadrupole mass spectrometer equipped with a Thermo Scientific NeverVent AEI ion source was coupled to a Thermo Scientific TRACE 1610 gas chromatograph featuring a Thermo Scientific iConnect programmable temperature vaporising (iConnect PTV) injector and a Thermo Scientific AI/AS 1610 liquid autosampler.
Several baby food samples containing different ingredients were pre-spiked with more than 200 pesticides at varying concentrations prior to extraction using the QuEChERS EN Method. Blank and spiked samples were analysed using a 1.0μL spitless injection, and chromatographic separation was achieved using a Thermo Scientific TraceGold TG-5SilMS capillary column. The results of the experiments undertaken to evaluate the linearity, detection limits and repeatability of the method demonstrated the following:
- SANTE criteria: Sensitivity (S/N>3 for at least two product ions), identification (ion ratios within ±30 percent of the average of calibration standards), recoveries (70-120 percent) and precision (≤10 percent RSD) were compliant with SANTE/12682/2019 guidance document.*
- Linear dynamic range: Wide linear response and quantitative performance were obtained for all the tested pesticides over the range 0.05-500 µg/kg.
- Excellent detection limits: Calculated instrument detection limits ranged from six to 650fg on-column, corresponding to 0.006 to 0.65 μg/kg across all pesticides tested. More than 95 percent of compounds achieved LOQs ≤1 ug/kg.
- Robustness: A stable detector response was observed during continuous injection of more than 500 sample extracts (various sample types in a randomised order) over four weeks with minimal maintenance.
GC-MS/MS provided excellent results across many baby food matrices including fruits, vegetables, potatoes and rice. In each case, we were able to discriminate between the spiked pesticides and the matrix with a high level of confidence. All these factors make GC-MS/MS with AEI a powerful tool for meeting new regulations, while enabling quick sample turnaround and excellent customer service.
Working together for a healthier future
While pesticides offer overall benefits to food production, manufacturers and regulatory bodies need to find ways to make baby food production safer for consumers. Risk assessment projects require determination of pesticides at levels as low as possible – typically below 0.001 mg/kg – meaning increasingly sensitive techniques are needed as standard. Additionally, under the European Union Green Deal there is an objective to use at least 25 percent of agricultural land for organic farming by 2030.7 It is therefore likely that ultra-low detection of pesticides will be required to detect any mislabelling and misuse. Enforcing good agricultural practices through regulatory measures sets an excellent foundation for safer food.
Recent technology advancements such as GC‑MS/MS with AEI and other productivity features are excellent systems to monitor pesticide residues at ultra-low levels in baby foods – while being flexible and adaptable for future monitoring requirements. With more laboratories embracing this technology, we can uphold food safety standards for generations to come and collaborate for safer and more effective agricultural production and food preparation practices.
References
- 1. European Commission, Guidelines – Maximum Residue levels, https://ec.europa.eu/food/plants/pesticides/maximum-residue-levels_en
- https://www.efsa.europa.eu/en/efsajournal/pub/5286
- Commission Directive 2006/125/EC of 5 December 2006 on processed cereal-based foods and baby foods for infants and young children, https://eur-lex.europa.eu/legal-content/EN/ALL/?uri=CELEX%3A32006L0125
- EC SANTE/12682/2019, Analytical quality control and method validation procedures for pesticide residues analysis in food and feed. Implemented 01/01/2020.
- https://ec.europa.eu/food/system/files/2020-01/pesticides_mrl_guidelines_wrkdoc_2019-12682.pdf
- https://assets.thermofisher.com/TFS-Assets/CMD/brochures/br-000249-ccs-original-dispersive-european-br000249-na-en.pdf https://assets.thermofisher.com/TFS-Assets/CMD/Application-Notes/an-000437-gc-ms-pesticides-baby-food-an000437-en.pdf
- https://ec.europa.eu/info/food-farming-fisheries/farming/organic-farming/organic-action-plan_en#organicsintheeu
