trace analysis of pesticides in food oilsI am pleased to feature two recently released methods for the gas chromatography analysis of pesticides in food oils, such as olive oil and a common food oil.

Those working in food safety testing labs are aware that pesticides are widely used in agriculture and organo-phosphorous pesticides, in particular, due to their relatively low cost, broad spectrum of activity, and high impact on insects compared to other pesticides. But, as organophosphates are known to cause irreversible damage to the nervous system, their presence in food is strictly monitored by regulatory bodies in many countries. (I found an interesting publication, titled, the food we eat: An International Comparison of Pesticide Regulations, (downloadable PDF), that you might be interested in checking out.)

Olive Oil Analysis

Application Note 10049, Trace Determination of Organo-Phosphorous Pesticides in Olive Oil by GC Analysis through PTV Backflush / FPD, (downloadable PDF), describes how this fast and robust method provides extremely high sensitivity and selectivity for phosphorus-containing compounds, and eliminates any interference with the heavy fraction by using a Programmable Temperature Vaporizing (PTV) injector and a Flame Photometric Detector.

A description of the PTV injector’s back-flush device and how it works with our gas chromatography system (Thermo Scientific TRACE Gas Chromatograph) is included. (A previous blog post, How to Use PTV with Backflush on a Gas Chromatograph, explains the steps for the technique in detail.)

The method was successfully used with over 100 injections of oil without replacing the liner or the pre-column, and no degradation of chromatographic performance was observed.

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Food Oil Analysis

Application Note 10128, Tandem GC/MS Analysis of Pesticides in Food Oils by Large Volume Injection with a Back-flush Option, (downloadable PDF), describes a robust analytical method which provides minimal sample cleanup and detects pesticides at very low concentrations in challenging food matrices on a routine gas chromatograph-mass spectrometer system (Thermo Scientific PolarisQ Quadrupole Ion Trap Mass Spectrometer coupled to a TRACE Gas Chromatograph).

The method was tested for over 700 injections and required the ionization volume to be cleaned once and the injection port liner to be replaced once. The injection port septum was replaced every 50 injections.

Additional Resources

  • You might also be interested in our recently released Chromatography Solution Online Center which features many useful and complimentary chromatography tools which can help speed up your analysis. The site is updated on a monthly basis; therefore, do check out the Archives section to see what was previously featured.

If you have questions on the methods, columns or instruments, do enter them in the Comments box below; our experts look forward to hearing from you.