Addressing Pesticide Contamination

To learn more about the problem of pesticide contamination and how Agilent are helping ensure pesticide analysis is an easier, more robust task we spoke to John Lee, Global Food Market Manager, Agilent Technologies.

John Lee (JL): In Europe the number of notifications around pesticide residues has decreased according to the EU rolled up reporting system called RASFF. Even so last year still saw 435 of these notifications which report on risks identified in food, feed or food contact materials that are placed on the market in the notifying country or detained at an EU point of entry. The number is much higher than for any other category of notification effecting food safety. However there are many risks to food safety and overall in 2014, a total of 3157 original notifications were transmitted through RASFF, including chemical and biological contaminations.

Only 41 of the 435 pesticide notifications were about produce of EU origin the rest resulted from the very significant import of food that is made into the EU.

The problem with food which is contaminated with pesticides above the allowed level, is of course that pesticides are toxic. Of course some are more toxic than others, though this is not always reflected in a proportional way in terms of individual maximum levels set by the EU.

In the RASFF report some of the more toxic pesticides that were responsible for commodity rejection were chlorpyrifos, omethoate, carbofuran, fipronil, methomyl and formetanate. These pesticides (and a number of others) were found in a variety of commodities including green vegetables, aubergine, olives, strawberries, oranges and spearmint leaves, mint and jasmine tea. Some commodities and the countries they come also featured on repeated occasions.

Of course all pesticides are of concern (138 different substances were notified in these 435 cases). Acute toxicity for human health is only one measure. Chronic effects and environmental harmfulness is also a concern from overuse or illegal use of pesticides in food production. And there is also a concern that pesticides can get into food of animal origin through animal feed (six of the notification concerned animal feed).

JL: In Europe there has always been tight regulation but regulation must ultimately be judged according to how strictly it is enforced. With so many potential contaminants (for pesticide alone we are talking over 1000 registered substances) and so many commodities being moved around the globe it would be impossible to cover every eventuality. However the emergence of multiresidue analysis over the last 25 years has improved the coverage of pesticides that are tested per analysis and there are new mass spec technologies now available which are increasing coverage even more. Clearly it’s not only about how many compounds can be analysed but also how quickly and efficiently the analysis can be done. More speed and efficiency means that labs can have more time and money left over to run more samples and hence mitigate more risk. Those efficiencies are now being realized thanks the technology itself getting faster at making measurements and requiring less maintenance.

Are pesticides being used more now than before? It’s very difficult to measure. It is hopefully the case however that more testing is leading to less irresponsible or negligent use of pesticides in food production.

However clearly there is room for improvement and in the meantime hopefully populations are protected by governments funding surveillance schemes like the ones which RASFF reports on each year in Europe.

JL: The first product worth mentioning is a new GC QTOF pesticide screener which we have launched this month and which is based on the very successful 7200 GC QTOF which Agilent launched a couple of years ago. There have always been many pesticides which can only be determined effectively by GC/MS. The GC QTOF screener joins Agilent’s other GC/MS pesticide analysers (GC single quad and triple quad) but offers some unique capabilities which our customers have been asking for. First of all it delivers high resolution accurate mass spectra throughout the course of a chromatographic separation of a food extract. The beauty of these spectra is that they record everything about a sample in an untargeted way. The actual search for pesticides occurs later in the data analysis. This is done using a specially prepared spectral library that contains exact mass spectra and locked retention times for over 850 compounds. These are then looked for at the appropriate place in the separation and a novel matching algorithm is applied. If a lab wishes to expand their analysis for a new compound then as long as it is GC/MS amenable it can be added to the data analysis method with minimum effort. Indeed once done, a lab can even choose to reprocess old data if they need to know whether such a compound was in fact present in previously analysed samples. And whenever a compound is found the lab can have confidence in a result because of the unique selectivity offered through an exact mass library based on the rich fragmentation of Electron Ionisation combined with Agilent’s unique retention time locking approach which allows labs to keep their retention times always the same.

In the world of LC/MS Agilent launched 2 new mass specs this year. The new 6470 Triple quadrupole and 6545 QTOF Mass specs offer excellent performance and value and represent a significant step up in performance over their predecessors the 6460 and 6540. Based on their success, we already know that these new systems are well suited for pesticide analysis. That’s not a small claim. Pesticide analysis requires both instrument types to collect data at high speed and with high sensitivity and stability. And in both cases their value is enhanced through the possibility to buy these instruments with LC/MS Pesticide Application Kits. The LC/Q-TOF kit contains a 1,600-compound Pesticide PCD Accurate Mass Database, and Accurate Mass MS/MS library spectra for more than 500 pesticides, all of which drives data analysis of data which is collected in an untargeted fashion. The benefits are of course the same as for the GC QTOF and together the 2 instruments deliver a complete solution to untargeted screening. The key however is that they can be delivered with a pesticides solution allowing labs to get productive as soon as the instruments arrive. And the methods that we recommend come are informed by our many collaborations with leading pesticide labs around the world so our new customers know they’re going to be achieving the sort of efficiencies that are possible with today’s technology.



Many labs prefer to implement targeted acquisition screening which can still cover 100’s of compounds and can allow a lab to operate very efficiently especially in very high sample throughput situations. For this approach the 6470 is a great fit along with the tMRM Application Kit containing a triggered MRM Database and Library with more than 700 pesticides. This allows spectral verification to avoid false positive reporting, something no labs ever wants to find itself doing. However only Agilent offers this unique confidence technology.

Both LC/MS kits come with 3 columns, a comprehensive pesticide test mix of more than 250 representative analytes and DVD with methods and application notes showing how to these instruments working for a lab’s particular priority pesticide list.

JL: Agilent focusses on making instruments which are inherently reliable and easy to maintain. We also invest in the people we employ to support our equipment at the customer’s lab (some maintenance can be done by the user but there is always the need for expert back up from the manufacturer). However this year there is something else we are doing to further improve the ease with which pesticide analysis can be performed. That has to do with offering a technique which can remove more of the co extractives that can occur in some challenging food matrices. Lipids for example can compromise a pesticide analysis and over time will contaminate the mass spec bringing forward the expense of maintenance and the down time associated. Agilent’s new Enhanced matrix removal-Lipid technology incorporates an innovative sorbent that fits neatly into a QuEChERS workflow to effectively remove lipid co-extractives from high-fat foods without compromising the recovery of target compounds. As a result, analyses can be more selective and reliable, and instrument maintenance can be reduced.

JL: The developments described above are all aimed at making pesticide labs more efficient and able to analyse with more scope. Hence both governments and manufactures can continue to leave less and less space where irresponsible players in the food supply system can hide. However food is grown around the world with some coming from many very small farms that are difficult to control. So there will continue to be the sort of notifications described above in most countries that import their food from global suppliers and testing will continue to be important. As for reduction in use that seems less likely since the world needs more food as population increases and pesticides can increase yields which of course why they came into being in the first place.