Dr. Amadeo R Fernández-Alba, EURL for Fruits and Vegetables, University of Almería

The EU Reference Laboratory (EURL) for Fruits and Vegetables in Almería is responsible for a network of around 200 laboratories which provide essential surveillance and monitoring to ensure the safety of foodstuffs available across Europe. The EURL provides proficiency testing and method development for these official laboratories, ensuring rigorous screening to avoid harmful chemicals entering the food chain.Find out more about the SCIEX X500R QTOF System >

The production of fruit and vegetables for human consumption is a vital industry for many agricultural regions of Europe, as well as many non-EU countries which supply the common market. Regulation and control of pesticide use in the production of these foodstuffs are essential to ensure that the public is not exposed to high levels of chemicals which could be detrimental to their health. Routine testing of fruit and vegetables destined for national markets is performed by a large network of laboratories across the EU, as well as around 25-30 laboratories in countries with close economic ties to Europe, overseen by the EURL for Fruits and Vegetables.

The laboratory, housed in the Department of Hydrogeology and Analytical Chemistry at Spain’s University of Almería, is led by Professor Amadeo R Fernández-Alba. He explained the laboratory’s role: “We began developing new techniques for pesticide detection in food samples over 20 years ago, using a combination of gas chromatography with single quadrupole mass spectrometers and liquid chromatography with UV detection, before moving on to LC-MS. Our original scope was fairly limited due to a combination of the technology available at the time and the fact that we were focusing solely on food produced in the local area.”

“When we became the EURL for Fruits and Vegetables in 2006, our remit grew to include not only locally-grown produce but also imported goods from around the EU and further afield. This meant that we had to greatly increase the scope of our investigations, as many pesticides which are banned in the EU are still in use in the rest of the world.

Our role as an EURL is two-fold. Firstly, we are responsible for developing and validating the methods that will be used for pesticide testing across the laboratory network, with over 95 percent of these tests based on MS analysis.

Just as importantly, we undertake the proficiency testing for the official laboratories that perform the routine screening of produce, to ensure consistent and reliable results across the network. We have three types of proficiency tests. One, the ‘normal’ test where labs are sent a sample to identify and quantify a list of pesticides. Two, a ‘rapid turnaround’ test that only gives a lab 72 hours to respond. And three, a ‘special matrices’ test for complex foodstuffs such as baby food, which can cause problems for some laboratories.”

Amadeo continued: “Although we only test a very limited number of official samples ourselves, around 2,000 to 2,500 a year, it is essential that we are familiar with the instruments and methods that are used in the official laboratories, and so we have a large number of MS instruments from various manufacturers. We have used SCIEX systems in the lab for many years, and have always had a great experience using them.

We originally started with the API 3200™ System, which was a very good and particularly robust instrument; it can work 24 hours a day, seven days a week without any problems. This is particularly important for pesticide residue testing, as the laboratories tend to be located in more remote areas, so response times for on-site technical support are unavoidably slower than in big cities.

 As technology has advanced and new instruments have been launched onto the market, our EURL role means that we now have a large number of SCIEX systems, including a Triple Quad 4500 System, a Triple Quad 5500 System and a TripleTOF® 5600+ System.”

“The latest addition to our instrument pool is the X500R QTOF System, which we received a few months ago. This system is designed specifically for the kind of routine screening activities performed in our official laboratories and is both compact and robust. Based on our initial studies, which have focused on pesticides that relate specifically to the EU directive on baby foods (Directive 2006/141/EC), the X500R is very effective for high throughput testing.

We started with pesticides in baby food as this is a difficult matrix and the most stringent directive, requiring pesticide residues to be below 10 μg/kg. So far, we are easily achieving this level of sensitivity with this instrument, and the reproducibility is very good in terms of both mass accuracy and quantitative measurements. The measurement linearity is also very good, with no detectable saturation up to 500 μg/kg, beyond the normal linear range of our laboratory tests, making it very practical and convenient for routine testing.”

“Probably the most important aspect of this system, at least from our perspective, is the ability to work with SWATH® Acquisition, especially with difficult matrices.

When you analyze ‘easy’ samples, for example, lettuce or tomatoes grown locally, the number of active components is quite low. But when you look at fruits or vegetables, and especially herbs, from other parts of the world, the number of active components can be quite high, and SWATH is a fantastic tool to solve this problem. With difficult matrices, we will probably ionize a few thousand molecules with a full scan. If you compare that with MS/MS, then the number of ion fragments increases a lot, creating very complex chromatograms. This can lead to identification problems using traditional approaches, as the ion ratio can change due to background effects.

SWATH allows us to perform data independent acquisition with variable windows, and so we can move to 20 mass windows and produce very clean spectra with 10-12 data points, enough data for quantification. It is also very fast, making it ideally suited for high throughput applications, without compromising on sensitivity.”

Find out more about the EURL for Fruits and Vegetables >

This article is from the 2017 edition of the SCIEX VISION journal. You can download the full version of the journal which includes over 10 customer research stories. Download now >