New technique detects food contaminants

A NEW TECHNIQUE developed by researchers at the University Institute of Pesticides and Waters (IUPA) of the Universitat Jaume I de Castellón (UJI) can be used to detect and quantify potentially harmful contaminants in food samples.

The method, which uses atmospheric-pressure chemical ionization (APCI), can detect emerging pollutants more effectively and features a detection threshold of 10 to 50 times lower. It is more sensitive and accurate, and offers greater selectivity.

The technique, which has already been used in pesticides, dioxins and other pollutants, can be used to monitor levels of toxic compounds such as brominated flame retardants (BFRs) in marine products such as tuna fish and prawns. BFRs compounds are widely used in many products, including TVs, smartphones, furniture and plastic to reduce flammability. These toxic compounds are often released into the sea by factories and are therefore present in many foods of marine origin.

Pollutants ingested by fish and shellfish remain stored in the fats and may therefore be transferred to humans upon consumption of marine products. Because these pollutants are lipophilic substances, they cannot be excreted and therefore stay in our bodies, according to UJI researcher Carlos Sales. Pollutants have, in fact, been detected in breast milk, although at low levels so they pose no immediate health risk. Nevertheless, high doses of these pollutants can cause health problems such as cancer, endocrine disruption and neurological disorders.

It is therefore essential to ensure these compounds do not exceed acceptable limits in foodstuffs. The European Union has undertaken several actions to limit or prohibit the use of many such compounds.

The new technique is hoped to benefit food monitoring and safety, as detection of harmful contaminant concentrations in foodstuffs can be a potential cause for recall. It can also help ensure compliance with international standards such as those implemented by the European Union.

Another advantage is the potential drop in monitoring costs. The technique requires just half of the materials needed by traditional approaches. Further, it analyses pollutants at much lower concentrations.

The traditional detection method for BFRs and other persistent organic pollutants (POPs), according to Sales, uses electron ionization (EI) to fragment the molecules and charge the ions so that they can be detected. Besides limited selectivity due to the generation of identical ions for different compounds, this method shows the same fragment appearing for compounds with different numbers of bromine atoms and does not make it possible to see the whole molecule.

“With the APCI method, instead of directly ionising the molecules, we charge a gas (nitrogen), which collides with the molecules we want to see, leaving them ionised. In other words, the molecule is charged through collision, rather than by direct electrical discharge, meaning that it does break; this is what we mean when we talk about soft ionization. It is a more sensitive and selective technique because, if we have the whole molecule, we can more confidently ascertain whether there are contaminants in the sample and at what levels," Sales stated.

The methodology developed by the IUPA researchers, led by Dr. Félix Hernández, optimises the monitoring of compounds in food and environmental samples. It forms part of the research line led by Dr. Tania Portolés, researcher at the Universitat Jaume I with more than 10 years of experience in APCI.

Journal Reference: Carlos Sales, Tania Portolés, Juan Vicente Sancho, Esteban Abad, Manuela Ábalos, Jordi Sauló, Heidelore Fiedler, Belén Gómara, Joaquim Beltrán. Potential of gas chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry for screening and quantification of hexabromocyclododecane. Analytical and Bioanalytical Chemistry, January 2016, Volume 408, Issue 2, pp 449-459

Asociación RUVID. "Innovative technique to detect harmful food contaminants." ScienceDaily. www.sciencedaily.com/releases/2016/06/160601114317.htm (accessed August 12, 2016).