Persistent organic pollutants (POPs) are chemical substances that are of worldwide concern. As a result of industrial activity, POPs are widespread in the environment and persist for many years after formation. Exposure to POPs can be harmful to living organisms, including humans, because POPs produce a toxic effect at very low concentrations and bio-accumulate in fatty body tissues for long periods. Dietary exposure to POPs is of great concern due to their ability to bio-magnify up the food chain. Like any other contaminant, food contamination incidents involving POPs can fast become global news, damage brands and negatively affect international trade.

Controlling POPs in the food chain is critical to ensuring environmental and human health. Due to concerns about these substances, the Stockholm Convention on POPs (an international treaty administered by the United Nations Environment Program to eradicate or severely restrict POPs use) has been ratified by more than 160 nations to protect human health, wildlife and the environment.[1] Continuous monitoring of the presence of POPs in food, food additives and the environment is a key aspect to controlling exposure. Strong legislation with strict testing requirements has been established by organizations such as U.S. FDA, U.S. EPA and the EU Commission.

Some of the POPs present in humans that are of greatest concern are polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). These two groups of chemicals are collectively referred to as dioxins and are known to be highly toxic, cause reproductive and developmental problems, damage the immune system, interfere with hormones and also cause cancer.[2] The majority of exposure to these chemicals usually occurs through diet.[3]

Our corporate mission was the driving force behind the formation of the Thermo Fisher Scientific POPs Center of Excellence. Established in 2011, this Center was created to support laboratories with the task of researching and monitoring POPs in food and the environment. The Center is focused on enabling high productivity, providing valuable solutions for some of the most challenging POPs determinations and consolidating the POPs resources and expertise offered by Thermo Fisher.

Located in Bremen, Germany, the POPs Center supports customers and associates internationally as a:

•    Reference for POPs analysis

•    Point for access to POPs methodology using Thermo Scientific products

•    Resource for collaborative projects on the latest instrumentation

•    Knowledge hub for Thermo Scientific product users who are working in POPs analysis

•    Partner to industry and government labs to improve the quality and efficiency of POPs monitoring

Members of the POPs Center of Excellence team have worked within the area of POPs analysis for many years, both within Thermo Fisher and also with a variety of organizations including government institutions for regulatory monitoring, universities researching POPs and high-throughput contract testing labs. This brings the Center a wealth of experience and expertise while it also enables a high level of collaboration with outside organizations, especially with respect to the latest technologies applicable for monitoring POPs.

Supporting Regulatory Change for Safer Food
For many years, EU legislation has stipulated that only GC-MS instrumentation that can provide high resolution (R = 10,000) accurate mass for PCDDs/PCDFs  and dioxin-like (dl)-PCBs analysis are applicable for reporting confirmatory results for dioxins in food and feed samples.[4] This requirement is driven by the need for these compounds to be monitored at ultratrace levels in food and feed due to concerns about their toxic effects in humans at very low concentrations and their ability to accumulate in fatty body tissues for long periods. The combination of complex sample matrices (food and feed) and ultratrace quantitation requirements (low pg/g) means that very high sensitivity and selectivity is required throughout the method to ensure the total toxicity of the sample is determined accurately.

The gold standard to provide the required performance for this analytical challenge is GC-MS on magnetic sector instruments (GC-HRMS) such as the Thermo Scientific™ DFS™ High-Resolution GC-MS system. These systems provide the ultimate performance to measure dioxins and other compounds very accurately and precisely at extremely low concentrations in a variety of complex matrices. They are especially suited to provide data for background level studies and official maximum level control in food and feed.

In recent years, there has been a growing interest in GC-MS/MS techniques as a means to supplement GC-HRMS systems in the official control of POPs in the food chain. Recently, European reference laboratories undertook a project to look at GC-MS/MS in the context of current legislation and the Thermo Fisher Scientific POPs Center supported their efforts. Dr. Martin Rose of the UK National Reference Laboratory (NRL) for Contaminants in Food and Feed at The Food and Environmental Research Agency (FERA) comments, “Thermo Fisher has helped us as an NRL to evaluate the suitability of using GC-MS/MS for official food and feed control of dioxins. We wanted to establish whether or not this technique was at a stage where it could meet the highly demanding analytical criteria required for dioxins analysis, which previously allowed only HRMS to be used as a confirmatory technique.”

In addition to investigating the suitability of GC-MS/MS as a confirmatory technique, EU reference laboratories were charged with making a recommendation to the EU Commission about amending the regulations and defining analytical performance criteria associated with the analysis.  The POPs Center collaborated in the investigation and presentation of the data to the scientific community for discussion. In some cases, the Thermo Scientific™ TSQ Quantum XLS Ultra™ GC-MS/MS was provided to the reference laboratories along with support and consultation from the POPs Center team, especially in training and setting up the instrument methods. The help of the Center facilitated the development of a rich data set on a variety of matrices and helped accelerate the working group’s ability to engage in the scientific debate and discussion. In fact, the POPs Center also helped encourage the discussions by establishing their own meetings that took place during dioxin conferences in San Antonio, Brussels and Australia. In addition, the popular Recent Advances in POPs Analysis symposium organized by the Center is running into its 9th occurrence and has seen presentations from leading researchers and industry experts on this subject and many more associated with POPs analysis. Dr. Rose states, “The POPs Center symposia are high quality international events with the same scientific caliber (but a more narrow analytical focus) as the wider, more prestigious international conferences that focus on POPs research.  They are very well organized and take place in carefully chosen locations to help make them very memorable events.” Some of the findings of the Reference Laboratories working group were also presented at Dioxins 2012 in Cairns, Australia.[5]

The result of the investigative work in dioxins and PCBs was a recommendation to update the legislation in the EU. The new legislation will allow for the use of GC triple quadrupole MS in addition to GC-HRMS for the official control of food and feed samples. According to Dr. Rose, “Being able to use MS/MS will open up the possibility of undertaking dioxins analysis to a much larger number of food and feed control laboratories who do not have access to HRMS.  The more laboratories undertaking this analysis, the more analysis and control will be undertaken, resulting in a safer food supply.”

What’s Next?
There has been a marked increase in the desire of many food producers and ingredient manufacturers to monitor their own processes extremely closely in order to protect consumers from exposure to POPs. As new regulations appear, the POPs Center team will focus on supporting organizations that interact with the food chain to ensure they have access to the best analytical technologies and methods available. In addition, the Center will be working with researchers to develop new, efficient methods using the latest technologies available to monitor new POPs that are still being classified.

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3.    European Food Safety Authority; Results of the monitoring of dioxin levels in food and feed. EFSA Journal 2010; 8(3):1385 [36 pp.]. doi:10.2903/j.efsa.2010.1385. Available online:
4.    Commission Regulation (EC) No 152/2009 of 27 January 2009 (OJ L 54, 26.2.2009, p. 1–130), Commission Regulation (EC) No 1883/2006 of 19 December 2006 (OJ L 364, 20.12.2006, p. 32–43)
5.    Anaytical Criteria for use of MS/MS for Determination of Dioxins and Dionxin-like PCBs in Feed and Food: Kotz A et al. Organohalogen Compounds Vol. 74, 156-159 (2012)