“Research indicates that Atmosphere Pressure Gas Chromatography (APGC) is a robust alternative technique that provides the selectivity and sensitivity needed for efficient and effective dioxin analysis. Advancements in analytical techniques such as APGC provide huge potential to the future of feed safety.”
Dr. Xiaomin Li
Institute of Quality Standard and Testing Technology for Agro Products (IQSTAP)
Dr. Xiaomin Li, Assistant Professor at the Institute of Quality Standard and Testing Technology for Agro Products (IQSTAP) in Beijing, China says that the institute is dedicated to achieving improvements of feed safety in China. Dr. Xiaomin Li reminds that as a result of several incidences, such as the melamine scandal in 2008, stricter regulations have been put in place but there is still a call for more complete feed regulations on safety and quality assurance in China. With its huge population, China is both a giant producer and market. “It’s a responsibility with worldwide implications, as China is a leading importer, producer, and consumer of animal feeds and feed ingredients, affecting food quality and safety around the globe”, Dr. Li points out, taking the Chinese reality into consideration.
Below is the interview with Dr. Li:
Can you tell us a bit about the work that you’re doing at the Institute of Quality Standard and Testing Technology for Agro Products?
The Institute of Quality Standard and Testing Technology for Agro Products (IQSTAP) in Beijing, China, is dedicated to achieving improvements of feed safety in China. It’s a responsibility with worldwide implications, as China is a leading importer, producer, and consumer of animal feeds and feed ingredients, affecting food quality and safety around the globe.
At IQSTAP, we focus on feed resource development and utilization, feed and animal product safety, ecological environment safety, and animal product quality. Researchers investigate all facets of the feed industry, but mainly focus on feed biotechnology, biochemical engineering and extraction, animal nutrition and feed science, feed processing technology, feed testing and safety evaluation, and feed economy and information.
Please explain the importance of feed analysis in China?
It has generally been believed for some time that Chinese governmental regulations are behind the current demand in the feed industry. As a result of several incidences, such as the melamine scandal in 20081, stricter regulations have been put in place but there is still a call for more complete feed regulations on safety and quality assurance in China. Laboratories such as ours at IQSTAP are continuously developing analytical capabilities with new methods and innovative technology, to help the industry achieve this.
What are dioxins and why is it important to do ultra-trace toxin analysis of feeds?
Polychlorinated dibenzo-para-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are toxic organic pollutants that take a long time to break down once they are present in the environment. These toxins are found throughout the world, and they accumulate in the food chain, mainly in the fatty tissue of animals.
Tightening regulations on contaminants in feed and food have sparked the need for greater sensitivity from analytical techniques like gas chromatography mass spectrometry (GC-MS). Additionally, reducing the injected volume of samples has been shown to minimize matrix effects and the contamination on instrumentation – two factors that directly affect dioxin analysis.
Monitoring the presence of these contaminants is vitally important for food safety, particularly because PCDDs and PCDFs are highly toxic and can cause cancer, reproductive and developmental problems, damage to the immune system, and hormone interference.
Their presence in the global food chain has led to increased interest in detecting and quantifying these contaminants in feed and food supplies. Most human exposure to dioxins is through food, mainly meat and dairy products, fish and shellfish. Due to the bio-accumulative nature of these compounds, it is essential to monitor them at ultra-trace levels in food and environmental samples.
There have been a number of cases across Europe in the past few decades of dioxins entering the human food chain through contaminated animal feed. For example, the Irish pork crisis in 2008 was caused by dioxin contamination of animal feed, where the cost of cattle and pig culling was over €4 million and compensation for loss of revenue was around €200 million2. In 2011, imports of eggs and meat were banned from Germany to China when 4,700 German farms were affected by animal feed contaminated with dioxin3.
What kind of data are you looking to extract?
The established presence of PCDDs and PCDFs in the food chain makes ongoing monitoring of these contaminants in feed and food essential to ensure that the levels do not exceed the allowable concentration, which has sparked scientific interest in improving dioxin analysis methods.
Eight scientists at the Dioxin Testing Laboratory are continually working to advance the analysis of dioxins by developing new methods for detection and quantification of contaminants in feed and food samples. We use the international gold standard method for detecting PCDDs and PCDFs – isotope dilution high-resolution gas chromatography (HRGC) coupled with high-resolution magnetic mass spectrometry (HRMS). The European Commission has established that GC-MS/MS may be used as a confirmatory method for PCDD and PCDF detection.
Can you explain the pressures from regulations/compliance factors?
China implemented a revised regulatory and registration system for imported feed and feed additives in 2015. The World Health Organization (WHO) has conducted human-based risk assessments, setting toxic equivalent factors for these compounds. Dioxins are restricted internationally under the Stockholm Convention on Persistent Organic Pollutants4. Additionally, the European Union has limited or prohibited the use of many of these compounds and has set standards on acceptable levels in feed and food supplies.
These regulations are continually reviewed and updated as new research becomes available. The established presence of PCDDs and PCDFs in the food chain makes ongoing monitoring of these contaminants in feed and food essential to ensure that the levels do not exceed the allowable concentration, which has sparked scientific interest in improving dioxin analysis methods.
Have you faced any limitations in your work?
Traditionally, the determination of persistent organic pollutants used electron ionization (EI) for fragmenting the molecules and generating charged ions for detection. But some of the compounds of interest for us were not suitable for “hard” ionization analysis such as EI. That’s because the EI technique sometimes gave rise to identical ions for different compounds, so its selectivity is limited. At the same time, the EI technique can make it difficult to see the whole molecule, and it can result in the same fragment for compounds with different numbers of bromine atoms. That presented our team with the challenge to overcome the limitations of EI for feed and food safety analysis.
The IQSTAP Dioxin Testing Laboratory is dedicated to improving its methodology for analyzing the most toxic PCDDs and PCDFs. It’s a mission that faces several complications – including the need for sensitivity and accuracy, as well as matrix interference.
The uniqueness of dioxin analysis means that each dioxin laboratory is faced with the complexity of the sample matrix, the effective purification of the sample, and the quasi-deterministic quantitative problem of the target compound.
We are continually working to advance the analysis of dioxins by developing new methods for detection and quantification of contaminants in feed and food samples.
How do you think developments in analytical techniques will influence the future of feed security?
Detection and quantification of contaminants in feed is vital to reduce dioxin exposure to animals and humans, and alleviate potential repercussions. Research undertaken by IQSTAP indicates that Atmosphere Pressure Gas Chromatography (APGC) is a robust alternative technique that provides the selectivity and sensitivity needed for efficient and effective dioxin analysis.
Advancements in analytical techniques such as APGC provide huge potential to the future of food safety, moving the industry a step closer to achieving worldwide compliance with regulatory limits.
Why do you use Atmospheric Pressure Gas Chromatography (APGC)?
The use of APGC enables us to improve the detection and quantification of toxins in feed and food, and we are now poised to share these developments with the greater scientific community.
APGC is a very sensitive detection system for the accurate determination of dioxins and furans at regulatory levels. We work closely with other scientific researchers and testing organizations, and personnel from other laboratories often visit us to study our methodology and we introduce them to the methods and experiences that we have found work better.
There has been a surge of research in this area in recent years. For example, scientists in Spain have used APGC for monitoring pollutant concentration in food to ensure it meets regulatory requirements of the European Union5-7. Similarly, a laboratory in the Netherlands is able to expand the number of pesticides it is able to detect in food and feeds using APGC, to meet the growing requirement of manufacturers to test their products8.
Why did you adopt APGC above other techniques?
The IQSTAP team found several significant advantages to APGC when compared with traditional dioxin analysis methodology:
• Soft ionization: The APGC soft ionization method is suitable for the analysis of many easily degradable compounds. That’s particularly helpful with dioxin analysis, where El has significant limitations. Reduced fragmentation can give higher sensitivity and specificity, therefore simplifying pre-cursor ion selection in MS/MS analyses. With the APCI interface, a soft and reproducible ionization is favored in GC, typically the protonated molecule and/or the molecular ion is the base peak of the spectrum in most cases.
• Easy LC to GC changeover: Since APGC is not a vacuum technique, equilibration time between techniques is kept to a minimum. This means the analysis can be tailored to demands, maximizing up-time and instrument utilization. It also gives researchers the widest possible coverage from analyses.
• Ease of use: The easy-to-use interface of APGC instrumentation, such as that from Waters, reduces the need for training, as well as speeds up the implementation process in the laboratory – two significant benefits in the dioxin analysis field. That makes APGC fit easily into our workflow and speeds up productivity.
What results have you achieved with APGC?
With its ability to detect contaminant limits at ultra-trace levels, APGC enabled us to achieve compliance with regulatory limits on the presence and quantity of toxic PCDDs and PCDFs. The increased sensitivity of APGC coupled with MS enabled the Dioxin Testing Laboratory researchers to quantify and confirm trace contaminants at even lower levels in the most complex samples. Additionally, because they could inject less sample matrix, the APGC technique reduced the effects of contamination on the instrumentation – and therefore increased uptime.
We also found the analysis of feed and food samples by APGC allows for improved selectivity when generating multiple reaction monitoring (MRM) transitions in comparison to the significant fragmentation experienced with EI gas chromatography. Operating the GC system at atmospheric pressure provides increased scope for ionization mode optimization – namely charge and proton transfer.
Our Dioxin Testing Laboratory researchers have found APGC is a robust and sensitive technique for analyzing dioxins in feed and food samples, and they see the potential for expanded use in the field9. We believe incorporating this innovative technique holds great advances for food security both to detect pollutants and monitor their levels to ensure they meet the specifications regulated by the European Union – as well as future standards that develop over time in other countries around the world.
We plan to continue our work to improve the analysis of other persistent organic pollutants using APGC by researching the capabilities of APGC and its possibilities for their work.
APGC has provided us with new ideas for scientific research. It offers an alternative to traditional GC-MS for dioxin analysis, providing the speed and sensitivity we need.
We also suggest you to read our previous article titled "What determines the nutritional value of animal products is feed".