Dioxins Contamination Analysis

Dioxins are a group of organic chemicals that have a wide range of halogenated aromatic compounds and known as persistent environmental pollutants (POP).

Figure 1. Foods products associated with dioxin contamination

Dioxins widely exist in the environment. The burning process of wood, fuels and coal can produce dioxins. Dioxins are very persistent and not easy to break down in the environment. They are considered as environmental pollutant which remain in the sediments and soils with high levels for long time. Water and air generally contain less levels of dioxins. The production of dioxins is reduced in the industry by many countries. But they can still be formed through a byproduct of other industrial process which are not easy to be completely eliminated.

Foods can be contaminated by dioxins from the environment. Foods that specifically have high risk of dioxins contamination include fish, meat and dairy products. Dioxins get into the foods mainly through food chain and are stored in the animal fats. They can bioaccumulate in the food chain due to their lipophilic characteristics. The emission of dioxins into the food chain is strictly controlled.

Dioxins are highly toxic and have shown in animal studies to cause damage to the immune and reproduction system. They can also break the balance of hormones and contribute to cancer. Dioxins have been classified by International Agency for Research on Cancer (IARC) as a "known human carcinogen". Dioxins are not easy to metabolize and stay in the human body for a long time. It can take years to reduce to the half of the original level.

The European Commission specified the maximum levels for dioxins in a variety types of foods. The contamination limits were set as 0.1 pg/g for infant and young children foods, 1.5 pg/g for mixed animal fats, 2.5 pg/g for eggs and dairy products, and 3.5 pg/g for fish and fishery products. Low levels of dioxins need to be detected.

The procedure for the analysis of dioxins in foods includes sample preparation and extraction, column clean-ups, and detection/quantification. We control sample preparation factors and have extensive steps for sample clean-up. We have expertise in the sample preparation of a variety types of food matrices. The sample preparation has significant effect on the accuracy of the level measured in the food samples.

The commonly analyzed group of dioxins is polychlorinated dibenzo-p-dioxins (PCDDs). The most toxic one is 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). We offer accurate and validated analytical methods that have been widely applied in the determination of dioxins in food samples to meet customers' needs.

Gas chromatographs coupled with mass spectrometer (GC-MS)

GC-MS is used in EPA method 613 for the analysis of 2,3,7,8-TCDD. The limit of detection for 2,3,7,8-TCDD is 0.002 μg/L.

High resolution gas chromatographs coupled with high resolution mass spectrometer (HRGC-HRMS)

HRGC/HRMS is used in EPA method 1613 for the analysis of dioxins. It is capable to analyze a number of specific dioxin isomers.

We also maintain high quality assurance for the analysis. The recovery of internal standard, the use of blanks and spikes is monitored for each batch of analysis.