Polycyclic Aromatic Hydrocarbons Contamination Analysis

Polycyclic aromatic hydrocarbons (PAHs) are a class of over 100 different organic compounds which have multiple condensed benzene rings composed by carbon and hydrogen. They aromatic rings may carry additional substituents.

Figure 1. Chemical structure of PAHs and related foods

PAHs naturally occur in the environment such as gasoline, coal and crude oil. They are primarily generated during the incomplete combustion of these carbon-based organic matter (coal, garbage, oil, and wood). Then PAHs can form small particles and maintain in the air. Some PAHs can be also found from water and soil. Food raw ingredients may be contaminated by PAHs that are present in soil, air or water from the environment. The levels of PAHs contamination in unprocessed food can reflect the nearby overall environment condition.

The major source for PAHs to get into food is the formation of PAHs as a consequence of certain food processing and cooking at high temperatures. PAHs can be formed during high-temperature cooking (such as grilling, roasting, and frying) and processing (such as smoking and drying) of foods.

PAHs are harmful to human health and considered to have potential to cause cancer and a number of PAHs are considered as genotoxic carcinogens. There are several studies that have reported the biological and mutagenic effects of PAHs. Other PAHs which are not defined as carcinogens may also act as synergists. Therefore, the monitoring of PAHs in food products has been strongly recommended by different regulation agencies.

The need for a reliable analysis of PAHs concentrations in foods is increasing. Analytical laboratories play an important role in the analysis of PAHs and their derivatives in food with adequate methodologies and techniques. The European Commission specified the maximum levels for PAHs in a variety types of foods. The contamination limits were set as 1.0 μg/kg (ppb) for infant formula and young children foods, 2.0 μg/kg (ppb) for oils and fats, and 5.0 μg/kg (ppb) for smoked meat and fishery products.

The extraction of PAHs from food matrices typically include a series of steps like liquid-liquid extraction and clean-up by column chromatography (or solid-phase extraction) for liquid samples. Solid matrices are extracted using sonication devices with suitable solvents. The approaches may vary depending on different food matrices. We also have expertise in sample preparation (extraction and clean-up) of a variety types of food matrices, such as fatty matrices.

PAHs are globally monitored after the extraction from food, biological and environmental samples using approved analytical approaches by certain regulation organizations or agencies. We offer accurate and validated analytical methods that have been widely applied in the determination of PAHs in food samples to meet customers' needs.

High performance liquid chromatography (HPLC)

HPLC is used in EPA method 610 which is a frequently used method for PAHs analysis. It is more sensitive, reproducible and specific.

Gas chromatography coupled with mass spectrometry (GC-MS)

GC-MS is used in EPA method 625, also frequently used for the separation and detection of PAHs.

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.