Determination of PAHs in cereal-based baby food by GC-MS | EKOL

Determination of PAHs in cereal-based baby food by GC-MS

Determination of polycyclic aromatic hydrocarbons in cereal-based baby food by gas chromatography-mass spectrometry

The occurrence of polycyclic aromatic hydrocarbons (PAHs) in cereal-based food is the result of different food preparation methods (e. g. roasting or drying) and the bioaccumulation in the oily seeds. The carcinogenetic and mutagenic activity of PAHs, and the low legal limit of these compounds in infant food (controlled by regulation 835/2011/EU, a maximum of 1 ng/g for the total of benzo(a)pyrene, benz(a)anthracene, benzo(b)fluoranthene and chrysene) make it important to develop selective and efficient sample preparation method. It has higher priority in the work with baby foods, since the PAHs can have higher effect on infants. At the same time it is complicated to measure PAHs from the baby foods, because of their high fat content, and the fats and target compounds have the same lipophilic nature....

The most critical step of the sample preparation method is the separation of PAHs from oils and fats. The removal of lipophilic substances is important in order to minimize the contamination load of the chromatographic system, and reach high sensitivity (and 1 ng/g quantification limit) for PAHs. The separation of PAHs was carried out with a three-step liquid-liquid extraction method with hexane and dimethyl sulfoxide (DMSO). The procedure is based on the interaction of the sulfur atom in DMSO and the PAHs aromatic π electron system. This results in different partitioning for PAHs and lipids in the DMSO - n-hexane system....

The extraction of PAHs (and aliphatic materials) from powdered biscuit was carried out with the n-hexane. The n-hexane was washed with distillated water and extracted with DMSO. Fat content remained in the n-hexane, while DMSO (with the target compounds) was separated. After back-extraction of PAHs into n-hexane, the sample was evaporated and analyzed with GC-MS.

The described sample preparation method is capable to separate PAHs from fatty acids.

Author: Noémi Petrovics, Chemistry Msc student