Pressurized liquid extraction (PLE) is considered an advanced extraction technique developed in the mid-1990s with the aim of saving time and reducing solvent with respect to traditional extraction processes. It is commonly used with solid and semi-solid samples and employs solvent extraction at elevated temperatures and pressures, always below the respective critical points, to maintain the solvent in a liquid state throughout the extraction procedure. The use of these particular pressure and temperature conditions changes the physicochemical properties of the extraction solvent, allowing easier and deeper penetration into the matrix to be extracted. Furthermore, the possibility to combine the extraction and clean-up steps by including a layer of an adsorbent retaining interfering compounds directly in the PLE extraction cells makes this technique extremely versatile and selective. After providing a background on the PLE technique and parameters to be optimized, the present review focuses on recent applications (published in the past 10 years) in the field of food contaminants. In particular, applications related to the extraction of environmental and processing contaminants, pesticides, residues of veterinary drugs, mycotoxins, parabens, ethyl carbamate, and fatty acid esters of 3-monochloro-1,2-propanediol and 2-monochloro-1,3-propanediol from different food matrices were considered.
12 June 2009 in Food Additives & Contaminants: Part A
Smoking and/or grilling, when carried out with traditional methods involving direct contact with wood combustion fumes, is responsible for high contamination levels with carcinogenic polycyclic aromatic hydrocarbons (PAHs). The aim of this work was to investigate the PAH content of different smoked or grilled meat and fish products commonly consumed in Nigeria. A rapid method involving microwave-assisted saponification and simultaneous extraction followed by solid-phase extraction (SPE), high-performance liquid chromatography (HPLC) separation and spectrofluorometric detection was employed. Samples that were smoked or grilled using traditional systems, which use a wood fire, were heavily contaminated with benzo[a]pyrene (BaP) at levels ranging from 2.4 to 31.2 µg kg−1 wet weight. Considerably lower contamination levels were found in samples smoked or grilled in the laboratory using a charcoal fire (BaP from 0.7 to 2.8 µg kg−1 wet weight). The health risk associated with a daily consumption of 100 g of these products was also evaluated using the margin of exposure (MOE) approach. MOE values lower than 10,000 were obtained for all smoked/grilled commercial samples, indicating a potential concern for consumer health.