Polycyclic aromatic hydrocarbons (PAHs), of which benzo[a]pyrene is the most commonly studied and measured, are formed by the incomplete combustion of organic matter. They are widely distributed in the environment and human exposure to them is unavoidable. A number of them, such as benzo[a]pyrene, are carcinogenic and mutagenic, and they are widely believed to make a substantial contribution to the overall burden of cancer in humans. Their presence in the environment is reflected in their presence at detectable levels in many types of uncooked food. In addition, cooking processes can generate PAHs in food. PAHs can also be formed during the curing and processing of raw food prior to cooking. Several studies have been carried out to determine the levels of exposure to PAHs from representative human diets, and the proportion of the overall burden of environmental exposure to PAHs that is attributable to the diet. In most cases, it is concluded that diet is the major source of human exposure to PAHs. The major dietary sources of PAHs are cereals and vegetables, rather than meat, except where there is high consumption of meat cooked over an open flame. More recently, biomonitoring procedures have been developed to assess human exposure to PAHs and these have also indicated that diet is a major source of exposure. Exposure to nitro-PAHs through food consumption appears to be very low.

Polycyclic aromatic hydrocarbons in the diet.

Derivatization reactions for the determination of amines by gas chromatography and their applications in environmental analysis.

Polycyclic aromatic hydrocarbons in smoked fish: a critical review

Contamination of the environment by pharmaceuticals, quinolones among them, is recognized as an emerging issue of concern to scientists and the public. Literature on the environmental analysis of quinolones has addressed a very small percentage of these compounds, and the analytical methods developed to determine them are very scarce. By contrast, a large number of methods have been proposed for their analysis in food, which has classically been considered the source of these residues for human beings. Although both matrices, food and environment, differ, most of the information obtained from one field can be applied to the other. However, to be able to do this, there is need for critical discussion about how analytical determination is carried out in each case. This review summarizes the most relevant issues that condition the analogies and the contrasts between food and environmental matrices in the analysis of quinolones. We describe and compare the target analytes and their relevant levels. We also critically review the approaches to extraction (e.g., solvent extraction (SE), pressurized liquid extraction (PLE) and solid-phase extraction (SPE)), depending on the sample characteristics. We also detail the main analytical techniques (e.g., liquid chromatography (LC) and capillary electrophoresis (CE) combined with UV, fluorescence (FLD) and mass spectrometry (MS), immunoassays and biosensors) used to identify and to quantify quinolone residues in both matrices. We present an updated overview of the recent uses and future prospects for the different analytical methods employed in food and environmental samples.

Analytical strategies to determine quinolone residues in food and the environment

Analysis of quinolone residues in edible animal products

A simple and accurate analytical method for determination of polycyclic aromatic hydrocarbons (PAHs) in fish and shellfish is presented, which is considered to be useful for routine analyses and for screening purposes. The procedure involves alkaline digestion, extraction with n-hexane, silica gel column chromatography, and liquid chromatographic (LC) determination with fluorometric detection. During development of the analytical method for determination of PAHs, it was found that benzo[a]pyrene, a representative PAH, was decomposed easily by the analytical procedure, and this tendency was investigated for the experimental conditions used. Benzo[a]pyrene was decomposed by the coexistence of alkaline conditions, light, and oxygen; by peroxides in aged ethyl ether; and by oxygen when absorbed on silica gel. Thus, to obtain good recoveries and precise analytical results, these decomposition conditions must be avoided. The following precautions are recommended: protection from light through all analytical steps; addition of Na2S to alkaline digestion mixture as an antioxidant; complete removal of peroxides from ethyl ether just before use; quick column chromatography on silica gel; and prevention of air from contact with adsorbent. When this simple method was applied to fish and shellfish samples, very good recoveries of PAHs from fortified fish samples were obtained, and no serious interferences were observed in fish and shellfish extracts.

Liquid chromatographic determination of polycyclic aromatic hydrocarbons in fish and shellfish.

Determination of N-nitrosodimethylamine in fish products using gas chromatography with nitrogen-phosphorus detection.

Gas chromatographic-mass spectrometric determination of macrolide antibiotics in beef and pork using single ion monitoring

A simple liquid chromatographic (LC) method is described for the determination of free and added niacin and niacinamide in meats. A sample is homogenized and extracted with water, and the water extract is centrifuged, deproteinized with zinc hydroxide, and filtered first through a fluted paper and then through a microporous filter. The filtrate is subjected to liquid chromatography with UV detection at 263 nm. Different ion-pair systems are needed for the measurement of niacin and niacinamide on a reverse phase column. Methanol-water (1 + 9) containing 5mM tetrabutyl ammonium ion is used to separate niacin. Water containing 10mM heptane sulfonic acid is recommended for niacinamide. Recoveries (CV,%) are 104.8% (2.9%) for niacin and 96.3% (2.7%) for niacinamide at a 10 mg/100 g fortification level. Detection limit is 1 mg/100 g sample for niacin and niacinamide.

Keigo Takatsuki

Papers

Liquid chromatographic determination of polycyclic aromatic hydrocarbons in fish and shellfish.

Determination of N-nitrosodimethylamine in fish products using gas chromatography with nitrogen-phosphorus detection.

Gas chromatographic-mass spectrometric determination of macrolide antibiotics in beef and pork using single ion monitoring

Liquid Chromatographic Determination of Free and Added Niacin and Niacinamide in Beef and Pork

Gas Chromatographic/Mass Spectrometric Determinationof Oxolinic, Nalidixic, and Piromidic Acid in Fish