Determination of Polycyclic Aromatic Hydrocarbons in Vegetables by Headspace SPME-GC

Moisture-sensitive metal-organic framework constructed from cobalt and 4-(4-pyridyl) benzoic acid for dispersive solid-phase extraction of polycyclic aromatic hydrocarbons in apple

A moisture-sensitive metal-organic framework Co^II (pybz)₂ ·2DMF was synthesized and applied as the adsorbent of dispersive solid-phase extraction. The structure changed after water treatment due to the fact that two chelate carboxylate groups on the skeleton were transformed to monodentate because of the coordination of water molecules. The material showed good adsorption for fluorene, phenanthrene, fluoranthene, and pyrene in water because of the π-π conjugation and π-complexation effects. Coupled with high-performance liquid chromatography, a dispersive solid-phase extraction method of determining the content of fluorene, phenanthrene, fluoranthene, and pyrene in apple samples was established after optimizing the extraction conditions. Methanol containing 4% acetic acid was used as the effective eluent. The linearities were 0.5-1000 μg/kg for fluorene, phenanthrene and 5-1000 μg/kg for fluoranthene, pyrene. The limits of detection were 0.06-0.6 μg/kg, and the recoveries were 94.4-116.4%. The method has a high sensitivity for the determination of four polycyclic aromatic hydrocarbons in apple samples.

Nano-hydroxyapatite/polyaniline composite as an efficient sorbent for sensitive determination of the polycyclic aromatic hydrocarbons in air by a needle trap device

Hydroxyapatite is a readily available, inexpensive, environmentally friendly adsorbent with high adsorption capacity. In this study, a polyaniline-doped nano-hydroxyapatite (PANI@HA) adsorbent was synthesized and employed in a needle trap device for the extraction of polycyclic aromatic hydrocarbons such as naphthalene, fluoranthene, benzo[a]anthracene, phenanthrene, and benzo[a]pyrene for the first time. The synthesized adsorbent was characterized by X-ray diffraction, field emission scanning electron microscopy, and Fourier-transform infrared spectroscopy analysis. Initially, effective variables such as the carryover effect, storage time, accuracy, and precision of the method were examined in the laboratory. The desorption conditions were optimized using the response surface methodology and central composite design methods. From the standpoint of quantitative parameters, the limit of detection and limit of quantitation were determined to be between 0.001 and 0.003 and 0.021 and 0.051 ng mL-1, respectively, which indicates the high sensitivity of the proposed method. Additionally, no significant changes were detected after storage of analytes inside the needle at 4 °C after 60 days. The results of this study also provide a high correlation between the results of sampling with needles containing PANI@HA and with XAD-2 adsorbent tubes (standard NIOSH 5115 method) (R 2 = 0.98). Finally, the proposed method was successfully employed in the extraction and determination of polycyclic aromatic hydrocarbons in field (real) samples. In general, it can be concluded that a needle packed with PANI@HA is a reliable and high-performance method for sampling polycyclic aromatic hydrocarbons compared to the NIOSH method.

Assessment of Foliar Uptake and Accumulation of Airborne Polyaromatic Hydrocarbons Under Laboratory Conditions

Urban horticulture and community gardening have become more and more popular in the past years, however, the risk of bioaccumulation of atmospheric polyaromatic hydrocarbons (PAHs) in vegetables grown in polluted areas cannot be neglected. In our study, the No. 227 OECD GUIDELINE FOR THE TESTING OF CHEMICALS: Terrestrial Plant Test: Vegetative Vigour Test was followed to assess foliar uptake of PAHs from aqueous extract of an urban aerosol. Using lettuce (Lactuca sativa) as a test organism, significant accumulation was experienced. The highest bioconcentration factors (BCFs) were experienced for naphthalene and for anthracene, pyrene and fluoranthene showed the lowest bioaccumulation potential. BCF of each PAH showed strong correlation with molecular weight. The standard protocol defined by the Guideline made it possible to assess bioaccumulation pattern under controlled laboratory conditions.

Polycyclic aromatic hydrocarbons in fruits and vegetables: Origin, analysis, and occurrence

Feed intake, for non-smokers, is the first route of contamination to polycyclic aromatic hydrocarbons (PAHs), which are potentially toxic compounds via ingestion. Investigations are focused on the presence of PAHs in fruits and vegetables. Transfer of PAHs can occur from air and soil during cultivation. They can also appear prior to consumption during storage, transport or cooking processes. Rather low amounts of PAHs are usually detected in raw fruits and vegetables. Quantities are between 0.01 and 0.5 μg kg^-1 (wet weight) for compounds classified as priority pollutants by the US Environmental Protection Agency (EPA). However, several studies point out that concentrations of some PAHs can exceed 0.5 μg kg^-1 wet weight in diverse fruits and vegetables and even reach 5 μg kg^-1. Amounts can be very different depending on the surrounding area of the crops, the aromatic hydrocarbon, or even the product itself. PAHs content is usually higher for products grown near roadways or in urban regions than in rural areas. Trace level of compounds such as phenanthrene, fluoranthene and pyrene have been found in quite every raw fruit and vegetable. Relative high amounts of lighter PAHs such as naphthalene, acenaphthylene, and acenaphthene have been found in some of them.

Distribution and Health Risk Assessment on Dietary Exposure of Polycyclic Aromatic Hydrocarbons in Vegetables in Nanjing, China

In a market basket study made in Nanjing, China, in which the most common consumed nine kinds of vegetables foodstuffs were sampled, the contents of 16 polycyclic aromatic hydrocarbons (PAHs) were analyzed using gas chromatography with mass spectrometer detector (GC-MS). The results showed that the total amount of 16 PAHs was within the range of 60.5~312 ng g−1 (wet weight). The ranking of total concentrations for different types of vegetables in decreasing order was leafy vegetable, fruit vegetable, and rhizome vegetable. Source analysis suggested that coal, oil, or other incomplete combustion of biomass mainly contributed to the concentration of PAHs. The margin of exposure (MOE) approach with age/gender group-specific daily dietary exposure level was used to estimate the carcinogenic risk. The calculated total mean MOE in the case of BaP and PAH4 (sum of BaA, CHR, BbF, and BaP) was 14960 and 7723, respectively, for local residents. In addition, the MOEs in PAH4 for some groups of both male and female were below the critical limit of 10 000 proposed by EFSA. Therefore, health effect owing to the consumption of vegetables on local residents needs high concern.

Determination of Polycyclic Aromatic Hydrocarbons in Wastewater by Single-Drop Microextraction Coupled to Capillary Gas Chromatography

This study describes an analytical method employing capillary gas chromatography (GC) using flame ionization detection (FID) that has been developed for the simultaneous determination of polycyclic aromatic hydrocarbons (PAHs) in wastewater, including naphthalene, 1-naphthol, 2-naphthol and anthracene. For this purpose, single-drop microextraction (SDME) was applied as a sample preparation technique. The SDME parameters such as types of extractants, volume of the microdroplet size, extraction time, stir rate and immersion depth of needle point were investigated and optimized. The method was linear in the ranges from 2.3 ×10-3to 70.0 μg·mL-1for naphthalene, 1-naphthol and anthracene, and 2.2 ×10-3to 50.0 μg·mL-1for 2-naphthol withR2≥ 0.9990. The SDME procedure allowed efficient recovery of the investigated PAHs ranging between 94 % and 104 % with a relative standard deviation (RSD) ≤4.2 for actual wastewater sampes spiked with 5, 10 and 20 μg·mL-1of PAHs, respectively. These results showed the potential of this technique for PAHs monitoring in wastewater samples. Furthermore, the investigated methods are simple, reliable, reproducible, and not expensive.