Phase distribution of polycyclic aromatic hydrocarbons and their oxygenated and nitrated derivatives in the ambient air of a Brazilian urban area☆.

Air quality in large cities has worsened in recent years as a consequence people's health is directly affected. Among the toxic compounds released to environmental air are polycyclic aromatic hydrocarbons (PAHs), nitrated PAHs (nitro-PAHs), and oxygenated PAHs (oxy-PAHs). Performant methods to analyze these compounds is necessary to enable adequate monitoring of air quality. Thus, this manuscript presents the development of a highly sensitive method to analyze PAHs, nitro-PAHs, and oxy-PAHs collected from ambient air (PM2.5) and the gas phase for a period of one year in the urban area of Belo Horizonte, Brazil. PAHs and their derivatives were extracted by cold fiber solid phase microextraction (CF-SPME) and analyzed by gas chromatography coupled to mass spectrometry (GC/MS). The proposed method allows simultaneous analysis of 16 PAHs, nitro-PAHs and oxy-PAHs, presenting very good limits of detection and quantification, as well as appropriate precision and recovery. The results obtained for the period of one year allowed different studies. The compounds collected simultaneously from gas and particulate phase showed that total concentration of 16 PAHs were higher in the gas phase than in the particulate. On the other hand, nitro-PAHs and oxy-PAHs presented similar concentration in gas and particulate phases. The potential carcinogenicity of PAHs relative to benzo[a]pyrene showed benzo[a]pyrene equivalents of 0.49 ng m-3. The estimated risk of lifetime lung cancer was 5 × 10-5. Principal component analysis and diagnostic ratio was applied for source distribution indicating that burning of gasoline, diesel and biomass accounted for the PAHs profile in ambient air samples.

Determination of polycyclic aromatic hydrocarbons and their nitrated and oxygenated derivatives in coffee brews using an efficient cold fiber-solid phase microextraction and gas chromatography mass spectrometry method.

Polycyclic aromatic hydrocarbons (PAHs) are food contaminants; besides, their oxygenated (oxy-PAHs) and nitrated (nitro-PAHs) derivatives have also been detected in some foods. This is worrying because these derivatives may be more toxic than PAHs. This study presents a new method for the determination of PAHs and their oxygenated and nitrated derivatives in coffee brew. The analytes were extracted by cold fiber solid phase microextraction (CF-SPME) with analysis by gas chromatography/mass spectrometry. The developed method presented good precision with intra-assay and inter-assay, ranged from 4.5 to 16.4%, and from 9.8 to 19.8%, respectively. Recovery ranged from 82.1 to96.3% and linearity showed good adjustment presenting determination coefficients (R2) from 0.980 to 0.999. The limits of quantification ranged from 0.025 to 0.224 µg L-1. The proposed method is simple, versatile, allows simultaneous extraction of PAHs, nitrated and oxygenated derivatives and was successfully applied to the analysis of commercial coffee samples. Benzo(k)fluoranthene, benzo(b)fluoranthene, pyrene, acenaphthylene and acenaphthene are the most abundant PAHs found in samples. In addition, 5,12-naphthacenequinone was the most abundant oxy-PAH and 1-nitropyrene was the most abundant nitro-PAH.

Efficient extraction method using magnetic carbon nanotubes to analyze cocaine and benzoylecgonine in breast milk by GC/MS.

AIM: The increasing use of cocaine (COC) during breastfeeding has led to growing concern about exposure of infants. Therefore, to study this exposure, a new method to analyze COC and benzoylecgonine in breast milk was developed. METHODOLOGY: A new extraction method was used for the first time to analyze COC and its major metabolite, benzoylecgonine, in breast milk using magnetic carbon nanotubes partially doped with nitrogen. RESULTS: The calibration curves were linear in the range 5.0-180.0 ng ml-1. The limit of quantification was 5.0 ng ml-1. Coefficients of variation were between 3.2 and 13.9%. Recovery was between 89.6 and 99.2%. CONCLUSION: The proposed method is simple, efficient and suitable to determine analytes in breast milk.