Chemical markers for the characterization of bioaerosol

Bioaerosol is commonly defined as aerosolized particles, with a biological origin, spread into the air by a variety of abiotic and biotic mechanisms. The size of bioaerosol can range from several nanometers to a few hundred micrometres in aerodynamic diameter. Examples of bioaerosols include fungal and bacterial spores/cells, fungal hyphae, pollen, viruses and amoebae, algae, lichen, archaea, aggregates of these particles, and fragments of larger organisms including leaf litter, skin scales, animal and plant debris. Metabolites and excreta are also included in this topic. In these last years the knowledge about indoor and occupational bioaerosol exposure and related diseases has significantly increased. Biological particles have been linked to mucous membrane irritation, allergy, asthma, inflammatory lung diseases, hypersensitivity pneumonitis and so on . The use of biomarkers as a tool for the determination of bioaerosol has often been suggested. The basis of this approach is that bioaerosol components contain chemical compounds that can be used as markers of larger and/or bioactive structures. The main objective of our research is the identification and quantitation of dipicolinic and muramic acids, ergosterol, poliols, amino acids and proteins as markers of bacterial, fungal spores/cells and generic bioaerosol, in both indoor and outdoor airborne particulate matter. To achieve this purpose, methods of extraction and analysis by chromatographic techniques coupled to mass spectrometry of different classes of compounds from particulate matter of different size (ultrafine, fine and coarse), collected in proper sampling campaigns, have been developed

A liquid chromatography tandem mass spectrometry method for simultaneous analysis of 46 atmospheric particulate-phase persistent organic pollutants and comparison with gas chromatography/mass spectrometry,

A novel multi-analyte method for the simultaneous determination of 46 compounds of environmental concern, most of them belonging to the category of persistent organic pollutants, was developed using high-performance liquid chromatography and the results were compared to those obtained by gas chromatography. This study was performed in perspective of a cumulative exposure assessment of substances of health concern in environments where high levels, relatively to airborne particulate matter, can be found. The target compounds included polychlorinated biphenyls, brominated flame-retardants and derivatives of polycyclic aromatic hydrocarbons. The multi-analyte method was evaluated in air particulate matter in terms of reproducibility, linearity, recovery, limits of detection and quantification and matrix effect. The recovery was above 70% for all the analytes, whereas limits of quantification ranged between 23 and 390 pg.m(-3) in liquid chromatography and less than ten times in gas chromatography-mass spectrometry. Matrix effect was generally negligible for both the techniques, except the case of the detection of oxygenated derivatives of polycyclic aromatic hydrocarbons by gas chromatography

Liquid chromatography tandem mass spectrometry analysis of synthetic coccidiostats in eggs

Coccidiostats are synthetic drugs administered to animals, especially to poultry, to cure coccidiosis. In this paper, we present a selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to analyze residues of five synthetic coccidiostats in eggs: clazuril, diclazuril, robenidine, nicarbazin, toltrazuril and its two metabolites. The extraction efficiency was evaluated by testing several solvents, pH, different volumes and time of extraction. The clean-up procedures were optimized using different solid phase extraction cartridges and different eluants. The chromatographic separation was achieved in reversed phase using a gradient of 0.1% formic acid in water and acetonitrile, whereas the MS detection was performed in negative electrospray ionization (ESI) for all the analytes, except for the robenidine. The developed method has been validated according to Commission Decision 2002/657/CE. The validation parameters, as linearity, precision, recovery, specificity, decision limit (CC alpha), detection capability (CC beta), and robustness have been determined. The proposed method resulted simple, fast, and suitable for screening and confirmation purposes

Determination of pesticides in the respirable fraction of airborne particulate matter by high-performance liquid chromatography–tandem mass spectrometry

Potential harmful effects of pesticides include risks to human health of workers involved in the wet spray application in cultivated areas. Inhalation exposure depends on several factors including pesticide concentrations in the respirable fraction of airborne particulate matter (PM4). To ensure a high level of protection, the use of tractors with cabins provides protection against dust, aerosols, and vapors. Since tractors not providing maximum protection are still in use, PM4 was sampled during spreading operations in agricultural fields inside and outside tractor cabins. Sample preparation technique based on accelerated solvent extraction and solid-phase extraction cleanup was optimized before analysis of nine pesticides in PM4. Meptyldinocap, deltamethrin, myclobutanil, fluopyram, methoxyfenozide, dimethomorph, fluopicolide, cyflufenamid, and metrafenone were simultaneously determined by high-performance liquid chromatography–electrospray ionization–tandem mass spectrometry (HPLC–ESI–MS–MS). The results demonstrated the efficacy of the tractor cabs used in the sampling sites. © 2017 Taylor & Francis

Determination of Sugar Content in Commercial Fruit Juices by Refractometric, Volumetric and Chromatographic Methods

In this paper several approaches are discussed for the direct analysis of the main sugars in different fruit juices. Refractometry, thin layer chromatography, volumetric analysis and high performance liquid chromatography with refractive index detector were tested and the results compared, discussing the advantages and disadvantages of each of them. Whereas the first method gives generically indications on the whole content of sugar and it doesn't require any prior manipulation of the sample, thin layer chromatography is useful only for qualitative purpose, on the other hand the third method, after removal of interferences, makes possible the determination of the reducing and not reducing sugar, and the last one allows the qualitative and quantitative determination of the saccharides singularly. It's very important to have not only knowledge about the chemical analysis of carbohydrates and their physicochemical properties, but especially how the methods can be used in product development for benefit of the public. In the wide range of options for the determination of the mono and disaccharides in beverages, the approach selected must be robust, accurate, powerful and reproducible

Determination of the main bioaerosol components using chemical markers by liquid chromatography–tandem mass spectrometry

This work is part of an extensive research project aimed at the determination and characterization of bioaerosol with a multidisciplinary approach. In this context, one of the main objectives of the project has been the development of a comprehensive analytical method for the determination of different chemical biomarkers of the bioaerosol, by liquid chromatography coupled with tandem mass spectrometry. The following biomarkers have been considered, and correlated to specific components of bioaerosol as unambiguous indicators: • ergosterol fungal components • chlorophylls, phytosterols (stigmasterol and b-sitosterol), -tocoferol vegetable cells and algae • cholesterol animal cells, vegetable cells and algae. • dipicolinic acid bacterial spores • muramic and meso-2,6-diaminopimelic acid bacterial cells To verify the method, to find diagnostic ratios and to calculate the appropriate conversion factors, fungal spores, bacterial cells and spores, and algae of known species, commonly airborne, were analysed. The material was subjected to freezing and de-freezing cycles, followed by extraction, hydrolysis and purification of the biomarkers. The chromatographic separation of the bacterial biomarkers was achieved by using a polymeric column, based on Hydrophilic Liquid Interaction with the electrospray ionization mass spectrometric detection, whereas sterols and chlorophylls were separated by a reversed phase column, coupled to atmospheric pressure chemical ionization – tandem mass spectrometer. The optimized method was applied to environmental particulate matter sampled in an outdoor site. Bacterial and fungal content was compared to the results obtained from the classical direct viable counting method in the sampled particulate matte

Toxic organic contaminants in airborne particles: levels, potential sources and risk assessment

In the last years, many studies have focused on risk assessment of exposure of workers to airborne particulate matter (PM). Several studies indicate a strong correlation between PM and adverse health outcomes, as a function of particle size. In the last years, the study of atmospheric particulate matter has focused more on particles less than 10 m or 2.5 m in diameter; however, recent studies identify in particles less than 0.1 m the main responsibility for negative cardiovascular effects. The present paper deals with the determination of 66 organic compounds belonging to six different classes of persistent organic pollutants (POPs) in the ultrafine, fine and coarse fractions of PM (PM < 0.1 m; 0.1 < PM < 2.5 mand 2.5 < PM < 10 m) collected in three outdoor workplaces and in an urban outdoor area. Data obtained were analyzed with principal component analysis (PCA), in order to underline possible correlation between sites and classes of pollutants and characteristic emission sources. Emission source studies are, in fact, a valuable tool for both identifying the type of emission source and estimating the strength of each contamination source, as useful indicator of environment healthiness. Moreover, both carcinogenic and non-carcinogenic risks were determined in order to estimate human health risk associated to study sites. Risk analysis was carried out evaluating the contribution of pollutant distribution in PM size fractions for all the sites. The results highlighted significant differences between the sites and specific sources of pollutants related to work activities were identified. In all the sites and for all the size fractions of PM both carcinogenic and non-carcinogenic risk values were below acceptable and safe levels of risks recommended by the regulatory agencies

Development of a repressible mycobacterial promoter system based on two transcriptional repressors

Tightly regulated gene expression systems represent invaluable tools for studying gene function and for the validation of drug targets in bacteria. While several regulated bacterial promoters have been characterized, few of them have been successfully used in mycobacteria. In this article we describe the development of a novel repressible promoter system effective in both fast- and slow-growing mycobacteria based on two chromosomally encoded repressors, dependent on tetracycline (TetR) and pristinamycin (Pip), respectively. This uniqueness results in high versatility and stringency. Using this method we were able to obtain an ftsZ conditional mutant in Mycobacterium smegmatis and a fadD32 conditional mutant in Mycobacterium tuberculosis, confirming their essentiality for bacterial growth in vitro. This repressible promoter system could also be exploited to regulate gene expression during M. tuberculosis intracellular growt