Validation and field application of tailor-made nitrogen dioxide passive samplers

This study describes the validation and field application of new tailor-made passive samplers for nitrogen dioxide measurements. These samplers consist of polypropylene diffusion tubes containing glass fiber filters impregnated with 20 % triethanolamine. The tube was constructed from locally made material. The sampler is simple, lightweight, cheap, easy to use and suitable for simultaneous and multipoint measurements. Nitrogen dioxide concentrations obtained from the passive samplers were strongly correlated with chemiluminescence analyzer (r = 0.924). The nitrogen dioxide measurements by the passive samplers have been recorded at 20 sampling sites in Chiang Mai City, Thailand, once a month (3 days of exposure) from November 2007 to April 2008. The sampling sites were located across the city in alignment with the major wind direction. The highest nitrogen dioxide concentrations (28.1–45.1 ppbv) were found in the urban areas with high level of traffic density and human activity. Meteorological conditions, i.e., wind direction/speed and precipitation, were considered for their influence on nitrogen dioxide concentrations. Due to a calm wind occurring during the sampling, its direction had, therefore, no significant effect on nitrogen dioxide concentrations collected from the different locations. However, the mean nitrogen dioxide concentrations were higher at the downwind sites than at the upwind locations. Unlike wind, rain precipitation obviously affected pollutant concentration levels. In regard to the spatial and temporal variations of nitrogen dioxide concentrations in the study sites, it was deduced that their levels were much more affected by local activities, such as traffic density and biomass burning, rather than meteorological factors

Validation and field application of tailor-made nitrogen dioxide passive samplers

This study describes the validation and field application of new tailor-made passive samplers for nitrogen dioxide measurements. These samplers consist of polypropylene diffusion tubes containing glass fiber filters impregnated with 20 % triethanolamine. The tube was constructed from locally made material. The sampler is simple, lightweight, cheap, easy to use and suitable for simultaneous and multipoint measurements. Nitrogen dioxide concentrations obtained from the passive samplers were strongly correlated with chemiluminescence analyzer (r = 0.924). The nitrogen dioxide measurements by the passive samplers have been recorded at 20 sampling sites in Chiang Mai City, Thailand, once a month (3 days of exposure) from November 2007 to April 2008. The sampling sites were located across the city in alignment with the major wind direction. The highest nitrogen dioxide concentrations (28.1–45.1 ppbv) were found in the urban areas with high level of traffic density and human activity. Meteorological conditions, i.e., wind direction/speed and precipitation, were considered for their influence on nitrogen dioxide concentrations. Due to a calm wind occurring during the sampling, its direction had, therefore, no significant effect on nitrogen dioxide concentrations collected from the different locations. However, the mean nitrogen dioxide concentrations were higher at the downwind sites than at the upwind locations. Unlike wind, rain precipitation obviously affected pollutant concentration levels. In regard to the spatial and temporal variations of nitrogen dioxide concentrations in the study sites, it was deduced that their levels were much more affected by local activities, such as traffic density and biomass burning, rather than meteorological factors

Facile synthesis of boronic acid-functionalized nanocarriers for glucose-triggered caffeic acid release

In this study, boronic acid-functionalized methacrylate-based nanoparticles were synthesized via surfactant-free emulsion polymerization in one pot. Uniform (polydispersity index < 0.05) sub-100 nm nanoparticles were obtained. The changes of average hydrodynamic diameter and polydispersity index of nanoparticles against boronic acid content in total monomer and acetone percentage in the solvent mixture were investigated. Polymerization kinetics in terms of monomer conversion rate was monitored by gravimetric method. The nanoparticles were characterized by scanning electron microscopy and dynamic light scattering. The boron content in the nanoparticles was confirmed by electron-dispersive X-ray spectroscopy. Further, the nanoparticles were combined with caffeic acid. Caffeic acid carrying nanoparticles were titrated against glucose or fructose in which caffeic acid is released by the displacement reaction in a controlled manner. The displacement of caffeic acid and glucose was monitored by UV-visible spectral change. Furthermore, in vitro biocompatibility of nanoparticles was tested in NIH-3T3 cells, which resulted no significant toxicity effect on the cells.Selcuk University Scientific Research Fund (S.U. BAP)Selcuk University [12201077]; TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [112M096, COST TD1004]This work was supported by Selcuk University Scientific Research Fund (S.U. BAP No. 12201077) and TUBITAK (Project No.112M096, COST TD1004). The authors are grateful to Advanced Technology Research and Application Center of Selcuk University for their kind help regarding with analysis studies (SEM, EDX, DLS, UV-Vis). The authors thank to Dr. Pembegul UYAR for providing 3T3 cells as a kind gift and her valuable guidance and to Huseyin Sakalak for his help in experimental studies