[Anthropogenic VOC emission inventory and contribution from industrial sources in Ningbo].

Ningbo is an important industrial city in eastern China and is also the economic center in the south wing of the Yangtze River Delta (YRD). Recently, the VOC emissions from the local industrial activities and its effects on both the regional air quality and people's health were getting more and more attention. The anthropogenic VOC emission inventory of Ningbo in 2010 was established with collecting comprehensive activity data of anthropogenic sources. Furthermore, the industrial sectors were studied and the significant industries were identified with their contribution quantified. The result shows that the amount of anthropogenic VOC emission in Ningbo in 2010 is 176 kt. Industry, transportation and residential source are the most important VOC anthropogenic sources in Ningbo, which accounted for 62.0%, 17.2% and 15.5% respectively. Synthetic materials manufacturing and refined petroleum products manufacturing are the most important VOC emitting industries, which contributed 18.6% and 13.1% of the total VOC amount respectively, signifying the influence of these two industries to the VOC emissions in Ningbo.

A rapid and sensitive colorimetric assay method for Co2+ based on the modified Au nanoparticles (NPs): understanding the involved interactions from experiments and simulations.

We previously reported a colorimetric assay method for Co(2+) based on the thioglycolic acid (TGA) functionalized hexadecyl trimethyl ammonium bromide (CTAB) modified Au NPs. However, the detection limit of 3×10(-7) M was still higher than that of the sanitary standard for drinking water (6.8×10(-8) M). In addition, the interactions between the modifier and Au NPs, and between the modifier-Au NPs and Co(2+) remain to be clarified and confirmed. Thus, in the present study, the modified Au NPs solution was dialyzed and its detection limit was optimized to be 5×10(-10) M. The interactions between the modifier and Au NPs, and between the modifier-Au NPs and Co(2+) were investigated in both experimental characterizations and theoretical calculations, consistently confirming that the Au NPs were modified by the negatively charged anions of [SCH(2)CO(2)](2-) through Au-S bonds and Co(2+) was recognized by the modifier-Au NPs through Co-O chelate bonds. The results of X-ray photoelectron spectroscopy (XPS) suggest that there were no chemical bonds formed between CTAB and Co(2+). Moreover, the colorimetric assay of Co(2+) using the modified Au NPs has been proved to be a rapid, very sensitive and highly selective method. The validation of the method was carried out by analysis of a certified reference material, GSBZ 50030-94.