We have applied laser-induced breakdown spectroscopy to quantitative analysis of colloidal and particulate iron in water. A coaxial sample flow apparatus developed in our previous work, which allowed us to control the atmosphere of laser-induced plasma, was used. Using sequential laser pulses from two Q-switched Nd:YAG lasers as excitation sources, the FeO(OH) concentration in the tens of ppb range was determined with an optimum interval between two laser pulses and an optimum delay time of a detector gate from the second pulse. The detection limit of Fe decreased substantially using two sequential laser pulse excitations:  the 0.6 ppm limit of single pulse excitation to 16 ppb with sequential pulse excitation. The effects of the second laser pulse on the plasma emission were studied. The concentration of iron in fine particles in boiler water sampled from a commercially operated thermal power plant has been determined successfully by this method. The results show the capability of laser-induced breakdown spectroscopy in determining suspended colloidal and particulate impurities in a simple and quick way.

Fullerenes are the carbon materials that only 60 or more carbon atoms are covalently bounded. Since such greatly unique materials were discovered, many researches of fullerenes have been carried out. On the other hand, the unique carbon soot (CS) is yielded at production of fullerene, but it is not really investigated. However, we think that the application of CS is extremely important from the perspective of fullerene research and of market expansion. In this study, we prepared the composites by adding CS to styrene block copolymer (SBC), and then investigated the additional effect by measuring dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC) and tensile properties. It was found that tensile modulus and heat-aging resistance of the SBC improved by adding CS.

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