BUNSEKI KAGAKU Abstracts

We succeeded to fabricate a two-dimensional array of gold nanoparticles with high-ordering by using the surface plasmon excitation of gold nanoparticles for enhancing the repulsive force and controlling the aggregation through the process of fabrication. From SEM observations and spectroscopic measurements, we evaluated the order of the two-dimensional array of gold nanoparticles while taking account of particle isolation. Moreover, the high-ordering of the two-dimensional array provides higher sensitivity and higher reproducibility of Raman measurements. From these results, it is expected that our fabricated two-dimensional array of gold nanoparticles will lead to applications for a molecular sensor.

Chemical process with multiphase fluids, such as typified by an extraction process, plays an important role in various fields of chemistry. Extraction using multiphase microlfows in microchannels has attracted attention for over a decade because multiphase microflows can shorten the extraction time by several orders of magnitude as compared to the case of conventional extraction. The physical properties of multiphase microflows are different from those of conventional fluids. Multiphase microflows show various flow patterns, such as parallel microflow, segmented microflow, microemulsions, and annular microflow. Fluid control techniques based on the physical properties of microfluids have been developed in order to control such microflows, and applications utilizing those multiphase microflows have been reported. In this paper, the fundamental physical properties of multiphase microflows, fluid control methods, and microextraction processes are introduced.

A graphite oxide-containing molecularly imprinted polymer (GO-MIP) was prepared by using pyridoxine as a template molecule. The adsorption behavior of pyridoxine to GO-MIP was studied based on Scatchard analysis. The fluorescence of pyridoxine was quenched on the GO-MIP. In contrast, GO-MIP did not exhibit quenching to the fluorescence of non-templated fluorescein. The fluorescence of pyridoxine was quenched more effectively by GO-MIP than by GO, confirming that the fluorescence was quenched through the selective binding of pyridoxine to the imprinted polymer.

For observation and analysis with SEM, EPMA, or SIMS, aerosol particles were collected on a flat substrate in an “aerosol impactor”. However, these particles, especially large particles, tended to form clusters at the center of the impaction point. Therefore, the analysis of an individual particle at the center became difficult. To overcome this problem, our previously developed small impactor was modified. In this modified impactor, a collection substrate was placed on an X—Y stage to scan the impaction point with in a 5 mm×4 mm area during sampling, by using a DC motor, a cam, and a shaft. Any overlapping of the scanning lines for each scanning frame can be reduced by converting the ratio of the X and Y speeds into decimals. Upon comparing SEM images of particles collected using a conventional impactor and those using the above-mentioned impactor, it was confirmed that the evenness of the number of particles per unit area as well as the particle size distribution were enhanced.

Since nuclear magnetic resonance (NMR) spectroscopy obtains a quantitative value on the basis of a nucleus, the quantitative NMR technique does not require an identical standard. For this reason, it is expected to be a universal quantitative method. Recently, the quantitative NMR method was adopted also as a regulating method. However, the quantification using an NMR requires a high-resolution balance in the sample preparation for accurate weighing of the mass of samples. This is the biggest problems to disseminate a quantitative NMR as a generally used method. In this paper, we discuss the quantitative NMR method using the internal standard solution in order to resolve the problem. We examined two methods of sample preparation: the gravimetric method and the volumetric method. The influence of the preparation method and condition was evaluated using a standard solution. Additionally, some organizations have used this method to measure the purity of a high-purity reference material for the validation of this standard solution method. The accuracy of the results was evaluated using an internal standard solution by the volumetric method, and measured at 1% or less.

The sequence of investigation was analogyed in order to improve the accuracy of the BOD test. Bacteria were found in a phosphate buffer solution (A) and a magnesium sulfate solution (B). These bacteria were not expected to exist; however, by leaving these bacteria in the solutions, the dilution water less than 0.2 mg L⁻¹ of the BOD, and could be prepared by being incubated in a dark place at 20°C for 7 days. Commercial inocula were not sufficiently active to satisfy the JIS criteria of 220±10 mg L⁻¹ in the glucose-glutamic acid standard check. However, a seed solution that is able to obtain the result of 220±10 mg L⁻¹ in the standard check has been gained by incubating a sample that has similar properties to one from river water or a natural lake in a condition like that in river water or a natural lake. In the incubation, a glucose-glutamic standard solution was added to the seed solution, and it was incubated for several days in a dark place at 20°C under a condition containing abundant oxygen in it.

There have been some cases concerning the low recovery of tin when samples of alcoholic beverages were determined by a dry ashing method. A series of experiments were subjected to reveal the causes of losses. It was confirmed that the chief causes were volatilization and insolubilization. We found that there were high risks of evaporation of tin, as SnCl₄, when it was dried over a boiling bath with HCl. It was effective for reducing the losses of tin by adding ammonium oxalate to the ash, and drying with HCl after ashing at 500°C. According to this procedure, an insoluble form of tin could dilute with 1 mol L⁻¹ HCl. The addition of magnesium nitrate was also effective to improve the recovery of containing low-salt samples. It was impossible in this survey to recommend a single method for the ashing for all types of alcoholic beverage samples. We showed two alternative procedures, depending upon whether the sample contains much or little salt and organic materials.

A simple analytical method was developed for the determination of ^113mCd in treated wastewater arising from the Advanced Liquid Processing System (ALPS) at the Fukushima-1 nuclear power plant. Cadmium in wastewater containing sea salt was effectively separated by an anion-exchange procedure. It was found that 98.6% of the Cd was recovered by the present procedure from a sample solution of 2 M HCl. Since a radioactivity standard solution of ^113mCd was difficult to purchase from venders, the beta-ray counting efficiency for ^113mCd was estimated using ¹⁴C, ³⁶Cl, and ⁹⁹Tc standard solutions. The minimum detectable activity was calculated to be 0.0011 Bq mL⁻¹. The present analytical method would be well-suited for a rapid and simple determination of ^113mCd in wastewater treated by ALPS.

The second and third glaze events in Shikoku region were observed to have arisen during the early morning in March 9/2012 and January 14/2013, respectively. In order to obtain information about the concentrations of chemical constituents in glaze, one of the samples was collected from the summit of Mt. Kajigamori (ALT. 1400 m), where is the watershed protection forest of Riv. Yoshinogawa is located. The concentrations of major soluble ions and toxic elements, such as Cd and Pb, were analyzed. High concentrations of nss-SO₄²⁻ and Pb were observed with the back-trajectory over Middle and North China. The residues in the glaze were analyzed by a SEM-EDX technique. In the residue, various components of small spherical particulate were also found, indicating the presence of various origins of the fly-ash, including coal burning with the effect of long-range transport.