BUNSEKI KAGAKU Abstracts

The quality of water has a significant influence on instrumental analyses. In the microanalysis of trace elements or organisms by ICPMS, ion chromatography, HPLC or LC/MS, remaining materials in the blank water should be decreased to less than ppt. Today we can easily obtain ultra-pure water of such a high quality for analytical instruments using a high-performance water purifier. However, we often make mistakes in the usage of ultra-pure water, and also in the operation of a water purifier. The manner to use ultra-pure water is quite important, as well as the performance of the water purifier. It is necessary to make a standard method to use ultra-pure water for trace elements or organisms analysis.

Because electrospray is based on electrochemical reactions taking place at the tip of a capillary, the detection efficiency for the analytes increases by downsizing of the electrospray system, i.e., electyrospray → nanoelectrospray. Recently, we have developed a probe electrospray ionization (PESI) that uses a fine solid needle. In this system, the probe needle moves up and down along the vertical axis by a motor-driven system. At the lowest position, the tip of the needle touched the surface of the sample and a small amount of liquid is picked up by the needle. At the highest position, the loaded sample is electrosprayed. PESI can be applied to direct and real-time analyses for any wet real-world samples without any special sample preparations. The fundamentals and application of PESI are summarized.

The Japan Society for Analytical Chemistry has developed a series of certified reference materials (CRMs) for the X-ray fluorescence analysis of Ag, Cu, Pb, and Cd in lead-free solder alloys, named JSAC 0131-0134. In order to prevent oxidations within the process of fusion, the surfaces of samples were covered by a reducing agent. Furthermore, in order to make a fine metallographic structure, the samples at fusion were quickly cooled by water. By using these new methods, homogeneous samples could be prepared. The concentrations of the four elements ranged from 0.488 to 3.91 mass% for Ag, 0.102 to 1.01 mass% for Cu, 13.9 to 2007 mg kg⁻¹ for Pb, and 0(<3) to 1530 mg kg⁻¹ for Cd. The certified values were evaluated by statistical analyses of the results of an interlaboratory comparison study. This study was supported by participants from 20 laboratories for obtaining data. The z scores in the robust method were applied to a statistical analysis. The certified uncertainties were determined at confidence levels of 95%. These products are the first CRMs in Japan for the determination of hazardous elements and major elements in lead-free solder alloys.

We examined the reliability of calibration for the determination of each compound in solution mixtures of volatile organic compounds (VOCs) that contained a smaller number of VOCs by the 23 VOCs mixture standard solution supplied based on Japan Calibration Service System (JCSS). We prepared 16 VOCs mixture standard solution, 12 VOCs mixture standard solution and 10 VOCs mixture standard solution by a gravimetric method, and each compound in these was determined using the 23 VOCs mixture standard solution for calibration. A comparison of the gravimetric value and the measured value for the concentration of each compound was performed based on the En value. The En value of every compound in those mixture standard solutions was equal to or less than 1, indicating that the 23 VOCs mixture standard solution can be used for calibration. A storage stability test for six months was carried out, where the standard solutions were subdivided into 30 ampoules and stored at 5°C. The concentration change of all the solutions tested for six months was within −1.2%∼0.5%. Homogeneity tests for the subdivided ampoules were also carried out. The F-test (F₀<F, critical value of F for α = 5%) indicated an insignificant difference in the homogeneity test.

Kits for an LED-base colorimeter and a potentiometer for ion-selective electrodes, dedicated to high school or undergraduate student experiments, have been developed. These kits are intended not only to provide experience chemical analysis, but also for manufacturing analytical instruments for themselves. A micro-controller was used to simplify the electronic circuit, to reduce costs, and to provide practical analytical performance to those kits. Both kits can be built within 2 hours and at expenses of less than 10 thousand yen. After the time and easiness for assembly and the analytical performance were evaluated with prototypes, print circuit boards for them were manufactured. These kits were used in lectures for high school students, high school teachers and undergraduate students. Almost all students were able to complete the kit within a given time, and could apply it to analytical experiments.

In order to prevent disasters of the explosive accidents involving methane gas associated with hot springs in Hyogo Prefecture, we examined the analysis methods of the methane, and investigated the distribution of methane in the Prefecture. We examined the analysis methods of methane by combustible gas detectors on-site and gas chromatography (GC) at a laboratory. In this study, a catalytic combustion detector was used. Results obtained from the detector method and from the GC method were compared. While measuring by a detector, when the oxygen concentration was insufficient, the deviation from the set level and the measured level was significant. However, our study revealed that by supplying oxygen through an air suction port on the detector, the influence of a low oxygen concentration could greatly be decreased. On the other hand, a measurement by the GC method was not influenced by the oxygen concentration. Methane gas levels at 104 hot spring sources in Hyogo prefecture were measured by a method combining the use of a detector and GC. The results showed that the concentration of methane was in the range between N.D. and 1560%LEL (78vol%), while the oxygen concentration was in the range from 0.01% to 17.0%. Furthermore, at 21% of the targeted hot spring sources, the methane gas concentration was found to be in excess of the standard level.

The Japan Society for Analytical Chemistry has developed coal ash certified reference materials (CRMs), JSAC 0521 and 0522, whose concentrations of principal constituents (Si, Al, Ca, Mg, Fe, K, Na, P, Sr, Ti, C and S), trace constituents (As, B, Be, Cd, Co, Cr, Cu, F, Hg, Mn, Ni, Pb, Se, V and Zn) and ignition loss were certified. JSAC 0521 and JSAC 0522 were prepared from Japanese coal ash and foreign coal ash, respectively. CRMs were checked according to the method of JSAC CRM QM002, and the homogeneities were shown to be excellent. Certified values were obtained from statistical analyses of the results of interlaboratory comparisons for coal ashes. Twenty one laboratories participated in this study, but the results for Cd and F were obtained from 11 and 6 laboratories, respectively. Precise results for Cd (11 laboratories) were obtained only by inductively coupled plasma-mass spectrometry (ICP-MS), atomic absorption spectrophotometry and inductively coupled plasma-atomic emission spectrometry (ICP-AES) at a wavelength of 228.798 nm, because the line is not interfered in the presence of Fe and/or Pt. The results for F proved that, statistically, there is a difference in their extraction efficiency between distillation and pyrohydrolysis. Higher results were obtained by pyrohydrolysis than those by distillation ; a recovery of F was incomplete by one-time distillation. Only the results by pyrohydrolysis (6 laboratories) were employed in this study.

Because antimony (Sb) compounds possess useful applications, they have been widely used as functional materials. Consequently, many literatures report an extraordinary enrichment of Sb in environmental samples. By focusing on similarities in the elemental composition, particle size distribution, and microscopic images between the ambient APM and several potential sources, we have investigated the predominant sources of Sb in airborne particulate matter (APM) in Japan. The distribution of the Sb concentration in size-classified ambient APM showed a bimodal profile in which peaks were found in fine (0.6 μm) and coarse (4.0 μm) fractions. Elemental ratios, particle sizes, and microscopic images observed in the coarse APM fractions were found to be in good agreement with those of brake abrasion dust. On the other hand, in the fine APM fractions, fly ash originating from waste incineration was identified as being the most probable source of Sb. A chemical mass balance analysis was performed to determine the effects of the emission sources of Sb, and it was revealed that waste fly ash and brake abrasion dust were the dominant sources of Sb in the finer and coarser fractions of APM, respectively. This thesis provides important clues for understanding the cycles and fates of Sb in the environment.