In routine analysis by inductively coupled plasma-optical emission spectrometry (ICP-OES), non-spectral interference cannot be neglected. Non-spectral interference has been classified into physical, chemical, ionization and excitation types by H. Shao et. al. In these types of interference, it is said that chemical interference can scarcely exist. In the case of rhodium, however, when perchloric acid was added to rhodium compounds formed with nitric acid in a solution, and nitric acid was added to rhodium compounds formed with perchloric acid in a solution, the rhodium compounds did not reach an equilibrium state to react with acids also added after about 40 days. Consequently, based on calculations with the F test and Student's t test to the rhodium emission intensities from the rhodium compounds, it was understood to be chemical interference. Although the coefficients of various types of chemical interference were less than 1 per cent, they cannot be neglected to obtain the most accurate analytical results.

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The composition of an anionic surfactant, α-sulfo fatty acid methyl ester was analysed by capillary electrophoresis (CE) and high-performance liquid chromatograhy (HPLC). HPLC separations were carried out by a reversed phase mode, an anion exchange mode and an ion chromatographic mode. In the CE method, it was possible to measure sodium 2-sulfonato fatty acid methyl ester (α-SF · Na) and disodium 2-sulfonato fatty acid (α-SF · 2Na) by using 10 mM-naphthalenesulfonate (pH 9)/acetonitrile (7 : 3) as the carrier electrolyte. Methyl sodium sulfate and sodium sulfate can be measured by using 5 mM-chromate (pH 8) solution containing 2 mM-cetyltrimethylammonium bromide as the carrier electrolyte. When the identical sample was analysed by HPLC and CE method, the quantitative value almost agreed with each other, and the reproducibility was also equivalent (relative standard deviation is 0.5∼8.6%). The CE method can determine all components quantitatively, and it separates all components within 30 minutes by the use of automated instrument. Then the CE method is preferable for process control.

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When a fission track method was applied to the melted or fused surface of some roof tiles collected at about 500 m from the hypocenter in the Nagasaki atomic bomb area, star-like fission tracks on the muscovite detector were revealed after neutron irradiation of the sample assembly in a reactor. These results offer certain evidence that micro-particles containing fissile nuclides of atomic-bomb origin remain on the roof tile surface. The Pu-contents in some remnant particles were evaluated to be 0.72∼5.7 × 10⁷ atoms from the star-like track analysis. Additionally, shortening of the track lengths suggested the existence of particles in slightly deeper sites from the tile surface. Subsequently, the accumulated γ-dose on some roof tiles, which were exposed at about 700 m from the hypocenter of the atomic bomb in Hiroshima, was evaluated from a blue thermoluminescence (TL) measurement of quartz extracts by a regeneration method. After correcting naturally accumulated doses within the roof tile, the retrospective dose amounted to 13.0 Gy, which was derived from the atomic bomb explosion. Furthermore, the exposed temperature on the surface of the Nagasaki roof tile was estimated to be beyond 1100°C based on TL color images, compared with the thermally annealed inner parts. From these results, hot particle remnants from the atomic-bomb were confirmed to be comprised of materials with a higher melting temperature than the fused temperature of the roof tile surface beyond 1100°C.

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A simple and rapid method of X-ray fluorescence spectrometry (XRF) was developed for the determination of carbon in lake sediments. Lake sediments were converted to thin-layer specimens as follows. After a powdered sample of 1.0∼2.0 mg with particle sizes of 3∼5 μm was dispersed in water by ultrasonication (US) for 10 seconds, the suspension was filtered off through a silica fiber filter. The dispersion procedures of powdered samples in water by US gave good recoveries for carbon in lake sediments. Standard samples for a calibration curve were prepared in the same manner using certified reference materials (LKSD-1, LKSD-2, JLK-1) of the lake sediments. Measurements of the carbon Kα intensities of thin-layer specimens (104∼208 μg/cm²) were achieved by an XRF equipped with synthetic multilayers (RX60) as the analyzing crystal without any matrix corrections. A good linear relationship was recognized for carbon in the range of 0∼0.22 mg. The detection limit was 2 μg (0.2 μg/cm²), which corresponds to 0.2% and 0.1% as the contents in lake sediments for sample amounts of 1.0 mg and 2.0 mg, respectively. The method was applied to sediments from Lake Kawaguchi and its spiked samples. The analytical results showed reasonable precisions of 2.2∼3.8% (RSD). The present method can be applied to sediments with ranges of carbon contents of 0∼22% and 0∼11% for sample amounts of 1.0 mg and 2.0 mg, respectively, and successfully used for paleo-environment analysis.

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The determination of the concentration of a tumor antigen, α-fetoprotein (AFP), by an antigen-antibody reaction was made using a surface plasmon resonance (SPR) sensor. The antibody AFP (anti-AFP) was immobilized on a gold film of a sensor chip with fatty acids having a mercapto group (HS(CH₂)nCOOH, n=2, 10). The fatty acid (n=10) gave a higher sensitivity for the measurement of AFP. After immobilizing the anti-AFP on the sensor chip under optimum conditions, the detection limit (0.60 ng/ml) was found to be equivalent to that in an enzyme immunoassay (EIA), and no interference was observed while measuring of AFP in a serum. Since the measurement using the SPR sensor is simple and rapid (less than 2 min), it is applicable to actual measurements of AFP.

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In order to accurately determine major elements (Cu, Al, Fe, Ni and Mn) in milligram amounts of aluminum bronze reference samples, an application of ICP-AES using scandium as an internal-standard element was investigated. The correlation coefficient of the emission intensities of each major element to scandium was above 0.95, and the repeatable precision in measuring the emission intensity ratio of each major element to scandium was 0.11∼0.43% (RSD, %, n=25), which corresponded to 1/2∼1/6 times that obtained without an internal standard. In an analysis with a 10 mg or a 5 mg amount of the sample, the relative variances for 5 major elements {Relative variance (%)=[(M_found)-(M_cert)/M_cert]×100, where M_found and M_cert are the found and certified values, respectively}. were -3.1∼+4.4%, except for Mn, whose content in the sample was under 1%. Based on these results, the proposed method will offer an advantage of improving the precision and accuracy in the analysis of milligram amounts of aluminum bronze samples.

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A simple method for the spectrophotometric determination of trace surfactants based on a preconcentration technique involving collection on a cellulose powder was developed. A cationic surfactant (CS⁺), such as quaternary ammonium salts containing a long-chain alkyl group, was collected on a cellulose powder as a 1 : 1 ion associate with a monovalent Bromochlorophenol Blue anion (HBCPB^-). For the anionic surfactant (AS^-), CS⁺ was added to AS^- and similarly the ion associate of excess CS⁺ with HBCPB^- was collected on cellulose powder. After filtration, the cellulose powder with an ion associate, CS⁺ · HBCPB^-, was stirred with a small volume of an alkaline solution. The absorbance of divalent BCPB^2- in the solution after centrifuging was measured at 590 nm. The absorbance at 590 nm increased and decreased with increasing the amount of CS⁺ and AS^-, respectively. A calibration graph based on this principle shows linearity up to 5×10^-7 M of CS⁺ and AS^-. The proposed method is simple and rapid, and there is no use of toxic organic solvents.

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It is well known that Ir is a chemically stable element that is difficult to dissolve even in a strong acid. Furthermore, when transition metals are added to it, Ir becomes more difficult to dissolve in acid. To solve this problem, we tried to dissolve Ir alloys including several transition metals using a fusion method at 800°C in sodium peroxide. We found that, when the powder size of a sample was sufficiently small, under 75 μm, Ir alloys could be dissolved. We also showed that it is possible to analyze the composition of Ir alloys using the solution with ICP-AES.

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Before the determination of bisphenol A (BPA) by GC/MS, it is preferable to convert it to a less polar compound to eliminate the adsorption of a polar analyte on the wall of the instrument and to obtain a sharp peak in the chromatogram and a high sensitivity. Although it seems that in situ acetylation producing the acetyl derivative of BPA (BPADA) is simple and rapid, for solid-phase extraction (SPE) an undesirably low recovery may result from a possible strong interaction between BPADA and the solid-phase. Thus, the octadecyl-bonded phase (C₁₈ phase) and the cyanopropyl-bonded phase (CN phase) were compared for the SPE of BPADA at the 0.1 μg ml^-1 level. The former is an apolar phase and the latter has intermediate polarity. The results showed that the CN phase gave more satisfactory results than the C₁₈ phase for recovery and precision. Furthermore, for trace determination with SPE/GC/MS after in situ acetylation, it was found that the cyanopropyl phase gave a lower blank and a lower detection limit compared with the C₁₈ phase. Using the cyanopropyl phase and a 500 ml of sample solution, the detection limit was 0.09 ng and the recoveries of 5.0 and 10.0 ng of BPA were 107±6 and 99.6±2.8% (mean±standard deviation) for four repeated runs, respectively. The present method was applied to the study of a degradation of BPA due to chlorine in tap water.

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The frequency of an electrode-separated piezoelectric quartz crystal shifted in a solution of sodium oleate surfactant, which is the main component of solid soap. All solutions of 10 marketed solid soaps marketing also gave frequency shifts. A quartz plate coated with collagen, which is very much like human skin, showed the same behavior in frequency as a quartz plate without collagen, except for an increasing frequency. The soap components adsorbed were not desorbed in deionized water. These results indicate that soap components remain on glasses, dishes and human skin after simple rinsing with water.

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Studies on capillary electrophoresis (CE) were attempted in order to develop novel and simple migration systems to control the electroosmotic and electrophoretic mobility and to improve the resolution. First, a zwitterionic surfactant (Zwittergent-3-14) was very useful to suppress the adsorption of proteins to the capillary wall and to control the electrophoretic mobility of inorganic anions by modifying the electroosmotic flow. This system was successfully applied to the determination of ionic components in real samples as follows (1) a vitamin (biotin) in a tablet, (2) NO₂^-, NO₃^-, and SCN^- in human saliva samples, and (3) Br^- in seawater. Second, some charged cyclic compounds were examined as CE additives for the separation of structural and positional isomers. Negatively charged cyclodextrin (sulfonated-β-cyclodextrin) was effective in the separation of several alkylphenols and bisphenols. Under the optimized CE condition, the structural isomers of nonylphenol could be successfully distinguished by more 20 individual peaks. Cationic diazacrown ethers having quaternary ammonium ions were useful as CE additives to improve the resolution among the positional isomers of divalent aromatic anions. The ion association constants between the cationic diazacrown and analyte anions were evaluated and the separation mechanism was considared. These studies using several novel additives provided an improvement in the peak efficiency, the peak resolution and the peak reproducibility in CE separation.

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Electrochemical detection offers advantages of simple instrumentation, inherent sensitivity and extreme selectivity for use in HPLC. However, most amino acids cannot be detected by constant-potential amperometry at conventional carbon electrodes. Therefore, to detect amino acids and related compounds electrochemically, novel direct and indirect detection systems have been developed. First, a Ni-Ti alloy was characterized and used as a detector for the analysis of amino acids. As a result, the Ni-Ti alloy electrode exhibited a high degree of reproducibility as an electrode material due to the stability of the oxide film. Secondly, an indirect electrochemical detection method has been developed based on the use of a carbon film ring-disk electrode. This method exhibited the lower limit of detection for amino acids with large aliphatic side chains, which were very poor in sensitivity at metal electrodes. Thirdly, from the viewpoint of providing a screening method for forensic and emergency toxicology, integrated pulsed amperometry was applied to detect phosphorus-containing amino acid-type herbicides (glufosinate, bialaphos and glyphosate). Finally, the ability of pencil leads has been exploited for the electrochemical detection of phenol and chlorophenols. These varied approaches provide numerous advantages, such as simplicity, high sensitivity and reproducibility, for detecting amino acids and related compounds without prior derivatization.

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