Hideyoshi Morita

Rare earth elements (REEs) in naturally grown plants in relation to their variation in soils

The concentrations of rare earth elements (REEs) in plant leaves, soils in which they grow, and mother rocks were determined using Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). Concentration levels of REEs in most plants were low. However, one of the herb species, pokeweed (Phytolacca americana) and two species of ferns (Dicranopteris dichotoma and Athyrium yokoscence) revealed relatively high concentrations of REEs. In the case of pokeweed, the REE distribution pattern reflected well that of its soils. On the whole, high concentrations of REEs in plants were related to REE concentrations in the soils in which they grow. These observations are promising to evaluate the possible contamination of environment by REEs resulting from their increased usage in modern industry.

Atomic fluorescence spectrometry of mercury: principles and developments

Abstract Atomic fluorescence spectrometry (AFS) of mercury is very sensitive and the AFS system is an excellent detector for mercury analysis. The first part of this review covers the principles of determination of mercury by AFS. The second part delineates the loss and increase of mercury through its transfer between the gas and solution phases. The third part addresses some possible interferences in the determination of mercury by AFS. The fourth part describes preconcentration techniques for mercury species. In the fifth part, methods for total and selective determination of mercury are described. In the sixth part, various types of automated and semi-automated procedures for the determination of mercury are summarized. Finally, representative biological and environmental certified reference materials (CRMs) for mercury analysis are presented and the availability of CRMs in checking the accuracy and precision of the methodologies is briefly described.

Analysis of serum elements and the contaminations from devices used for serum preparation by inductively coupled plasma mass spectrometry

Two different samples of serum were prepared from a blood specimen by using two types of serum-separation tubes. Each serum sample was diluted by 100 times with deionized and sub-boiling distilled water. Thirty-six elements in the serum and exudate, from devices used for the serum preparation, were determined by inductively coupled plasma mass spectrometry (ICP-MS). From the comparison of elemental concentrations in two groups of 11 serum samples, it was found that the exudate from serum-separation tubes, as well as from disposable stainless steel needles, had serious effects on the elemental concentrations in the serum. Means for the concentrations of Li, Co, Ga, Cd, Sn, Sb, Ba, La, and Ce in the two serum groups were statistically different from each other. The concentrations of Cr, Mn, Fe, and Mo in both groups were apparently higher than those reported in the literature, suggesting contamination from the disposable stainless steel needle and spectral interferences due to molecular species produced in the argon plasma.

Absorption of mercury by solutions containing oxidants

Abstract The transfer of mercury vapor into solutions containing mercury(II) ions and/or oxidants (dichromate, permanganate, cerium(IV) sulfate, silver nitrate) is investigated. The rate of absorption increases with increasing Hg 2+ concentration and with increasing oxidation potential of dichromate solutions in sulfuric acid. A mechanism is proposed for the transfer.

Flow Injection Analysis of Mercury/Cold Vapor Atomic Fluorescence Spectrophotometry

Abstract A new flow injection system for the determination of mercury by the cold vapor atomic fluorescence method is described. A sample solution (64 μ1) is injected into a stream of 0.1 M hydrochloric acid, which is mixed with a stream of 3% tin (II) chloride solution in a mixing joint. The combined stream is carried through a reaction coil for reduction of Hg (II) to Hg (0) and subsequently introduced into a specially designed gas-liquid separation vessel. Then the vaporized mercury is swept into a flow type fluorescence cell with a continuous flow of argon after removal of water in the gas phase through a condenser. Mercury is excited with an electrodeless discharge lamp as a source and the mercury fluorescence at both 184.9 and 253.7 nm is measured with a solar-blind photomultiplier. This method allows about 35 determinations of mercury in aqueous samples per hour. The calibration curve is linear over the 0–20 ppb range of mercury. The limit of detection (S/N = 3) is 0.008 ng (0.12 ppb × 64 μ1) and t...

Interrelationships between the concentration of magnesium, calcium, and strontium in the hair of Japanese school children

Inductively coupled atomic emission spectrometry was used for the determination of magnesium, calcium and strontium in the hair of Japanese school children (7-15 years of age, 158 males and 184 females). Sex-related differences in the levels of the three alkaline earth metals were observed (T-test, p less than 0.001). Geometric means (SD) of the concentrations of magnesium, calcium and strontium were 30.40 (1.42), 326.3 (1.62) and 0.509 (2.04) micrograms g-1 for males and 61.21 (1.73), 643.4 (1.57) and 2.749 (2.14) micrograms g-1 for females. For both sexes, significant positive correlations were observed between all concentration pairs of the three elements. The concentration ratios between any two of the three elements were also determined. The geometric mean of the concentration ratio of calcium to magnesium for males [10.73 (1.54)] is not significantly different from that for females [10.51 (1.40)] (T-test, p greater than 0.05). On the other hand, concentration ratios of magnesium to strontium [59.71 (1.99)] and calcium to strontium [640.9 (1.74)] for males are significantly higher (T-test, p less than 0.01) than those for females [22.27 (1.60) and 235.9 (1.65)]. The logarithmic-transformed ratio of magnesium to strontium has a strong positive correlation with the transformed ratio of calcium to strontium [r = 0.9529 (p less than 0.001) for males and r = 0.7284 (p less than 0.001) for females].

Determination of germanium and some other elements in hair, nail, and toenail from persons exposed and unexposed to germanium

Inductively coupled atomic emission spectrometry was used for the determination of germanium in hair, nail, and toenail. The levels of germanium in three individuals administered a high concentration of a germanium preparation daily for about 12-16 months were very high: 56.4-173.7; 5.4-35.0; and 14.0-15.8 micrograms g-1 in hair, nail, and toenail, respectively. The levels for normal or unexposed persons are very low and were not detected by the method.

Determination of germanium by atomic absorption spectrometry after solvent extraction—enhancement of sensitivity by a nebulizer effect

Abstract Germanium can be determined by atomic absorption spectrometry after extraction into n-butyl ether. Germanium is first extracted with n-butyl ether from 8 M hydrochloric acid, and the extract is shaken again with 12 M hydrochloric acid. A ca. 5-fold enhancement of sensitivity is obtained compared with an earlier procedure based on methyl isobutyl ketone. This enhancement is ascribed to a “nebulizer effect”, and is probably due to the different chemical forms of germanium produced when germanium is extracted from various concentrations of hydrochloric acid.

Behavior of Mercury Vapor Upon Irradiation by a Mercury Lamp in an Inert Gas

Abstract The behavior of mercury vapor during irradiation by a mercury lamp is investigated. Using the flameless atomic absorption technique for mercury determination, it was found that when mercury vapor in an inert gas is irradiated by a mercury lamp, the atomic absorption signal of mercury is decreased rapidly and the signal may be restored by heating to 70°C. These phenomena indicate that the irradiation products of mercury vapor in the quartz tube are deposited on the tube, and are dissociated into the mono-atomic state of mercury upon heating.

Vaporization Phenomena of Monoatomic State of Mercury Through Acidic Solution

Abstract The vaporization process of the monoatomic state of mercury [mercury (0)] in acidic solution is investigated. The determination of vaporized mercury (0) is performed by a flameless atomic absorption method. It was found from the experiments that the vaporization of mercury (0) is based on the oxidation reaction of mercury to mercury (I) by oxidizing agents such as ferric and silver ions, and the disproportionation reaction of mercury (I) in acidic solution; The complex-forming anions such as halides, cyanide and sulfide markedly suppressed the vaporization of mercury (0) and the order of the suppression effect with halides is; I− > Br− > Cl− > F−.