Flame retardants (FRs) are useful because they can prevent combustion and delay the spread of fire after the ignition on commercial products containing plastics. However, such commercial products could be a primary source of environmental contamination with FRs. Plastic disks containing FRs were prepared to elucidate changes in the concentrations of the FRs after weathering tests. Acrylonitrile-butadiene-styrene (ABS) and polycarbonate (PC) resin were separately kneaded with a combination of three organic FRs [Dechlorane plus (DP), tetrabromobisphenol A (TBBPA), and triphenyl phosphate (TPhP)] and one inorganic FR [antimony trioxide (SbO)]. The concentrations of TBBPA/TPhP and DP/SbO in the final preparations were respectively 1000 and 500 mg/kg in compliance with the RoHS directive on organobromine FR. The concentrations of elements in the final preparations were 300 mg/kg for chlorine, 600 mg/kg for bromine, 100 mg/kg for phosphorus, and 400 mg/kg for antimony, respectively. The analytical concentrations (three FRs and four elements) were consistent with the expected concentrations (maximum difference -9.5% in the PC disks). The FRs and elements in the disks were sufficiently homogenous (maximum inhomogeneity 4.3% in the PC disks). The prepared disks were subjected to weathering tests; the concentrations of TBBPA in the disks decreased significantly (30 to 40%) whereas the concentrations of the elements did not change under the condition of this study. On the other hand, there were no drastic differences on relationships of FRs and elements such as DP/chlorine and TPhP/phosphorus.
The Kamioka mine, located in Gifu Prefecture in Japan, is famous for the large water Cherenkov detector system, the Super-Kamiokande. The Kamioka skarn-type Pb–Zn deposits are formed in crystalline limestone and are replaced by skarn minerals within the Hida metamorphic rocks. The Kamioka deposits mainly consist of the Tochibora, Maruyama, and Mozumi deposits. The present study focuses on the ore-forming hydrothermal fluid activity in the Kamioka deposits and the peripheral exploration area based on the carbon and oxygen isotope ratios of calcite and rare earth element (REE) analyses. The carbon and oxygen isotope ratios of crystalline limestone (as the host rock) are not homogeneous, and depending on the degree of hydrothermal activity, they decreased to various degrees because of the reaction with the ore fluids. Thus, the carbon and oxygen isotope ratios of crystalline limestone can be used as an indicator of the influence of the hydrothermal fluids for the ore mineralization. The REE contents in the ores of igneous origin are one order of magnitude higher than the limestone origin. Further, depending on the formation temperatures, calcites precipitated during ore mineralization have a stable carbon isotope ratio and a widely varying oxygen isotope ratios. The Kamioka district fracture system is likely a major control factor on ore mineralization from hydrothermal activity. In addition, the skarnization-related ore-forming fluids are mostly meteoric in origin, confirming the conclusions from previous studies.
The determination of chlorine (Cl) in plastic using isotope dilution inductively coupled plasma mass spectrometry (ID-ICPMS) combined with different sample pretreatment procedures was examined in the present study.
The analytical method for ultra-trace metal impurities at μg kg -1 level in high-purity Cd was examined by inductively coupled plasma mass spectrometry (ICP-MS) combined with matrix separation by Bio-Rad AG MP-1M anion exchange resin. After the separation of Cd, the metal impurities such as Li, In, Cr, Mn, Fe, Co, Ni, Cu, Ga, Sr, Ba and Pb were measured by an ICP-quadrupole mass spectrometer (ICP-QMS) and ICP-sector field mass spectrometer (ICP-SFMS). From the comparison of measured results, it was evaluated that the analytical sensitivity by ICP-SFMS was 10 times higher than ICP-QMS. In addition, ICP-SFMS could obtain determined values of Li and Fe that could not be determined by ICP-QMS. These results suggest the ICP-SFMS combined with matrix separation by anion exchange resin could be utilized for the determination of ultra-trace metal impurities in high-purity materials for the assessment of the purity of the materials.
Gravimetric analysis was used to determine the purity of high-purity La2O3 by stepwise conversions of the weighing forms. In this study, lanthanum in the sample was converted to La oxalate, La2O3, and La2(SO4)3 to evaluate the stoichiometry of the weighing forms for accurate gravimetric determination. The losses of La in the filtrate, the washing solution of the precipitate, and the mechanical loss of La during filtration were measured using inductively coupled plasma optical emission spectrometry. The weighing forms were evaluated by comparing the observed mass ratio with the theoretical value at each conversion step. The final converted La2(SO4)3 was consistent with the theoretical composition based on the observed mass ratio of La2(SO4)3/La2O3. Additionally, impurities in the high-purity La2O3 were determined by inductively coupled plasma tandem mass spectrometry. The purity of the original La2O3 sample was precisely determined to be 99.977 % ± 0.057% (mass fraction as La2O3; the value following “±” indicates the expanded uncertainty with a coverage factor k = 2.18) by a combination of the gravimetric analysis using the precipitation from the homogeneous solution method and verification of the weighing forms for La compound.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.