Merging Pd0 /PdII Redox and PdII /PdII Non-redox Catalytic Cycles for the Allylarylation of Electron-Deficient Alkenes.

An allylarylation of electron-deficient alkenes with aryl boronates and allylic carbonates has been developed. This method allows access to a wide variety of carbon skeletons from readily available starting materials. Mechanistic studies indicate that this reaction is enabled by a cooperative catalysis based on merging Pd0 /PdII redox and PdII /PdII non-redox catalytic cycles.

Evaluation of flame retardancy and flexural property on prepared plastic disks containing known concentrations of flame retardants through simulated weathering tests.

The standardized acrylonitrile-butadiene-styrene (ABS) or polycarbonate (PC) resin disk with added flame retardants (FRs) has a potential to be a suitable tool for predictions of both aging of the plastic materials and release rate of a flame retardants exposed under different outdoor and indoor conditions. The experiments examined the dynamics and kinetics of the release of dechlorane plus, tetrabromobisphenol A, triphenyl phosphate and antimony trioxide as FRs from a standardized plastic disk before and after exposure to artificial sunlight. Assessments were carried out independently to measure changes in the content of flame retardants and monitor the flame retardancy and flexural properties after exposure (60 W/m2) over a period of 200 h and 500 h, which are reasonable to predict a short-time tendency and to receive any advice for a safe re-use. The releases of three organic flame retardants and four elements (Cl, Br, P and Sb) from weathered ABS and PC disks were very limited, except for surface delamination and resin microparticles. Triphenyl phosphate was stable without hydrolysis, while the degradation of tetrabromobisphenol A was observed (approximately 20% decrease for ABS disk and approximately 50% decrease for PC disk). During the study, no significant differences in the flame retardancy and flexural properties of the disks could be detected. In practice, the results obtained from disks of acrylonitrile-butadiene-styrene or polycarbonate resin with selected flame retardants used in specific conditions may provide technical expertise regarding weathering processes.

Direct Quantitation of 135Cs in Spent Cs Adsorbent Used for the Decontamination of Radiocesium-Containing Water by Laser Ablation Inductively Coupled Plasma Mass Spectrometry.

The long-term safety assessment of spent Cs adsorbents produced during the decontamination of radiocesium-containing water at the Fukushima Daiichi nuclear power plant requires one to estimate their 135Cs content prior to final disposal. 135Cs is usually quantified by inductively coupled plasma mass spectrometry (ICP-MS), which necessitates the elution of Cs from Cs adsorbents. However, this approach suffers from the high radiation dose from 137Cs that is present in the contaminated water and Cs adsorption irreversibility. To address these challenges, we herein employed laser ablation ICP-MS for direct quantitation of 135Cs in Cs adsorbents and used a model Cs adsorbent prepared by immersion of a commercially available Cs adsorbent into radiocesium-containing liquid waste to verify the developed technique. Crushing and subsequent coating with a nitrocellulose-based curing agent provided a thin flat surface and thus allowed for stable solid sampling during laser ablation. The use of the 135Cs/137Cs ratio and 137Cs radioactivity obtained by gamma spectrometry achieved simple and precise quantitation of 135Cs. The obtained 135Cs/137Cs ratio of 0.41 ± 0.02 well agreed with that obtained for the original liquid waste sample by solution nebulization measurements, and the proposed method was concluded to be suitable for large-scale 135Cs quantitation, requiring only very small (<10 mg) samples with total 137Cs radioactivity.

Peg1/Mest, an imprinted gene, is involved in mammary gland maturation.

Imprinted genes, which are specific to mammals, play important roles in cell proliferation, differentiation, ontogeny, and other phenomena. Moreover, these genes are considered crucial in the research of mammalian evolution. In the current study, we investigated the association between the expression of paternally imprinted gene paternally expressed 1/mesoderm-specific transcript (Peg1/Mest) and the maturation of the mammary gland. Quantitative real-time polymerase chain reaction analysis of Peg1/Mest gene expression at different stages of mouse mammary gland maturation revealed that its expression increased during gestation but decreased during lactation. Immunohistochemical staining demonstrated that Peg1/Mest was expressed in mammary epithelial cells. We measured expression levels of Peg1/Mest and E-cadherin during mammary alveoli formation using immunofluorescence staining a cell model for mammary alveoli formation in a 3D culture system. We found that the onset of E-cadherin expression roughly coincided with the peak of Peg1/Mest expression. Moreover, we discovered that the formation and proliferation of alveoli were suppressed in Peg1/Mest knockdown mammary epithelial cells. These results suggest that Peg1/Mest plays a certain role in mammary alveoli formation. To clarify the role of Peg1/Mest in the lactogenic differentiation of mammary epithelial cells, we examined the lactogenic differentiation capability of Peg1/Mest-overexpressing HC11 cells. Application of a differentiation-inducing stimulus did not increase ß-casein expression in Peg1/Mest-overexpressing HC11 cells. The current study for the first time reports the involvement of an imprinted gene in mammary gland maturation.

Determination of 107Pd in Pd purified by selective precipitation from spent nuclear fuel by laser ablation ICP-MS.

Determination of radiopalladium 107Pd is required to ensure radiation safety of the Pd extracted from spent nuclear fuel for recycling or disposal. We employed nanosecond laser ablation inductively coupled plasma quadrupole mass spectrometry (ns-LA-ICP-QMS) to simplify the analytical procedure of 107Pd. Pd was separated through a selective Pd precipitation reaction induced by pulsed laser irradiation that reduces Pd(II) ions to metal Pd(0). Laser ablation facilitates direct measurement of the Pd precipitates, skipping the dissolution and dilution procedure with aqua regia and HCl, which causes serious corrosion damage to the introduction system of the ICP. In the present study, 102Pd in natural Pd standard solution was used as an internal standard owing to its absence in spent nuclear fuel. Pd precipitates with diameters ranging from 0.2 to 0.5 µm, obtained by pulsed laser irradiation, were embedded uniformly on the surface of the centrifugal filter to form a microscopically thin and flat Pd surface. The resulting homogeneous Pd layer is suitable for obtaining a stable signal ratio of 107Pd/102Pd (< 4%, 2RSD). The mass bias-corrected ratio of 107Pd/102Pd and the amount of 107Pd were 0.163 ± 0.004 and 17.8 ± 0.6 ng, respectively, which correspond to the values obtained by solution nebulization measurement after the dissolution of identical Pd precipitates. Graphical abstract ᅟ.

Development of plastic disks containing flame retardants for elucidating changes in their concentrations due to simulated weathering and the application of these disks to weathering tests.

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 (Sb2O3)]. The concentrations of TBBPA/TPhP and DP/Sb2O3 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.

ALS-Linked P56S-VAPB Mutation Impairs the Formation of Multinuclear Myotube in C2C12 Cells.

Amyotrophic lateral sclerosis (ALS) is a rapidly progressive neurodegenerative disorder that affects upper and lower motor neurons. Since motor neurons target skeletal muscles, the maintenance system of muscles is disturbed in ALS; however, the mechanism by which this occurs is unknown. In the present study, we investigated the effects of ALS-associated P56S-vesicle-associated membrane protein-associated protein B (VAPB) (P56S-VAPB) on the IRE1-XBP1 pathway, which is involved in the unfolded protein response (UPR) of the mouse myoblast cell line (C2C12 cells). Experiments with C2C12 cells transfected with wild-type wt-VAPB and P56S-VAPB expression vectors showed reduced myotube formation and aberrant myonuclear position in cells expressing P56S-VAPB. Activity of the IRE1-XBP1 pathway in the cells visualized with the ERAI system revealed that the pathway was disrupted in cells expressing P56S-VAPB, whereas the IRE1-XBP1 pathway activity was enhanced in the differentiation process of normal C2C12 cells. These results suggest that disruption of the IRE1-XBP1 pathway is a cause for the reduced myotube formation in P56S-VAPB-expressing cells. The expression level of the VAPB protein has been reported to be reduced in the neurons of patients with ALS. Therefore, it is expected that the IRE1-XBP1 pathway is also impaired in muscle tissues of patients with ALS, which causes a disturbance in the muscle maintenance system.

Gas to particle conversion-gas exchange technique for direct analysis of metal carbonyl gas by inductively coupled plasma mass spectrometry.

A novel gas to particle conversion-gas exchange technique for the direct analysis of metal carbonyl gas by inductively coupled plasma mass spectrometry (ICPMS) was proposed and demonstrated in the present study. The technique is based on a transfer of gas into particle, which can be directly analyzed by ICPMS. Particles from metal carbonyl gases such as Cr(CO)6, Mo(CO)6, and W(CO)6 are formed by reaction with ozone (O3) and ammonium (NH3) gases within a newly developed gas to particle conversion device (GPD). The reaction mechanism of the gas to particle conversion is based on either oxidation of metal carbonyl gas by O3 or agglomeration of metal oxide with ammonium nitrate (NH4NO3) which is generated by the reaction of O3 and NH3. To separate the reaction gases (remaining O3 and NH3) from the formed particles, a previously reported gas exchange device (GED) was used and the in argon stabilized analyte particles were directly introduced and measured by ICPMS. This new technique provided limits of detection (LOD) of 0.15 pL L(-1) (0.32 ng m(-3)), 0.02 pL L(-1) (0.07 ng m(-3)), and 0.01 pL L(-1) (0.07 ng m(-3)) for Cr(CO)6, Mo(CO)6, and W(CO)6, respectively, which were 4-5 orders of magnitude lower than those conventional applied for detecting these gases, e.g., gas chromatography with electron captured detector (GC-ECD) as well as Fourier transform-infrared spectroscopy (FT-IR). The achieved LODs were also similar or slightly better than those for ICPMS coupled to GC. Since the gas to particle conversion technique can achieve the direct measurement of metal carbonyl gases as well as the removal of reaction and ambient gases from metal carbonyl gases, the technique is considered to be well suited to monitor gas quality in semiconductor industry, engine exhaust gases, and or waste incineration products.

Video stimuli suitable for stress estimation based on biosignals.

Stress can cause mental disorders such as depression and anxiety disorders. To detect such mental disorders at an early stage, it is necessary to detect stress accurately. One of the effective methods for this purpose is observing changes in biological signals caused by sensory stimuli such as video presentation. This study aims to identify effective video stimuli for stress estimation. We hypothesize that the emotional state evoked by the video stimuli influences the accuracy of stress estimation. To test this hypothesis, we utilized an open video dataset consisting of 444 responses on an emotion scale (valence and arousal) as emotional stimuli. Ninety videos were divided into emotion subsets based on the emotion scale for each video, and biological signals were measured when each video was presented to the subjects. Machine learning models were constructed for each subset, and the prediction errors were compared. The results showed that the prediction error was lower for the high valence and high arousal subsets than for the others. These results suggest that high-valence or high-arousal videos effectively estimate stress.

Analytical Efficacy of a Gas Mixer and Stabilizer for Laser Ablation ICP Mass Spectrometry.

The analytical efficacy of five gas mixers and five stabilizers on signal stabilization and washout time obtained for laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) was evaluated in the present study. In the case of gas mixers examined, a total of 95 patterns of their attitudes as well as different directions of the gas flows were examined, and it was found that the signal variation and the washout time were strongly dependent on these factors. Even in a simple Y-shaped fitting (Y-mixer), signal stability and washout time had large variations with respect to its different attitudes as well as gas flow directions. The shortest washout time for each gas mixer was almost the same ranging from 1.0 to 1.2 s. The signal variations observed were 11-15% of relative standard deviation (RSD) under optimum conditions for each gas mixer. The optimum condition of a Y-mixer for LA-ICPMS represented 11% RSD and 1.0 s for signal variation and washout time, respectively. In the case of stabilizers examined, almost all stabilizers improved signal variations from 11 to 3.0-9.3%, but washout times became longer than those of the only Y-mixer from 1.0 to 1.2-8.9 s. The important thing is that the signal stability and the washout time are trade-off correlations for gas mixers and stabilizers. A suitable gas mixer or a stabilizer on the trade-off line can be selected with respect to different applications. It was also observed that variations of both signal stability and washout time correlated with the volume of stabilizers despite their different inner structures; that is, a stable signal and longer washout time seemed to be observed when the volume of the chamber became larger. This suggested that the signal stabilization obtained by stabilizers was ascribable to not only elimination of larger particles from laser ablation but also particle mixing effect, which compensated signal variation.

Evaluation of the Calibration Method for Accurate Analysis of Dissolved Silica by Continuous Flow Analysis.

For accurately determining nutrients in seawater by continuous flow analysis (CFA), the characteristic of the calibration curve was examined in detail. Under absorbance below 0.8, the calibration curve and the bracketing methods showed more accurate results that the bias fell below 0.5%. The analytical results of dissolved silica in seawater from the nutrient maximum layer of the Pacific Ocean obtained by the proposed methods showed good agreement with those obtained by an ion exclusion chromatography postcolumn absorption spectrophotometry (IEC-postcolumn) and an ion exclusion chromatography isotope dilution ICP mass spectrometry (IEC-ID-ICP-MS). From the results, the analysis of nutrients in seawater could be accurately carried out by CFA with an expanded uncertainty of below 1% using both the calibration curve and the bracketing methods with an appropriate absorbance range.

Research Progress on Gas to Particle Conversion-Gas Exchange ICP-MS for Direct Analysis of Ultra-trace Metallic Compound Gas.

A novel gas to particle conversion-gas exchange technique coupled with inductively coupled plasma mass spectrometry (GPD-GED-ICP-MS) was recently proposed for the direct analysis of ultra-trace levels of metallic compound gases such as metal carbonyl and semiconductor gases as well as gaseous mercury (Hg) in ambient air. These metallic compound gases should reveal reactivity with respect to ozone and gas to particle conversion could be obtained in a gas to particle conversion device (GPD) through metal oxides by oxidation. The particles converted were separated from non-reactive gases such as nitrogen, oxygen, carbon dioxide in ambient air by a gas exchange device (GED) and the particles in argon, otherwise ICP cannot be maintained, were directly introduced and measured by ICP-MS. Since the technique detects the metallic compound gas directly without any sampling methods, it is expected to be applied to real-time monitoring. This article highlights the research progress and novelty on GPD-GED-ICP-MS for the direct analysis of ultra-trace metallic compound gas. It was also noted that the direct analysis of gaseous Hg at the concentration level of a few ng m-3 in ambient air mentioned in this article was world-first achieved by GPD-GED-ICP-MS. The research progress for multi-element analysis in suspended particulate matter by GED-ICP-MS was also mentioned since the GED was always used for GPD-GED-ICP-MS.

Determination of ultra-trace sulfur in high-purity metals by isotope dilution inductively coupled plasma sector field mass spectrometry combined with chemical separation procedure.

The analytical method of ultra-trace sulfur (S) in high-purity metal by isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS) combined with chemical separation procedure was developed in the present study. In order to determine the ultra-trace S in high-purity metal, a chemical separation with alumina column was carried out before ICP-MS measurement. This method enabled to prevent the polyatomic ion interference arising from the metal matrix and the signal suppression derived from the space charge effect in ICP-MS. In order to achieve high sensitive analysis, an ICP-sector field mass spectrometer (ICP-SFMS) was used. The isolation of polyatomic ion interference with respect to S was also carried out in medium-resolution mode. In addition, measurement conditions including detector dead time, which affects the precision and accuracy of the isotope dilution method, and washout conditions that were employed to reduce memory effects were optimized. The developed method was validated by the determination of S in a high-purity iron reference material (JSS-001-4). The analytical result obtained by the developed method (1.86 mg kg-1 ±â€¯0.12 mg kg-1 (k = 2)) was in good agreement with the certified value (1.90 mg kg-1 ±â€¯0.42 mg kg-1). The method was also applied to the determination of S in high-purity zinc, revealing a content of 0.08 mg kg-1 ±â€¯0.08 mg kg-1 (k = 2). Since the developed method enabled the determination of ultra-trace S at µg kg-1 level in the high-purity zinc, it is expected to be useful for high sensitive and accurate determination of ultra-trace S in high-purity metals.

Determination of Fluorine Chemical Structure in Slag by Thermal Hydrolysis He-MIP-OES.

A novel microwave-induced helium plasma optical emission spectrometry (He-MIP-OES) combined with a thermal hydrolysis sample introduction system was newly established for the determination of fluorine (F) compounds in slags. The MIP maintained through an Okamoto cavity was adopted, which was quite stable and provided a higher detection capability of F by helium plasma. The basic analytical performance of He-MIP-OES combined with an ultrasonic nebulizer for F analysis was also examined, and expected results could be obtained. The thermal hydrolysis behavior of CaF2, Ca4(Si2O7)(F,OH)2 and Ca5(PO4)3F, as known F chemical structures in slag, was also examined by thermal hydrolysis He-MIP-OES; F compounds in actual slag could be successfully identified and determined by this developed system.

Examination of the Mass Transfer of Additive Elements in Barium Titanate Ceramics during Sintering Process by Laser Ablation ICP-MS.

The mass transfer of additive elements during the sintering of barium titanate (BaTiO3) ceramic was examined by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) in the present study. An analytical sample consisting of two pellets of BaTiO3 with different concentrations of additive elements of manganese (Mn) and holmium (Ho) as well as silicon (Si) as a sintering reagent was prepared and measured by LA-ICP-MS with small laser irradiated diameter of 10 µm to evaluate the distributions and concentrations of additive elements in order to examine their mass transfers. As results, enrichments of Mn and Si as an additive element and a sintering reagent, respectively, were observed on the adhesive surface between two BaTiO3 pellets, even though Ho did not show a similar phenomenon. The mass transfers of additive elements of Mn and Ho were also examined, and Mn seemed to show a larger mass transfer than that of Ho during the sintering process for BaTiO3 ceramics. The results obtained in this study shows the effectives of LA-ICP-MS for the future improvement of MLCCs.

Effect of Long-time Heating for Elements from Flame Retardants in Acrylonitrile Butadiene Styrene and Polycarbonate Resin Disks.

The effect of long-time heating for elements from flame retardants (FRs) such as dechlorane plus (DP), tetrabromobisphenol A (TBBPA), triphenyl phosphate (TPhP) and antimony trioxide (Sb2O3) in both acrylonitrile-butadiene-styrene (ABS) and polycarbonate (PC) resin disks was examined in the present study. The heating temperature by a drying oven was 80°C, which was expected to be a harder environment than that of usual dump site to discard electric and electronic equipment, and the long-time heating was carried out for up to 722 days. As a result, the increases for both ether (C-O-C) and ketone (C=O) groups and the decrease of C=C double bond as well as methylene group (=CH2) were found for an ABS resin disk by fourier transform infrared (FTIR) spectrometry, which was expected to result in an increase of mass of the disk up to ca. 4% due to oxidation during the long-time heating. The changes in concentrations for bromine (Br), chlorine (Cl), phosphorous (P) and Sb, which were originated elements from FRs contained, were also evaluated by energy dispersive X-ray fluorescence (ED-XRF) spectrometry and the decreases in concentrations of ca. 5% in ABS resin disk were observed which could be almost explained by increasing ca. 4% mass of the disk. On the contrary, the mass and chemical form of a PC resin disk as well as the concentrations of elements contained did not change during the long-time heating. From these results, it could be considered that most of the elements from DP, TBBPA, TPhP and Sb2O3 contained as FRs in the ABS and PC resin disks examined in the present study were not lost during the long-time heating, even though the color, shape, mass and chemical form of ABS resin disk were changed.

Studies on Isotope Ratio Measurement of Cl by Inductively Coupled Plasma Triple-quad Mass Spectrometry.

Fundamental studies on isotope ratio measurement of Cl were carried out using inductively coupled plasma triple-quad mass spectrometry (ICP-MS/MS) and the analytical performance obtained was compared to that obtained by ICP sector field mass spectrometer (ICP-SFMS). Though the polyatomic ion interferences of 16O18O1H and 36Ar1H with respect to 35Cl and 37Cl, respectively, made a negative effect on the accuracy and the precision for isotope ratio measurements of Cl, the ICP-SFMS could eliminate these interferences by medium mass resolution mode (m/Δm = 4000) and achieved the isotope ratio measurements with 0.2 - 0.5% of relative standard deviation (RSD) at the concentrations of Cl from 1 to 10 mg kg-1. In the case of ICP-MS/MS, both the single-MS mode without collision reaction gas and the MS/MS mode with collision reaction gases such as oxygen (O2) and hydrogen (H2) were examined and compared their analytical sensitivities as well as the precisions of isotope ratio measurement of Cl. The precisions of Cl isotope ratio measurements were 3 - 14% of RSD at the concentrations of Cl from 5 to 100 mg kg-1, when single-MS mode was carried out, even though the similar isotope ratios of 35Cl/37Cl could be obtained. In the case of O2 gas for MS/MS mode with mass-shift method, precisions of 0.3 - 2% of RSD were obtained at the concentration range of 1 - 100 mg kg-1. In the case of H2 gas, similar sensitivities as those obtained by ICP-SFMS and the precisions of 0.2 - 0.5% of RSD at the concentration range of 1 - 10 mg kg-1 were obtained. From these results, it was evaluated that the ICP-MS/MS in MS/MS mode with collision reaction gas could be used for Cl isotope ratio measurements for such studies as stable isotope tracers, isotope abundance measurements in nuclear chemistry and accurate determinations by isotope dilution mass spectrometry.

Determination of Ultra-trace Metal Impurities in High-purity Cadmium Using Inductively Coupled Plasma Mass Spectrometry after Matrix Separation with Anion Exchange Resin.

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.

Spectroscopic Characteristic and Analytical Capability of Ar-N2 Inductively Coupled Plasma in Axially Viewing Optical Emission Spectrometry.

The spectroscopic characteristics and analytical capability of argon-nitrogen (Ar-N2) inductively coupled plasma (ICP) in axially viewing optical emission spectrometry (OES) were examined and figures of merit were determined in the present study. The spectroscopic characteristics such as the emission intensity profile and the excitation temperature observed from the analytical zone of Ar-N2 ICP in axially viewing ICPOES, in order to elucidate the enhancement of the emission intensity of elements obtained in our previous study, were evaluated and compared to those of the standard ICP. The background and emission intensities of elements as well as their excitation behavior for both atom and ion lines were also examined. As results, a narrower emission intensity profile and an increased excitation temperature as well as enhancements for both background and emission intensities of elements, which could be due to the ICP shrunken as well as the enhancement of the interaction between the central channel of the ICP and samples introduced, were observed for Ar-N2 ICP in axially viewing OES. In addition, the elements with relatively higher excitation and ionization energies such as As, Bi, Cd, Ni, P, and Zn revealed larger enhancements of the emission intensities as well as improved limits of detection (LODs), which were also attributed to the enhanced interaction between Ar-N2 ICP and the samples. Since the Ar-N2 ICP could be obtained easily only by the addition of a small amount of N2 gas to the Ar plasma gas of the standard ICP and no optimization on the alignment between Ar-N2 ICP and the spectrometer in commercially available ICPOES instruments was needed, it could be utilized as simple and optional excitation and ionization sources in axially viewing ICPOES.

Effect of Long-time Heating for Polyvinyl Chloride and Polypropylene Resin Pellet Certified Reference Materials for Heavy Metal Analysis.

The effect of long-time heating for both polyvinyl chloride (PVC) and polypropylene (PP) resin pellet certified reference materials (CRMs) for heavy metal analysis, which contained Cd, Cr, Hg and Pb, was examined in the present study. The temperature of the drying oven was 80°C, which was used for drying these CRMs before analysis, and the long-time heating was carried out for up to 480 h. As a result, a relative decrease in mass of ca. 0.3% was observed for both CRMs. Moreover, a decrease in concentration of ca. 10% was observed for Cr, even though the concentrations for other elements did not change during the long-time heating. Since the chemical form of Cr was an organometallic compound with lower melting point, it was considered that concentration decreased due to the heat.