Matrix certified reference materials for environmental monitoring from the National Metrology Institute of Japan (NMIJ)

Matrix certified reference materials (CRMs) are playing an increasingly important role in environmental monitoring in Japan. The National Metrology Institute of Japan (NMIJ)/National Institute of Advanced Industrial Science and Technology (AIST) has been developing matrix CRMs for environmental monitoring since 2001, and has issued nine kinds of CRMs as NMIJ CRMs. The development of the CRMs was conducted in NMIJ in cooperation with candidate material producers. The isotope dilution mass spectrometry (IDMS) was principally adopted to give reliable certified values. Meanwhile, two or more analytical methods, whose levels of accuracy were well evaluated, were applied to avoid any possible analytical bias. Two typical certification processes, the certification of river water CRMs for trace element analysis and that of marine sediment CRMs for PCB and organochlorine pesticide analysis, are outlined as examples. Presented at -- “BERM-10” -- April 2006, Charleston, SC, USA.     

New molecular compound precursor for aluminum chemical vapor deposition

A new type of precursor for aluminum chemical vapor deposition (Al‐CVD) has been developed by mixing dimethylaluminum hydride (DMAH) and trimethylaluminum (TMA). The new precursor has proven itself to be effective for Al‐CVD, where a good selectivity between the Si and the SiO₂ mask, a 3.0 μΩ cm resistivity and a pure Al film with low C and O contamination levels (under 100 ppm) were achieved. Quadrupole mass and infrared absorption analysis have shown that the precursor contains a new molecular compound, consisting of a DMAH monomer and a TMA monomer. The mixture has lower viscosity than DMAH and can be easily bubbled for a stable precursor vapor supply. Copyright © 2000 John Wiley & Sons, Ltd.     

Simultaneous determination of a novel oral Janus kinase inhibitor ASP015K and its sulfated metabolite in rat plasma using LC‐MS/MS

A sensitive and selective liquid chromatography with tandem mass spectrometry (LC‐MS/MS) was developed for determining the concentrations of novel Janus kinase inhibitor ASP015K and its sulfated metabolite M2 in rat plasma. This method involves solid‐phase extraction (SPE) from 25 μL of rat plasma. LC separation was performed on an Inertsil PH‐3 column (100 mm L ×4.6 mm I.D., 5 µm) with a mobile phase consisting of 10 mM ammonium acetate and methanol under linear gradient conditions. Analytes were introduced to the LC‐MS/MS through an electrospray ionization source and detected in positive‐ion mode using selected reaction monitoring. Standard curves were linear from 0.25 to 500 ng/mL (r ≥0.9964). This assay enabled quantification of ASP015K and M2 at a concentration as low as 0.25 ng/mL in rat plasma. Validation data demonstrated that the method is selective, sensitive and accurate. Further, we also successfully applied this method to a preclinical pharmacokinetic study in rats. Copyright © 2014 John Wiley & Sons, Ltd.     

Surface Impedance Tensors of Textured Polycrystals

A formula for the surface impedance tensors of orthorhombic aggregates of cubic crystallites is given explicitly in terms of the material constants and the texture coefficients. The surface impedance tensor is a Hermitian second-order tensor which, for a homogeneous elastic half-space, maps the displacements given at the surface to the tractions needed to sustain them. This tensor plays a fundamental role in Stroh's formalism for anisotropic elasticity. In this paper we account for the effects of crystallographic texture only up to terms linear in the texture coefficients and give an explicit formula for the terms in the surface impedance tensor up to those linear in the texture coefficients. This revised version was published online in June 2006 with corrections to the Cover Date.     

Magnetic phase transition in ɛ-In x Fe2 − x O3 nanowires

This paper reports on a study of magnetic properties of ordered arrays of ?-In _x Fe_{2 ? x} O₃ (x = 0.24) nanowires possessing a high room-temperature coercive force of 6 kOe. Lowering the temperature below 190 K brings about a sharp decrease of the coercive force and magnetization of nanowires driven by the magnetic phase transition from the ferrimagnetic into antiferromagnetic phase. The transition is accompanied by a decrease of the magnetic anisotropy constant, which accounts for the anomalous frequency dependence of the position of the maximum in the temperature dependence of dynamic magnetic susceptibility. In the low-temperature phase, a spin-flop transition in the magnetic field of 28 kOe has been observed at T = 2 K. Lines related to the high-temperature hard-magnetic and low-temperature phases have been identified in electron spin resonance spectra of the nanowires. A line lying near zero magnetic field and evolving from the nonresonant signal related to the microwave magnetoresistance of the sample has also been detected.     

Calcium tungstate coprecipitation for removal of Sr interference with determination of Rb by ID-ICP-MS

A coprecipitation method using calcium tungstate was developed to remove ⁸⁷Sr isobaric interference with ⁸⁷Rb prior to measurement of Rb by ID-ICP-MS. Precipitation of calcium tungstate was obtained by adding Ca(NO₃)₂ solution and (NH₄)₂WO₄ solution to the sample, where (NH₄)₂WO₄ was added more than the stoichiometric proportion to precipitate Ca(NO₃)₂ completely and remove Sr effectively. Furthermore, in order to reduce matrix burden to the ICP-MS instrument, the residual (NH₄)₂WO₄ was removed by adding conc. HNO₃. Prior to the application, thorough purification of coprecipitant reagent was carried out to reduce the blank. The effectiveness of the present method was verified by analyzing two brown rice flour certified reference materials (CRMs), NIES CRM 10a and NIES CRM 10b. Finally, the present method was applied to the measurement of Rb in a white rice flour RM sample being developed by National Institute of Metrology of Japan.     

Monitoring of morphology and physical properties of cultured cells using a micro camera and a quartz crystal with transparent indium tin oxide electrodes after injections of glutaraldehyde and trypsin

For investigating the effects of chemical stimulation to cultured cells, we have developed a quartz crystal sensor system with a micro charge-coupled device (CCD) camera that enables microphotograph imaging simultaneously with quartz crystal measurement. Human hepatoma cell line (HepG2) cells were cultured on the quartz crystal through a collagen film. The electrode of the quartz crystal was made of indium tin oxide (ITO) transparent electrodes that enable to obtain a transparent mode photograph. Glutaraldehyde and trypsin were injected to the chamber of the cells, respectively. The response of the quartz crystal was monitored and microphotographs were recorded, and the resonance frequency and resonance resistance were analyzed with an F-R diagram that plotted the resonance frequency and resonance resistance. In the case of the glutaraldehyde injection, the cells responded in two steps that included the fast response of the cross-linking reaction and the successive internal change in the cells. In the case of the trypsin injection, the responses included two processes. In the first step, cell adhesion factors were cleaved and the cell structure became round, and in the next step, the cells were deposited on the quartz crystal surface and the surface of the cells was directly in contact with the quartz crystal surface.     

Theoretical analysis of the intermolecular interaction effects on the excitation energy of organic pigments: solid state quinacridone

Quinacridones (QAs) are organic hydrogen-bonded pigments, which are yellow in solution and become reddish to violet in solid phase depending on the crystal structure. We have carried out regular and fragment molecular orbital (FMO) based time-dependent density functional theory (TDDFT) calculations of the alpha (I), beta, and gamma crystalline phases of QA to examine the origin of the spectral shift in the solid phase. On the basis of the TDDFT calculations, we have found that the spectral shift from gas to solid phase in QA is dominated by the interplay of the structural deformation, electrostatic potential (crystal field), and intermolecular interactions, and each contribution is of the same order of magnitude. The spectral shift induced by the structural deformation is mainly caused by the stretch of the CO bond. The individual intermolecular interactions contribute to bathochromic and hypsochromic shifts depending on the spatial orientation, and their sums result in the bathochromic shift overall.