Quantification strategies for elemental imaging of biological samples using laser ablation-inductively coupled plasma-mass spectrometry

This review provides analysts with critical insights of current approaches for quantification by laser ablation-inductively coupled plasma-mass spectrometry in the field of elemental imaging. This encompasses both calibration strategies that have been used with success in imaging biological samples, as well as those with potential to improve analytical accuracy and precision if applied to imaging. Methods reviewed include the use of CRMs, laboratory prepared matrix matched standards, internal standardisation, online standard addition and a variety of novel approaches that makes elemental imaging accessible to a wider base of analysts. The importance of quantification and factors affecting its use in imaging will also be considered.     

Electrical and structural properties of poly (ethylene oxide)/silver triflate polymer electrolyte system dispersed with MgO nanofillers

Solvent-free films of poly (ethylene oxide)–silver triflate (PEO–AgCF₃SO₃)/MgO-based nanocomposite polymer electrolytes (PEO)₅₀AgCF₃SO₃–x wt.% MgO (x = 1, 3, 5, 7, and 10) obtained using solution casting technique were found to exhibit an appreciably good complexation of MgO nanofiller within the polymer electrolyte system and non-Debye type of relaxation as revealed by Fourier transform infrared and complex impedance analyses. Optimized filler (5 wt.% MgO) when incorporated into the polymer electrolyte resulted in a maximum electrical conductivity of 2 × 10⁻⁶ S cm⁻¹ in conjunction with a silver ionic transference number (t _Ag+) of 0.23 at room temperature (298 K). Detailed structural, thermal, and surface morphological investigation indicated a slight reduction in the degree of crystallinity owing to the addition of MgO nanofiller.     

Quantum Monte Carlo for the x-ray absorption spectrum of pyrrole at the nitrogen K-edge

Fixed-node diffusion Monte Carlo (FNDMC) is used to simulate the x-ray absorption spectrum of a gas-phase pyrrole molecule at the nitrogen K-edge. Trial wave functions for core-excited states are constructed from ground-state Kohn-Sham determinants substituted with singly occupied natural orbitals from configuration interaction with single excitations calculations of the five lowest valence-excited triplet states. The FNDMC ionization potential (IP) is found to lie within 0.3 eV of the experimental value of 406.1 ± 0.1 eV. The transition energies to anti-bonding virtual orbitals match the experimental spectrum after alignment of IP values and agree with the existing assignments.     

Resonant Rayleigh scattering from excitons in CdxZn1−xTe:ZnTe quantum wells: measurement of homogeneous linewidths

The technique of resonant Rayleigh scattering is used to determine the homogeneous linewidth across the inhomogeneously broadened exciton resonance in a Cd_0.25Zn_0.75Te/ZnTe multiple quantum well structure. An order of magnitude increase of the Rayleigh scattering signal over background is observed on tuning a narrow-band laser through the exciton resonance at low temperatures. Spectral and temporal measurements show the effect to be a true scattering process rather than luminescence. The interface and alloy fluctuations in the quantum well give rise to spatial fluctuations in the dielectric response of the system while the large exciton resonance causes strong enhancement of scattering. The homogeneous linewidth was calculated across the exciton resonance. The technique is compared with the dephasing and hole-burning techniques more commonly used in homogeneous linewidth measurements.