This blog has been set up for editors, reviewers, authors and readers of Elsevier's Analytical Chemistry Journals - all of which can be seen below. It will be updated from Monday to Friday with general news and announcements concerning the titles listed on this page. It should be noted that the views or claims made in the news items and feeds are not necessarily those of the Publisher.
World Congress on Biosensors 2014
Biosensors 2014
Monday, 24 December 2012
Just Published: Spectrochimica Acta Part B: Atomic Spectroscopy
A new issue of this journal has just
been published. To see abstracts of the papers it contains (with links through
to the full papers) click here:
Available online 21 December
2012 Publication year: 2012 Source:Spectrochimica Acta Part B:
Atomic Spectroscopy
Home-based collection protocols for clinical
specimens are actively pursued as a means of improving life quality of patients
that require frequent controls, such as patients with metallic prosthesis, for
whom monitoring the evolution of Mo and Ti in biological fluids may play a
decisive role to detect prosthesis mal-functioning. The collection of biological
fluids on clinical filter papers provides a simple way to implement these
protocols. This work explores the potential of solid sampling high-resolution
continuum source graphite furnace atomic absorption spectrometry for the
simultaneous and direct determination of Mo and Ti in urine, after its
deposition onto clinical filter paper, giving rise to a dried urine spot. The
approach used for depositing the sample was found crucial to develop a
quantitative method, since the filter paper acts as a chromatographic support
and produces a differential distribution of the target analytes. Furthermore,
the high spreading of urine onto a filter paper results in a small amount of
urine per surface unit, and thus, ultimately, in lack of sensitivity. In order
to circumvent these problems, the use of an alternative approach based on the
use of pre-cut 17x19 mm filter paper pieces onto which larger amounts of sample
(500 μL) can be retained by single deposition was proposed and evaluated. In
this way, an approximately 12-fold increase in sensitivity and a more
homogeneous distribution of the target analytes were obtained, permitting the
development of a quantification strategy based on the use of matrix-matched
urine samples of known analyte concentrations, which were subjected to the same
procedure as the samples. Accuracy of this method, which provides LODs of
1.5μgL-1 for Mo and 6.5μgL-1 for Ti, was demonstrated
after analysis of urine reference materials. Overall, the performance of the
method developed is promising, being likely suitable for determination of other
analytes in dried urine spots.
Highlights
► deposition of urine on clinical filters is a
simple way to implement home-base collection procedures to monitor patient's
evolution ► solid sampling HR CS GFAAS is investigated for the direct
determination of Mo and Ti, used as biomarkers to detect prosthesis
malfunctioning, in urine dried spots; ► the way in which the sample is deposited
in the filter is key to ensure sufficient sensitivity and to avoid
chromatographic effects; ► use of matrix-matched urine standards for calibration
is proposed, permitting achieving accurate results and LODs of a few
μgL-1;
Available online 21 December
2012 Publication year: 2012 Source:Spectrochimica Acta Part B:
Atomic Spectroscopy
Interferences of selected hydride forming elements
(As, Sb, Bi, Se and Sn) on lead determination by hydride generation atomic
absorption spectrometry were extensively studied in both on-line atomization and
preconcentration (collection) modes. The commonly used on-line atomization mode
was found free of significant interferences, whereas strong interference from Bi
was observed when employing the preconcentration mode with plumbane collection
in a quartz trap-and atomizer device. Interference of Bi seems to take place in
the preconcentration step. Interference of Bi in the collection mode cannot be
reduced by increased hydrogen radical amount in the trap and/or the atomizer.
Highlights
► Interference study on Pb determination by
in-atomizer trapping was performed for the first time. ► Bi was found as a
severe interferent in the preconcentration mode (Pb:Bi ratio 1:100). ► No
interference was found in the on-line atomization (no preconcentration). ► Bi
interference occurs during preconcentration.
Available online 20 December
2012 Publication year: 2012 Source:Spectrochimica Acta Part B:
Atomic Spectroscopy
This article summarizes measurements and analysis of
hydrogen Balmer series atomic lines following laser-induced optical breakdown.
Electron number density on the order of 1 × 1025 m−3 can
be measured using H α Stark width and shift in the analysis of breakdown plasma
in 1 to 1.3 × 105 Pa, gaseous hydrogen. The H β line can be utilized
for electron number density up to 7 × 1023 m−3. The
historic significance is elaborated of accurate H β measurements. Electron
excitation temperature is inferred utilizing Boltzmann plot techniques that
include H γ atomic lines and further members of the Balmer series. Laser
ablation of aluminium is discussed in view of limits of application of the
Balmer series. H β and H γ lines show presence of molecular carbon in a 2.7 and
6.5 × 105 Pa, expanding methane flow. Diagnostic of such diatomic
emission spectra is discussed as well. Laser-induced breakdown spectroscopy
historically embraces elemental analysis, or atomic spectroscopy, and to a
lesser extent molecular spectroscopy. Yet occurrence of superposition spectra in
the plasma decay due to recombination or due to onset of chemical reactions
necessitates consideration of both atomic and molecular emissions following
laser-induced optical breakdown. Molecular excitation temperature is determined
using so-called modified Boltzmann plots and fitting of spectra from selected
molecular transitions. The primary interest is micro-plasma characterization
during the first few micro-seconds following optical breakdown, including
shadowgraph visualizations.
Graphical abstract
Highlights
► Electron density
measurements in plasma using H-alpha and H-beta lines; ► Analysis of recorded
data using accepted theories; ► Limitations of hydrogen Balmer series in study
of laser-induced optical breakdown; ► Analysis of atomic and molecular
superposition spectra; ► Computed atomic profiles and diatomic molecular spectra
using line-strength-files.
Available online 7 December
2012 Publication year: 2012 Source:Spectrochimica Acta Part B:
Atomic Spectroscopy
In this work, the possibility of using Laser-Induced
Breakdown Spectrometry (LIBS) combined with liquid–liquid microextraction
techniques is evaluated as a simple and fast method for trace elemental
analysis. Two different strategies for LIBS analysis of manganese contained in
microdroplets of extraction solvent (Triton X-114) are studied: (i) analysis by
direct laser irradiation of microdroplets; and (ii) analysis by laser
irradiation of microdroplets dried on metallic substrates (surface-enhanced LIBS
— SENLIBS). Experiments were carried out using synthetic samples with different
concentrations of manganese in a 10% w/w Triton X-114 matrix. The analysis by
direct laser irradiation of microdroplets showed low precision, sensitivity and
poor linearity across the concentration range evaluated (R2
<0.95). On the other hand, the SENLIBS method of analysis improved the
sensitivity, the precision and the linearity of the calibration curve with
respect to the direct analysis of microdroplets. In comparison with experimental
results obtained by direct analysis, SENLIBS also allowed several replicate
measurements to be carried out in a single microdroplet. The limit of detection
obtained was 6μgg−1 of Mn.
Highlights
► LIBS combined with microextraction procedures for
trace analysis is proposed. ► The proposed combination depends on LIBS ability
to analyze sample microvolumes. ► A surface-enhanced LIBS methodology for
microdroplet analysis was evaluated. ► Results indicate this combination to be
promising for trace analysis in liquids.
Available online 7 December
2012 Publication year: 2012 Source:Spectrochimica Acta Part B:
Atomic Spectroscopy
The presence of self-absorption of emission lines is
usually an undesired effect in Laser Induced Breakdown Spectroscopy because it
introduces non linear effects in the growth of line intensity versus the
concentration of the emitting species. Several methods have been proposed in
recent years for identifying and quantifying self-absorption in the emission
spectra. After this diagnostic stage, the lines affected by self-absorption are
usually disregarded; otherwise, appropriate corrective factors are applied to
their intensity before the utilization for analytical purposes. Changing the
point of view, this paper remarks as self-absorption can provide useful
information for analyzing the composition of laser-induced plasmas and for their
characterization. Whenever the extent of self-absorption is quantified, in fact,
the optical depth of the line can be rapidly calculated; then, for plasmas in
local thermodynamic equilibrium conditions, the columnar density of the emitting
species can be derived. Assuming the plasma homogeneity, the concentration ratio
between different elements can be obtained. Moreover, in particular cases, the
columnar densities can be used to calculate the plasma temperature and the
absolute number densities of plasma species. Some applications of the method are
reported in the paper and potentialities and limitations are discussed.
Highlights
► A method for LIBS plasma characterization based on
self absorption is presented. ► It allows to calculate absolute columnar number
densities of plasma species. ► It allows also to calculate plasma temperature
and analytical composition. ► The method does not rely on the spectral
calibration of the detection apparatus.
Available online 5 December
2012 Publication year: 2012 Source:Spectrochimica Acta Part B:
Atomic Spectroscopy
Chlorine is a main elemental component of atmospheric
particulate matter (APM). The knowledge of the chemical form of chlorine is of
primary importance for source apportionment and for estimation of health effects
of APM. In this work the applicability of high-resolution wavelength dispersive
proton induced X-ray emission (PIXE) spectroscopy for chemical speciation of
chlorine in fine fraction atmospheric aerosols is studied. A Johansson-type
crystal spectrometer with energy resolution below the natural linewidth of Cl K
lines was used to record the high-resolution Kα and Kβ proton induced spectra of
several reference Cl compounds and two atmospheric aerosol samples, which were
collected for conventional PIXE analysis. The Kα spectra which refers to the
oxidation state, showed very minor differences due to the high electronegativity
of Cl. However, the Kβ spectra exhibited pronounced chemical effects which were
significant enough to perform chemical speciation. The major chlorine component
in two fine fraction aerosol samples collected during a 2010 winter campaign in
Budapest was clearly identified as NaCl by comparing the high-resolution Cl Kβ
spectra from the aerosol samples with the corresponding reference spectra. This
work demonstrates the feasibility of high-resolution PIXE method for chemical
speciation of Cl in aerosols.
Highlights
► Chemical specation of Cl in aerosol samples by
high resolution PIXE spectroscopy. ► Fine structure of Kα and Kβ lines of
reference compounds and APM samples was given. ► Kα spectra were well aligned
with each other confirming the same Cl oxidation state. ► Pronounced chemical
effects were observed in the Kβ spectra. ► We showed that chemical speciation of
Cl was possible on thin aerosol samples.
Thanks for sharing your data Chemistry Homework Help
ReplyDelete