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.
Publication year:
2012 Source:Analytica Chimica Acta, Volume 753 Xuemei Wang, Jiyan
Liu, Aifeng Liu, Qian Liu, Xinzhen Du, Guibin Jiang Two kinds of mesoporous
cellular foams (MCFs), including mesoporous silica materials (MCF-1) and phenyl
modified mesoporous materials (Ph-MCF-1), were synthesized and for the first
time used as fiber-coating materials for solid-phase microextraction (SPME). By
using stainless steel wire as the supporting core, four types of fibers were
prepared by sol–gel method and immobilized by epoxy-resin method. To evaluate
the performance of the home-made fibers for SPME, seven brominated flame
retardants (BFRs), including tetrabromobisphenol A (TBBPA), tetrabromobisphenol
S (TBBPS) and related compounds were selected as analytes. The main parameters
that affect the extraction and desorption efficiencies, such as extraction
temperature, extraction time, desorption time, stirring rate and ionic strength
of samples were investigated and optimized. The optimized SPME coupled with high
performance liquid chromatography (HPLC) was successfully applied to the
determination of the seven BFRs in water samples. The linearity range was from
5.0 to 1000μgL−1 for each compound except TBBPS (from 1.0 to
1000μgL−1), with the correlation coefficients (r 2)
ranging from 0.9993 to 0.9999. The limits of detection of the method were
0.4–0.9μgL−1. The relative standard deviations varied from 1.2 to
5.1% (n =5). The repeatability of fiber-to-fiber and batch-to-batch was 2.5–6.5%
and 3.2–6.7%. The recoveries of the BFRs from aqueous samples were in the range
between 86.5 and 103.6%. Compared with three commercial fibers (100μm PDMS, 85μm
PA and 65μm PDMS/DVB), the MCFs-coated fiber showed about 3.5-fold higher
extraction efficiency.
Graphical abstract
Graphical abstract Highlights
►
Two novel mesoporous cellular foams were synthesized and used as SPME coating. ►
Four SPME fibers were prepared by sol–gel technology and immobilized resin
method. ► New coating had excellent extraction ability to seven brominated flame
retardants.
Publication year:
2012 Source:Analytica Chimica Acta, Volume 753 Chad P. Satori,
Vratislav Kostal, Edgar A. Arriaga The analysis of isolated organelles is one
of the pillars of modern bioanalytical chemistry. This review describes recent
developments on the isolation and characterization of isolated organelles both
from living organisms and cell cultures. Salient reports on methods to release
organelles focused on reproducibility and yield, membrane isolation, and
integrated devices for organelle release. New developments on organelle
fractionation after their isolation were on the topics of centrifugation,
immunocapture, free flow electrophoresis, flow field-flow fractionation,
fluorescence activated organelle sorting, laser capture microdissection, and
dielectrophoresis. New concepts on characterization of isolated organelles
included atomic force microscopy, optical tweezers combined with Raman
spectroscopy, organelle sensors, flow cytometry, capillary electrophoresis, and
microfluidic devices.
Graphical abstract
Graphical abstract Highlights
►
Advancements in organelle release. ► New approaches to fractionate organelles. ►
Updates on new techniques to characterize isolated organelles.
Publication year:
2012 Source:Analytica Chimica Acta, Volume 753 Caitlin N. Rinke,
Mary R. Williams, Christopher Brown, Matthieu Baudelet, Martin Richardson,
Michael E. Sigman A method is described for performing discriminant analysis
in the presence of interfering background signal. The method is based on
performing target factor analysis on a data set comprised of contributions from
analyte(s) and interfering components. A library of data from representative
analyte classes is tested for possible contributing factors by performing
oblique rotations of the principal factors to obtain the best match, in a
least-squares sense, between test and predicted vectors. The degree of match
between the test and predicted vectors is measured by the Pearson correlation
coefficient, r, and the distribution of r for each class is determined. A
Bayesian soft classifier is used to calculate the posterior probability based on
the distributions of r for each class, which assist the analyst in assessing the
presence of one or more analytes. The method is demonstrated by analyses
performed on spectra obtained by laser induced breakdown spectroscopy (LIBS).
Single and multiple bullet jacketing transfers to steel and porcelain substrates
were analyzed to identify the jacketing materials. Additionally, the metal
surrounding bullet holes was analyzed to identify the class of bullet jacketing
that passed through a stainless steel plate. Of 36 single sample transfers, the
copper jacketed (CJ) and non-jacketed (NJ) class on porcelain had an average
posterior probability of the metal deposited on the substrate of 1.0. Metal
jacketed (MJ) bullet transfers to steel and porcelain were not detected as
successfully. Multiple transfers of CJ/NJ and CJ/MJ on the two substrates
resulted in posterior probabilities that reflected the presence of both
jacketing materials. The MJ/NJ transfers gave posterior probabilities that
reflected the presence of the NJ material, but the MJ component was mistaken for
CJ on steel, while non-zero probabilities were obtained for both CJ and MJ on
porcelain. Jacketing transfer from a bullet to steel as the projectile passed
through the steel also proved difficult to analyze. Over 50% of the samples left
insufficient transfer to be identified. Transfer from NJ and CJ jacketing was
successfully identified by posterior probabilities greater than 0.8.
Graphical abstract
Graphical abstract Highlights
► A
novel background-independent soft classification method is described. ► Target
factor analysis is combined with Bayesian decision theory. ► Target factors are
taken from a library of target analytes. ► Trace metal transfers to complex
backgrounds are analyzed by LIBS. ► The method is shown to be both conservative
and accurate.
Publication year:
2012 Source:Analytica Chimica Acta, Volume 753 Jingjing Wu, Huaqin
Chu, Zhanlong Mei, Yi Deng, Feng Xue, Lei Zheng, Wei Chen A one-step
electrochemical aptasensor using the thiol- and methylene blue- (MB-)
dual-labeled aptamer modified gold electrode for determination of ochratoxin A
(OTA) was presented in this research. The aptamer against OTA was covalently
immobilized on the surface of the electrode by the self-assembly effect and used
as recognition probes for OTA detection by the binding induced folding of the
aptamer. Under the optimal conditions, the developed electrochemical aptasensor
demonstrated a wide linear range from 0.1pgmL−1 to
1000pgmL−1 with the limit of detection (LOD) of
0.095pgmL−1, which was an extraordinary sensitivity compared with
other common methods for OTA detection. Moreover, as a practical application,
this proposed electrochemical aptasensor was used to monitor the OTA level in
red wine samples without any special pretreatment and with satisfactory results
obtained. Study results showed that this electrochemical aptasensor could be a
potential useful platform for on-site OTA measurement in real complex samples.
Graphical abstract
Graphical abstract Highlights
►
One-step electrochemical aptasensor for OTA detection. ► Rapid and
ultrasensitive OTA detection with LOD of 0.095pgmL−1 in less than
15min. ► Successful application of the electrochemical aptasensor in OTA spiked
samples. ► Providing a potential tool for on-site quality control of OTA related
pollutions.
Publication year:
2012 Source:Analytica Chimica Acta, Volume 753 Shagayegh Saadati,
Abdollah Salimi, Rahman Hallaj, Amin Rostami A novel, simple and facile layer
by layer (LBL) approach is used for modification of glassy carbon (GC) electrode
with multilayer of catalase and nanocomposite containing
1-(3-Aminopropyl)-3-methylimidazolium bromide (amine terminated ionic liquid
(NH2-IL)) and titanium nitride nanoparticles (TiNnp). First a thin layer of
NH2-IL is covalently attached to GC/TiNnp electrode using electro-oxidation
method. Then, with alternative self assemble positively charged NH2-IL and
negatively charged catalase a sensitive H2O2 biosensor is constructed, whose
response is directly correlated to the number of bilayers. The surface coverage
of active catalase per bilayer, heterogeneous electron transfer rate constant (k
s) and Michaelis–Menten constant (K M) of immobilized catalase were
3.32×10−12 molcm−2, 5.28s−1 and 1.1mM,
respectively. The biosensor shows good stability, high reproducibility, long
life-time, and fast amperometric response with the high sensitivity of
380μAmM−1 cm−2 and low detection limit of 100nM at
concentration range up to 2.1mM.
Graphical abstract
Graphical abstract Highlights
►
Catalase and amine-terminated ionic liquid were immobilized to GC/TiNnp with LBL
assembly method. ► First a thin layer of NH2-IL is covalently attached to
GC/TiNnp electrode using electro-oxidation. ► With alternative assemble of IL
and catalase with positive and negative charged, multilayer was formed. ►
Immobilized catalase shows excellent electrocatalytic activity toward H2O2
reduction. ► Biosensor response is directly correlated to the number of
bilayers.
Publication year:
2012 Source:Analytica Chimica Acta, Volume 753 Virginie Aumond,
Matthieu Waeles, Pascal Salaün, Kristoff Gibbon-Walsh, Constant M.G. van den
Berg, Pierre-Marie Sarradin, Ricardo D. Riso A rapid electrochemical
stripping chronopotentiometric procedure to determined sulfide in unaltered
hydrothermal seawater samples is presented. Sulfide is deposited at −0.25V (vs
Ag/AgCl, KCl 3M) at a vibrating gold microwire and then stripped through the
application of a reductive constant current (typically −2μA). The hydrodynamic
conditions are modulated by vibration allowing a short deposition step, which is
shown here to be necessary to minimize H2S volatilization. The limit of
detection (LOD) is 30nM after a deposition step of 7s. This LOD is in the same
range as the most sensitive cathodic voltammetric technique using a mercury drop
electrode and is well below those reported previously for other electrodes
capable of being implemented in situ.
Publication year:
2012 Source:Analytica Chimica Acta, Volume 753 Xiao Qing Yan, Qian
Jin Shen, Xiao Ran Zhao, Hai Yue Gao, Xue Pang, Wei Jun Jin For the first
time, halogen-bonding interaction is utilised in the solid phase extraction of
perfluorinated iodoalkane (PFI). Nine PFIs, as model analytes, were tested, and
analyses by UV, 19F NMR and Raman spectroscopies demonstrate that the
PFIs are extracted by a strong anion exchange (SAX) sorbent from n-hexane due to
the CI⋯Cl− halogen-bonding interactions. The results also show that
the adsorptivities of SAX for the diiodoperfluoro-alkanes (diiodo-PFIs) were
much stronger than those for the perfluoroalkyl iodides (monoiodo-PFIs).
Specifically, the recoveries for 1,6-diiodoperfluorohexane and
1,8-diiodoperfluorooctane were higher than 80% when 100mL of sample spiked with
a 5ngmL−1 analyte mixture was extracted. Interestingly, SAX had no
adsorption for hexafluorobenzene at all, which is known to be unable to form a
halogen bond with Cl−. The analytical performance of the halogen
bond-based SPE-GC–MS method for the diiodo-PFIs was also examined in soil
samples. The sorbent SAX enabled the selective extraction of four diiodo-PFIs
successfully from soil samples. The recoveries of the diiodo-PFIs extracted from
5g soil sample at the 100ngg−1 spike level were in the range of
73.2–93.8% except 26.8% for 1,2-diiodoperfluoroethane. The limit of detection
varied from 0.02 to 0.04ngg−1 in soil samples. Overall, this work
reveals the great application potential of halogen bonding in the field of solid
phase extraction to selectively extract compounds with strong halogen-bonding
abilities.
Graphical abstract
Graphical abstract Highlights
►
Halogen bonding (XB) is firstly utilised in solid phase extraction. ► The
perfluorinated iodine alkanes can be extracted by CI⋯Cl− halogen
bonding. ► The CI⋯Cl− halogen bond is well characterised by
spectroscopy methods. ► The analytes with strong halogen-bonding abilities can
be selectively extracted.
Publication year:
2012 Source:Analytica Chimica Acta, Volume 753 Xiaowei Wang, Li
Lin, Tiangang Luan, Lihua Yang, Nora F.Y. Tam A sample preparation method for
the determination of hydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) in
sediment samples was developed using gas chromatography–mass spectrometry
(GC–MS). Dispersive liquid–liquid microextraction (DLLME) with derivatization
was performed following the subcritical water extraction (SWE) that provided
which was provided by accelerated solvent extraction (ASE). Several important
parameters that affected both SWE extraction and DLLME, such as the selection of
organic modifier, its volume, extraction temperature, extraction pressure and
extraction time were also investigated. High sensitivity of the hydroxylated
PAHs derivatives by N-(tert-butyldimethylsilyl)-N-methyl-trifluoroacetamide
(MTBSTFA) could be achieved with the limits of detection (LODs) ranging from
0.0139 (2-OH-nap) to 0.2334μgkg−1 (3-OH-fluo) and the relative
standard deviations (RSDs) between 2.81% (2-OH-phe) and 11.07% (1-OH-pyr).
Moreover, the proposed method was compared with SWE coupled with solid phase
extraction (SPE), and the results showed that ASE–DLLME was more promising with
recoveries ranging from 57.63% to 91.07%. The proposed method was then applied
to determine the hydroxylated metabolites of phenanthrene in contaminated
sediments produced during the degradation by two PAH-degraders isolated from
mangrove sediments.
Graphical abstract
Graphical abstract Highlights
► We
combine subcritical water extraction (SWE) with dispersive liquid–liquid
microextraction (DLLME). ► Subcritical water is used as the extraction solvent
for SWE and the sample solution for the following DLLME. ► Acetonitrile is used
as the organic modifier for SWE and disperser solvent for DLLME in succession. ►
We examine changes of OH-PAHs during the degradation by
microorganism.
Publication year:
2012 Source:Analytica Chimica Acta, Volume 753 Liting Liu, Ying
Zhang, Lei Zhang, Guoquan Yan, Jun Yao, Pengyuan Yang, Haojie Lu Although the
specific profiling of endogenous glycopeptides in serum is highly inclined
towards the discovery of disease biomarkers, studies on the endogenous
glycopeptides (glycopeptidome) have never been conducted because of several
factors. These factors include the high dynamic range of serum proteins, the
inadequacy of traditional sample preparation techniques in proteomics for
low-molecular-weight (LMW) proteins, and the relatively low abundances of
glycopeptides. Boronic acid-functionalized mesoporous silica was synthesized in
this study to overcome the limitations of the state-of-the-art methods for
glycopeptidome research. The boronic acid-functionalized mesoporous silica
exhibited excellent selectivity by analyzing glycopeptides in the mixture of
glycopeptides/non-glycopeptides at molar ratio of 1:100, extreme sensitivity
(the limit of detection was at the fmol level), good binding capacity
(40mgg−1), as well as the high post-enrichment recovery of
glycopeptides (up to 88.10%). The as-prepared material possessing both
glycopeptide-suitable pore size and glycopeptide-specific selectivity has shown
special capability for enriching the endogenous glycopeptides. Fifteen unique
glycosylation sites mapped to 15 different endogenous glycopeptides were
identified in rat serum. The established protocol revealed for the first time
the rat serum glycopeptidome.
Graphical abstract
Graphical abstract Highlights
A highly ordered boronic
acid-functionalized mesoporous silica was synthesized and applied for the
revelation of rat serum glycopeptidome for the first time. ► A highly ordered boronic acid-functionalized mesoporous
silica was synthesized. ► The as-prepared material possessed both
glycopeptide-suitable pore size and glycopeptide-specific selectivity. ► The
as-prepared material showed highly efficient ability for enrichment of
endogenous glycopeptides from serum. ► Rat serum glycopeptidome was reveled for
the first time.
Sheldon
Manufacturing, Inc. introduces the SHEL LAB Model 2428H, the newest addition to
its large capacity CO2 incubator line. (http://www.shellab.com/store/categories/large-co2-incubator/)
This 27 cubic foot incubator features active humidity control up to 95%.
“The three most
critical incubator components that ensure high yields in cell culture are
humidity, CO2 and temperature uniformity” states Dan Sheldon,
President of Sheldon Manufacturing, Inc. “Not only does this unit have
exceptional CO2 and temperature uniformity, it also includes a user
controllable humidity system that is more accurate and responsive to door
openings than a traditional water pan humidity system."
Compared
to water pan humidity generation, the 2428H humidity system provides less
evaporation of culture media and eliminates a potential source for
contamination.
The
2428H also has a heated glass door that minimizes condensation, another
potential source for contamination. This triple-paned glass door allows easy
viewing of samples without having to open the incubator door, so samples can
thrive in the stable environment within the chamber. The 2428H SHEL LAB
Humidified CO2 Incubator (http://www.shellab.com/store/lab-products/2428H)
also features an antimicrobial copper drain.
The
2428H carbon dioxide incubator uses a gentle horizontal air flow heating system
to obtain superior temperature uniformity and quick temperature recovery after
door openings. This airflow system minimizes drying and disturbing sample
conditions. The CO2 is accurately controlled with an IR sensor,
providing overall CO2 stability and recovery after door openings.
The 2428H is
available through SHEL LAB distribution partners and at www.shellab.com
Asynt Ltd. in conjunction with Innovative Physical Organic Solutions (IPOS), a
research group based within the University of Huddersfield, UK, have cooperated
over the last 2 years to develop a new generation of chemical reactor.
By better understanding and improving the flow and thermal dynamics of the
Asynt ReactoMate system the co-operation is able to now produce reactors that
offer ultimate mixing performance. The benefits of this development for
chemists will be simpler process development and scale-up, faster reactions,
better reproducibility and improved selectivity.
Martyn Fordham, Managing Director of Asynt Ltd. commented "We were pleased
to cooperate with IPOS on this development because of their considerable
expertise in chemical engineering and experience in advising chemists on
scaling reactions that were often rate limited by poor mixing". He added
"At the start of our cooperation - Asynt ReactoMate reaction systems
as with all of our competitors did not offer optimised mixing. Today
however, we can offer customers the option to use ReactoMate to scale
chemistries with well designed mixing by IPOS. This consideration has
proven especially important when reaction chemistries are exothermic for
example".
Dr Nicholas Powles, a Senior Research Fellow at IPOS commented "The
complexities associated with optimising and scaling-up laboratory reactions are
of critical importance in industrial process development. Our
co-operation with Asynt will help commercialise the essential tools and
'know-how' for efficient process understanding and optimisation".
Asynt is a leading supplier of affordable products, consumables and services
for chemists in industry and academia. With staff of trained chemists -
Asynt is able to draw upon this in-depth applications knowledge to provide a
high level of customer support for its DrySyn Heating Blocks, Controlled Lab
Reactors, Synthesis Tools, Evaporators, Circulators, Temperature Control
Systems, Vacuum Pumps and Laboratory Safety Equipment.
IPOS is a research group based within the Department of Chemical and Biological
Sciences at the University of Huddersfield (UK). The primary focus of IPOS is
delivery of external customer contracts. The group consists of a team of highly
skilled, industrially experienced chemists specialising in the application of
physical organic chemistry towards efficient optimisation of chemical
processes. It is the aim of IPOS to provide these services on a contract basis
to the chemical industry as a cost-effective means of process development.
For further information about ReactoMate Reactors with optimised mixing
performance please contact Asynt on +44-1638-781709 or sales@asynt.com. For further information
about IPOS please visit http://www-old.hud.ac.uk/ipos/
The FlowSyn™ range of integrated, flow reactor systems from Uniqsis Ltd. has
been designed to handle everything from homogeneous single reactions to
complex, multi-reagent reactions. A range of optional gas addition, microwave,
low temperature and binary pump (4-channel) modules further enhance the
operational versatility of the FlowSyn system.
Flow chemistry in micro-reactors has many advantages over batch processing
notably better reproducibility and scalability, improved yields and fewer
problems with unstable intermediates or exothermic reactions.
Developed by chemists for chemists, the Uniqsis FlowSyn system is available
with the widest range of reactors (2 - 60ml) in a choice of inert materials
including stainless steel, Hastelloy®, PFA, PTFE or even Copper. As a
consequence the FlowSyn System is able to perform an unmatched range of
chemistries. Reactions requiring the use of strong acids such as nitric acid
(nitrations) and powerful organometallic bases such as butyl lithium
(metallations) are now routinely possible. A unique 2- or 3-channel
borosilicate glass mixer chip reactor enables the FlowSyn system to undertake
high throughput applications, fast mixing dependent reactions and even highly exothermic
reactions requiring temperature control.
Within the FlowSyn system, two high pressure pumps operating at up to 100 bar
(1400 psi) deliver reagents, via a mixer, into electrically heated flow
reactors. Back pressure regulators pressurise the system, allowing solvents to
be superheated to a maximum of 260°C*.
Reaction outputs from the FlowSyn system can be fractionated or optimised at
steady state, after which the system automatically flushes itself ready for the
next experiment. The whole process, from start to finish, is controlled using
the highly intuitive integrated FlowSyn control interface.
To find out more about how FlowSyn Continuous Flow Chemistry Systems can
enhance your chemical syntheses please visit www.uniqsis.com/paFlowSystem.aspx
or contact Uniqsis now on +44-845-864-7747 / info@uniqsis.com.
Publication year:
2012 Source:Microchemical Journal, Volume 105 Anita Morris, Srujana
Beeram, Carey J. Hardaway, Joel C. Richert, Joseph Sneddon Crawfish shells
are an abundant waste product that has the potential to remediate contaminated
bodies of water. This study demonstrates that ground crawfish shell could be
used as an effective biosorbent material for the treatment of chromium in
contaminated aqueous solutions. Phase I experiments determined that the
adsorption was completed within 2h. For the time periods examined it could be
concluded that the maximum chromium adsorption occurs within the first 2h. Phase
II experiments demonstrated that chromium adsorption increased with sample
volume and concentration, however the efficiency decreased with increasing
sample volume for the relative high concentrations of chromium. Phase III
experiments showed that chitin is a major constituent for biosorption of
chromium and likely other metals in crustacean species including crawfish.
Salinity experiments showed that salt (sodium chloride) at the 30ppt (parts per
thousand) concentrations does not affect the crawfish shell ability to adsorb
chromium. The pH was the most important factor for chromium adsorption by the
crawfish powder. Chromium adsorption increased with increasing pH. The presence
of lead ions did not significantly interfere with the adsorption of chromium
ions onto the crawfish shell powder for the relatively high concentrations
examined. However, for relatively low concentrations the chromium adsorption was
somewhat suppressed by the lead ions.
Highlights
► Use of crawfish shells for biosorption ► Uptake
of chromium in solution in less than 2h ► pH affected uptake. ► Salt at ppt and
lead ions had no effect on uptake.
Publication year:
2012 Source:Microchemical Journal, Volume 105 Michael Krachler,
Stefaan Van Winckel, Mariangela Cardinale, Brian Lynch, Tsuyoshi Murakami An
analytical procedure for the reliable determination of the alkaline elements Na,
K, and Li in radioactive samples was developed and validated. To this end, a
high efficiency, desolvating nebulizer (Apex E) was coupled to a commercial high
resolution ICP-OES instrument operated at 1000W. Because of their radioactive
nature, all investigated samples were handled in appropriate glove boxes
operated in under-pressure, following strict safety and security procedures.
After optimization of the ICP-OES operational parameters, detection limits
(LODs) of 0.15μg/L, 0.8μg/L, and 1.3μg/L were obtained for Li (λ=670.784nm), Na
(λ=589.592nm), and K (λ=766.490nm). Compared to conventional sample uptake rates
of 1–2mL/min, the 350μL/min used in this study helped to lower the radiation
dose to the ICP-OES operator and produced much less radioactive waste while at
the same time improving LODs. Calibration curves were linear up to 4mg/L with a
correlation coefficient of better than 0.999. Because of its robust and
reproducible performance, no internal standard was required to correct for
potential drifts in sensitivity of the ICP-OES. Three certified water reference
materials (BCR®-617, LGC6177, SRM® 1643a) were employed to assess the accuracy
of the developed ICP-OES procedure, the results of which underpin its
reliability. In addition, Na and K concentrations calculated from emission
intensities measured at two wavelengths confirmed that each dataset is
consistent in itself. A comparison of sector field ICP-MS results of 23 samples
originating from pyrochemical reprocessing with the data obtained applying the
newly developed ICP-OES procedure revealed that the latter provides a reliable,
straightforward and more robust analytical approach to determine Na, K, and Li
in radioactive specimens.
Publication year:
2012 Source:Microchemical Journal, Volume 105 William Maher, Frank
Krikowa, Michael Ellwood, Simon Foster, Rajani Jagtap, George Raber In this
review we present an overview of hyphenated techniques using an ICPMS detector
with an emphasis on extraction techniques for the measurement of metalloids by
high pressure liquid chromatography–inductively plasma mass spectrometry
(HPLC–ICPMS). Five modes of using hyphenated ICPMS systems; HPLC–ICPMS,
HPLC–hydride generation-ICPMS, Cryogenic trapping ICPMS, in-situ Cryogenic
trapping ICPMS and Gas Chromatography–ICPMS are described together with their
application for the measurement of arsenic, selenium, mercury and antimony
species. Two classes of metalloid species are described; “Easy to extract
species,” stable species existing as discrete molecules or relatively weakly
bound to cellular constituents, and Hard to extract species,” unstable species
that dissociate on extraction and species incorporated within cellular
constituents such as proteins. Measurements described include, arsenic species:
arsenobetaine, arsenoribosides, arsenic bound to lipids and phytochelatins and
other minor arsenic species including thioarsenic species. Selenium species:
selenocysteine and selenomethionine, Se-methyl selenomethionine, Se-methyl
selenocysteine, y-glutamyl-Se-methylselenocysteine, dimethylselenide and
dimethyldiselenide. Mercury species: inorganic Hg and methyl Hg. Antimony
species: antimonite and antimonate. Germanium species: inorganic. Extraction
methods are discussed in terms of their extraction efficiencies, stability of
species and artifact formation.
Highlights
► Five modes of using hyphenated ICPMS systems are
described. ► Extraction of species is reviewed in terms of their extraction
efficiencies, stability of species and artifact formation. ► Easy to extract
species are identified as species existing as discrete molecules or weakly bound
to cellular constituents. ► Hard to extract species are identified as species
that dissociate or incorporated within cellular constituents e.g.
proteins.
Publication year:
2012 Source:Microchemical Journal, Volume 105 Uwe Christians, Jacek
Klepacki, Touraj Shokati, Jost Klawitter, Jelena Klawitter Biomarkers, or
more specifically molecular markers, can detect biochemical changes associated
with disease processes and drug effects before histopathological and
pathophysiological changes occur. Multiplexing technologies such as
high-performance liquid chromatography/ mass spectrometry (LC-MS) allow for the
measurement of molecular marker patterns that confer significantly more
information than the measurement of a single parameter alone. The use of
multiplexing assays for drug development, and as diagnostic tools, is attractive
but will require regulatory review and approval and thus requires validation
following regulatory guidance. Multiplexing assays always constitute a
compromise. The number of analytes that can reasonably be included in a mass
spectrometry-based multiplexing assay depend on the physico-chemical properties
of the analytes and their integration into a single assay in terms of
extraction, HPLC separation, ionization conditions and mass spectrometry
detection. Another aspect includes biomedical considerations such as the
differences in physiological concentrations of analytes, the required
concentration range, and how much variability is acceptable before the clinical
utility of a marker is negatively affected. Regulatory considerations include
validation and quality control during sample analysis. Current bioanalytical
regulatory guidelines have mostly been developed for single drug compounds and
are not always adequate for multiplexing molecular marker assays that often
quantify endogenous compounds. Specific guidances for multiplexing assays should
be developed. Even if it is possible to integrate a wide variety and large
number of analytes into a multiplexing assay, it should always be taken into
consideration that a set of shorter, more specialized assays, may offer a more
manageable and efficient alternative.
Publication year:
2012 Source:Microchemical Journal, Volume 105 Petra Krystek This
paper gives a general overview about bio distribution studies which are
especially related to engineered nanoparticles (NPs) made of gold and silver.
The analysis of biological materials from bio distribution studies plays a
significant role in the application of atomic spectrometry to study NPs.
Therefore, special focus is given to the generally applied strategy as well as
the use of the inductively coupled plasma mass spectrometry (ICP-MS) technique
for the determination of the NPs containing metals. An overview of the recent
research applications on gold and silver NPs is also presented. While for gold
NPs a large variety of very different sizes, shape and coating are known, they
also provide many opportunities in imaging, diagnostics, and therapies of
nanomedicine. Hence, their bio kinetics in the body are prerequisites for
specific tailoring of nanomedicinal applications and for a comprehensive risk
assessment. Silver NPs are applied in a lot of consumer products; therefore it
is useful to get a better understanding of their in vivo distribution.
Publication year:
2012 Source:Microchemical Journal, Volume 105 Patricia Grinberg,
Ralph E. Sturgeon, Graeme Gardner The volatile products of photochemical
generation (PVG) of iron from solutions of formic and acetic acids were examined
by GC-MS. Iron pentacarbonyl was the sole analytical species detected in both
cases, as confirmed by comparison of the results with a NIST reference spectrum.
Silylation of the interior surfaces of the quartz tubing comprising the
photochemical reactor essentially eliminated memory effects such that signal
duration was determined simply by the residence time of the sample solution.
Highlights
► The volatile products of PVG of Fe were examined
by GC-MS. ► Iron pentacarbonyl was the specie detected in the presence of formic
and acetic acid. ► Comparison of the results with a NIST reference spectrum. ►
Silylation of the interior surfaces of the quartz tubing eliminated memory
effects.
Publication year:
2012 Source:Microchemical Journal, Volume 105 C. Derrick Quarles,
Benjamin T. Manard, Carolyn Q. Burdette, R. Kenneth Marcus The roles of the
electrode material and geometry on the performance of the liquid
sampling-atmospheric pressure glow discharge (LS-APGD) optical emission
spectroscopy source are described. The LS-APGD source has been interfaced to a
high resolution JY RF-5000 polychromator allowing for simultaneous multiple
element detection. This LS-APGD source operates at currents of 20–60mA and
solution flow rates of 0.1–0.4mLmin−1. A glow discharge is generated
between the surface of the electrolyte test solution exiting a glass capillary
and the end of a metallic counterelectrode. Described here is an evaluation of
how the counterelectrode material identity (copper, nickel, and stainless steel)
and the electrode configuration (geometry) influence the analyte emission
responses for a test solution containing Ag, Cr, Cu, Mg, Ni, and Zn in 1M HNO3.
Studies of the effect of liquid flow rates reveal that 0.3mLmin−1
provides optimal analyte emission responses as it relates to peak intensity,
peak area, and peak widths. Use of nickel as the counterelectrode material
provided the best reproducibility for analyte emission responses with
8.9–13.0%RSDs for 50μL injections of 100μgmL−1 test solutions, while
copper and stainless steel electrodes had %RSDs of 3–5 times higher than the
nickel electrode. The role of the electrode geometries were evaluated
previously-used 180° (co-linear) arrangement as well as for different
configurations with the electrodes mounted at 90° with respect to each other,
with the most intense optical emission responses found for the 180° geometry.
Solution-based limits of detection (LOD) were found to be in the range of
0.44–0.93μgmL−1 for Ag, Cu, Mg, Ni, and Zn using the nickel electrode
at the 180° geometry. Based on the use of 50μL injections, this represents
absolute detection limits of 22–46ng. LODs were approximately an order of
magnitude higher for the copper and stainless steel electrodes.
Highlights
► Key operation parameters of the LS-APGD-OES
microplasma source are studied. ► Electrode powering schemes effect emission and
temporal responses of analytes. ► Ni counterelectrodes produce superior
performance in all aspects of OES analysis. ► Collinear electrodes show better
analytical performance than a 90° arrangement.
Publication year:
2012 Source:Microchemical Journal, Volume 105 John Lewis, Penny
Stokes, Nicola Brereton, Malcolm Baxter, Roy Macarthur As part of a major
survey investigating the levels of total and inorganic arsenic in a range of
fish, shellfish and seaweed, a stability study was undertaken so as to ensure
that the arsenic speciation profile in samples which had been stored for a
number of months was likely to have remained unchanged. The potential for
different sample preparation regimes to impact on arsenic speciation profiles
was also assessed. The data from an initial time-based investigation suggested
that the relative levels of inorganic arsenic did not vary over the 9month
period of the study. However, as it had taken 10days to land, transport and
process the fish material, prior to starting the stability study, a second study
was undertaken, where the death-to-testing time was reduced to 3days. The data
from this second study confirmed that from the first, showing that the
speciation profile did not change, even during the early stages, when poorly
controlled sample handling was potentially at its maximum. Data from the sample
preparation experiment indicated that the preparation format, i.e., “wet” vs.
“freeze-dried,” could influence the relative levels of inorganic arsenic, with
less being measured in the latter format (0.14%±0.08%). Possible explanations
were given, including microbiological activity within the “wet” samples.
However, it was thought most likely to be due to analytical variation
encountered when working at, or below, the methodological LOQ. It is hoped that
this information will assist others regarding issues to be considered when
performing similar studies.
Highlights
► Chemical speciation often dictates the toxicity
of an element. ► Sample storage conditions can affect metal speciation
stability. ► Arsenic species are stable in fish flesh, under different sample
preparation formats. ► Arsenic species are stable in fish flesh, under different
sample storage conditions. ► Results prove data accuracy, obtained from
long-term stored samples, in FSA survey.
Publication year:
2012 Source:Microchemical Journal, Volume 105 Silvano Focardi In
this paper, the presence and amount of mercury and polychlorobiphenyls (PCBs)
were determined in more than 1000 food items collected monthly in the period
2001–2010 in commercial food shops in Siena (Tuscany, Italy), in order to assess
risk to humans due to food consumption. The overall results clearly show a
strong difference in concentration of the two contaminants between foods from
the terrestrial trophic web and those from the marine trophic web. Particular
attention was paid to study the Mediterranean swordfish (Xiphias gladius) and
bluefin tuna (Thunnus thynnus) because anthropic impact on these species is
great due to their topmost position in trophic webs; thus it is very important
to know their health status and evaluate their toxicity for humans. Many samples
of bluefin tuna and swordfish show mercury levels higher than 0.5mg/kg f.w.,
which is the maximum level set by the European Commission (EC, Regulation n.
1881/2006) for most fish species. Taking into account the important nutritional
contribution that fish makes to the diet, it is advisable that women of
childbearing age, pregnant and breastfeeding women as well as young children
select fish from a wide range of species, without giving undue preference to
large predatory fish such as swordfish and tuna. In any case, it is interesting
to note a significant decrease in levels of both mercury and PCBs in bluefin
tuna and swordfish found in the Sienese market over the course of the past ten
years.
Highlights
► The study was carried out on samples of several
food items collected in Siena (Tuscany, Italy). ► We have analyzed mercury and
polychlorobiphenyls (PCBs). ► The results show high levels of these two
contaminants in food from marine origin. ► The results show a decrease in these
two contaminants in food in last ten years. ► Pregnant and breastfeeding women
must select fish from a wide range of species.
Publication year:
2012 Source:Microchemical Journal, Volume 105 Cristina García
Sartal, María del Carmen Barciela-Alonso, Pilar Bermejo-Barrera Seafood,
including edible seaweed, contains high levels of arsenic. The intake of seaweed
is a route to arsenic exposure. Due to the different toxic behaviors among
arsenic species, speciation studies are a matter of vital importance to evaluate
possible health risks for consumers. Most seaweeds are ingested after a heat
treatment and these thermal procedures could lead to a change in arsenic
speciation. In this work an arsenic speciation study of four edible seaweeds
(Kombu, Wakame, Nori and Sea Lettuce) after cooking has been performed by
anion-exchange HPLC connected to an ICP-MS for arsenical detection. Speciation
studies were also carried out in the cooking waters of those samples. Powdered
cooked seaweed was subjected to an in-vitro digestion procedure by using
Piperazine-NN-bis (2-ethane-sulfonic acid) disodium (PIPES), as a buffer
solution at a pH of 7.0 and dialysis membranes of 10kDa molecular weight cut off
(MWCO). Dialyzable fractions were analyzed to identify the arsenic species that
become bioavailable for human body functions. Total arsenic concentrations were
found between 5.3 and 79.1μgg−1, 3.6–36.7μgg−1 and
1.8–54.3μgg−1 for raw and cooked seaweed, and cooking water,
respectively. Total arsenic bioavailability percentages were 20%, 29%, 18% and
11% for cooked Kombu, Nori, Wakame and Sea lettuce, respectively. Results
suggest that the heat treatment and the acidic environment and enzymes used in
the in-vitro gastrointestinal digestion are not sufficient to produce a change
in the arsenic species of the four seaweeds studied. Arsenic species are
comparable in each seaweed before and after being cooked, their cooking water
and dialysate. Arsenosugars were the main arsenic species found. As(III) species
and arsenobetaine (AB) were only found in the Sea Lettuce sample. Glycerol sugar
and sulfonate sugar were the most bioavailable species for cooked Kombu and
Wakame. Phosphate sugar showed to be in highest proportion in the dialyzable
fraction of Nori. AB and glycerol sugar became more bioavailable in the Sea
Lettuce sample.
Highlights
► Qualitative arsenic speciation study in seaweeds
► Characterization of arsenic species in edible seaweeds after cooking ► Arsenic
speciation study in dialysates of cooked seaweeds
Publication year:
2012 Source:Microchemical Journal, Volume 105 Iva Juranović
Cindrić, Michaela Zeiner, Martina Krpetić, Gerhard Stingeder Inductively
coupled plasma atomic emission spectrometry (ICP-AES) was used for the
determination of minor and major elements present in Cornelian cherry (Cornus
mas L.), as this fruit and its preservatives may be considered as important
nutritional supplements. Prior to ICP-AES measurement, the samples were digested
in a microwave assisted digestion system. The ICP-AES method was validated and
optimized for the determination of selected elements in Cornelian cherry. The
accuracy of the method as estimated through by spiking experiments was
satisfactory, the recoveries obtained after microwave digestions in whole fruit
(A), mesocarp (B) seed (C), and juice ranged from 84–123%, 74–115% 82–124%, and
from 83–116% respectively. For microwave assisted digested Cornelian cherry
samples of whole fruit (A), mesocarp (B) and seeds (C) the following limits of
detection were obtained <2ng/g for Al, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb,
Sr, Zn, Mg, and K, moderate 2–10ng/g for B, and Ca. The highest LODs were
obtained only for Al in mesocarp (B) and seeds (C) compared with whole fruit
(A). For microwave assisted digested Cornelian cherry juice the limits of
detection were in the range 0.04–0.108μg/L. The precision of the method was
evaluated using the standard deviation, RSD, of repeated determinations of the
analytes and for all elements RSD ranged from 0.5 to 7% except for Na 12%. The
intermediate precision (< 4.8%), the day-to-day reproducibility (< 6.8%),
and the overall uncertainty of measurement (approx. 4–10%) for all elements
analyzed demonstrated the good applicability of the chosen microwave assisted
digestion procedure. Regarding potentially toxic elements, Cu and Pb are below
4μg/g in the whole berry, Cr and Cd were not even detected.The order of
magnitude of the concentrations for the elements found in whole fruit (whole
fruit, A) and seed (C) is found to be similar for most of the elements of
interest, namely in μg/g: 2.52 and 6.0 B, 2074.4 and 3971.8 Ca, 2.4 and 2.4 Cu,
7.8 and 4.1 Fe, 4019 and 3288 K, 288 and 237 Mg, 1.65 and 3.1 Mn, 22.9 and 41
Na, 9.0 and 6.9 Ni, 2.9 and 3.3 Pb, 6.9 and 12.5 Sr, respectively. In Cornelian
cherry juice the content of Al, Ba, Cd, Cr, Cu, Mn, Pb, and Sr were below the
limits of detection (0.06, 0.07, 0.07, 0.006, 0.01, 0.042, 0.056, 0.04 and
0.009μg/L, respectively). The content of minor elements was 0.135 Fe, 0.163 Ni,
0.828 Zn and 1.47mg/L B. The concentrations of major elements were 11.3 Na, 51.7
Ca, 94.3Mg and 1326mg/LK.
Highlights
► Popularization of Cornelian cherry and the
potential of European cultivars as a new promising fruit species. ► The
elemental content of berries influences the quality of fruit, including
organoleptic characteristics and stability. ► Metal concentrations were
determined using ICP-AES. ► The knowledge of the mineral contents of berries is
important from the toxicological point of view. ► This study is important
confirms the importance of Cornelian cherry as nutritional
supplement.
Publication year:
2012 Source:Microchemical Journal, Volume 105 Agustín Londonio,
Fabián Fujiwara, Raúl Jiménez Rebagliati, Darío Gómez, Patricia Smichowski An
investigation was carried out to explore the effect of citric, hydrochloric,
oxalic and tartaric acids on mercury vapor generation in a flow injection system
in conjunction with atomic absorption spectrometry detection (CV-AAS) for its
determination in road dust samples. Samples were collected in Buenos Aires
(Argentina) during two months at 15 sites grouped in five zones with different
urban characteristics and traffic profile. They were sieved in four fractions
(with the following particle diameter (d): A: d <37μm, B: 37< d <50μm,
C: 50< d <75μm, and D: 75< d <100μm) before Hg determination. The
operating conditions (chemical and physical parameters) and the type and
concentration of the acids studied (citric, hydrochloric, oxalic and tartaric)
were assessed for the efficient generation of Hg. The interfering effect of
metals and metalloids, present as minor and major concentrations in road dust,
on Hg signal were evaluated using the four acids. Hydrochloric acid resulted to
be the most convenient reaction medium in terms of sensitivity but a suitable
control of interferences was not reached. For a complex matrix such as road
dust, the best control of interferences was achieved when oxalic acid was
tested, even when lower Hg signal was obtained in comparison with HCl. The
detection limit (3σ criterion) turned out to be 0.3ngg−1. For
checking accuracy, two certified reference materials were analyzed and results
were in good agreement with certified values. Mercury concentrations in road
dust ranged between 0.1μgg−1 and 4.6μgg−1 and the mean
concentration value resulted to be 1.09μgg−1. In the four fractions,
Hg concentrations (μgg−1) varied as follows: Fraction A
(<0.0003–3.51); Fraction B (0.49–4.63); Fraction C (0.20–1.36) and Fraction D
(0.16–1.88). The procedure is simple, rapid and robust.
Highlights
► We determined by the first time Hg on road dust
samples collected in Buenos Aires. ► We compared four acid media for Hg vapor
generation. ► The effect of each acid media on the control of interferences was
assessed. ► The use of organic acids for Hg vapor generation is the most correct
procedure from the environmental point of view. ► This work reports by the first
time concentrations of Hg in Buenos Aires road dust as well as information on
its origin.
Publication year:
2012 Source:Microchemical Journal, Volume 105 Zoltán Sávoly, Péter
Nagy, Károly Havancsák, Gyula Záray The chemical characterization of
individual free-living nematodes is a challenge due to their small size and
correspondingly, their low dry mass (1–3μg). The concentrations of minor (S, P,
Ca, K) and trace elements (Fe, Zn, Cu, Ni, and Mn) of individual specimens
(Xiphinema Vuittenezi) were determined by total reflection X-ray fluorescence
(TXRF) spectrometry following a two step sample preparation procedure. The mean
concentrations of minor and trace elements changed in the range of 1–4 and
0.01–0.4ng/μg, respectively. The relative standard deviation varied between 9.4
and 25.3% which was influenced not only by the analytical procedure but also by
the biological deviations among the eleven investigated specimens. The stress
effect caused by CuSO4 treatment resulted in significant change in the nematodes
only in their Zn content. In the lack of certified reference material, the TXRF
method was checked by inductively coupled plasma mass spectrometry (ICP-MS)
analyzing solutions of 100 digested nematodes. The carbon and nitrogen content
of nematodes was also measured by total C/N analyzer and their ratio amounted to
4.78±0.31 which is lower than the values published for the bacterial or fungal
feeding ones. The way of copper uptake was investigated by scanning electron
microscopy (SEM). Nematode treated with copper-nitrate was pecked out at the
mid-body using focused ion beam (FIB) technique. In order to preserve the
cross-section to be investigated, platinum coating was applied prior to the FIB
operation. Energy dispersive X-ray analysis was performed along the
cross-section measuring the distribution of platinum, sulfur and copper. It has
been found that the sulfur and copper distributions were fairly similar
following the copper treatment, and these elements had the highest concentration
in the cuticle.
Highlights
► Elemental analysis of individual plant parasitic
nematodes by TXRF spectrometry. ► Determination of cross sectional distribution
of elements by focused ion beam-SEM. ► Bulk analysis of 100 nematodes by ICP-MS
following a microwave-assisted digestion.
Publication year:
2012 Source:Microchemical Journal, Volume 105 Barbara Leśniewska,
Beata Godlewska-Żyłkiewicz, Agnieszka Z. Wilczewska A new type of
Cr(III)-imprinted polymer was prepared from Cr(III)–pyrrolidinedithiocarbamate
complex, acrylamide functional monomer and ethylene glycol methacrylate
cross-linking agent. The polymer was employed as a selective solid phase
extraction material for separation of trace amounts of Cr(III) ions under
dynamic conditions. The effects of the conditioning of imprinted polymer,
conditions of Cr(III) retention and elution were studied. It was found that
Cr(III) ions can be retained on tested sorbent with high efficiency and
repeatability (87%, RSD=3.2%) from a solution of pH 3.50–4.75. The quantitative
elution of analyte was obtained with 0.2molL−1 nitric acid solution.
The retention of Cr(VI) ions on the polymer in the studied pH range (1.0–7.0)
was at the level of 10–15%. The selectivity of prepared sorbent towards Cr(III)
ions was good in the presence of Cu(II) and Ni(II) ions and worse in the
presence of Fe(III) ions at a concentration higher than 0.5μgmL−1.
The detection limit for Cr(III) obtained by electrothermal atomic absorption
spectrometry (ETAAS) after preconcentration of 40mL of sample on the polymer was
0.018ngmL−1. The developed separation method was successfully applied
to the ETAAS determination of trace amounts of Cr(III) in tap and river water
and municipal sewage.
Highlights
► New type of imprinted polymer was prepared for
separation and enrichment of Cr(III) ions. ► The selectivity is characterized
with retention values of 87% and 6–15% for Cr(III) and Cr(VI) ions,
respectively. ► Applications to speciation analysis and for determination of
Cr(III) ions in surface water and sewage samples are described.
