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World Congress on Biosensors 2014
Biosensors 2014
Monday 26 November 2012
Just Published: Analytica Chimica Acta
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:
Publication year:
2012 Source:Analytica Chimica Acta, Volume 756 Liang Wu, Yan Yang,
Hejing Zhang, Gangbing Zhu, Xiaohua Zhang, Jinhua Chen By using biobarcode
nanoparticles, we have successfully constructed a DNA-based biosensor for
amplified electrochemical detection of hydroxyl radical (OH). Thiolated DNA1
(SH-DNA1) was firstly immobilized on the planar gold (Au) electrode. OH
generated from Fenton reaction could induce serious oxidative damage of the DNA
layer adsorbed on the electrode surface, which was monitored by an intercalating
probe, methylene blue (MB). In order to enhance the sensitivity of the
biosensor, DNA2-functionalized Au nanoparticles (DNA2-AuNPs) were used to
amplify the response signal. The developed DNA-based biosensor could detect OH
quantitatively with wide linear range up to 10mM and low detection limit of 3μM,
and exhibited satisfactory selectivity. On the other hand, this electrochemical
biosensor could have potential application in the evaluation of antioxidant
capacity.
Graphical abstract
Graphical abstract Highlights
. ►
A DNA-based biosensor for amplified electrochemical detection of OH was
developed. ► The sensor shows good analytical performance for sensitive
detection of OH. ► The biosensor has potential application in the evaluation of
antioxidant capacity.
Publication year:
2012 Source:Analytica Chimica Acta, Volume 756 Wen Zhang, Yaqin
Chai, Ruo Yuan, Shihong Chen, Jing Han, Dehua Yuan In the present work, a
tube-like structure of graphene hybrid as modifier to fabricate electrode for
simultaneous detection of ascorbic acid (AA), dopamine (DA), uric acid (UA) and
tryptophan (Trp) was reported. The hybrid was synthesized by a simple method
based on graphene sheets (GS) and 3,4,9,10-perylenetetracarboxylic acid (PTCA)
via π–π stacking interaction under ultrasonic condition. The combination of GS
and PTCA could effectively improve the dispersion of GS, owing to PTCA with the
carboxylic-functionalized interface. Comparing with pure GS or PTCA modified
electrode, GS–PTCA displayed high catalytic activity and selectivity toward the
oxidation of AA, DA, UA, and Trp. Moreover, cyclic voltammetry, different pulse
voltammetry and scanning electron microscopy were employed to characterize the
sensors. The experiment results showed that the linear response range for
simultaneous detection of AA, DA, UA, and Trp were 20–420μM, 0.40–374μM, 4–544μM
and 0.40–138μM, respectively, and the detection limits were 5.60μM, 0.13μM,
0.92μM and 0.06μM (S/N =3). Importantly, the proposed method offers promise for
simple, rapid, selective and cost-effective analysis of small biomolecules.
Graphical abstract
Graphical abstract Highlights
A tube-like structure of
graphene hybrid (GS–PTCA) was synthesized via π–π stacking interaction, and was
used as modifier to fabricate electrode for simultaneous detection of ascorbic
acid (AA), dopamine (DA), uric acid (UA) and tryptophan (Trp). SEM images of GS,
PTCA and GS–PTCA were presented. Under the synergistic effects between GS and
PTCA, the modified electrode displayed high catalytic activity and selectivity
toward the oxidation of AA, DA, UA, and Trp. ► A
simple strategy for simultaneous detection of AA, DA, UA and Trp has been
constructed. ► The tube-like structure of graphene hybrid (GS–PTCA) was
synthesized. ► The GS–PTCA provided a selective interface for discrimination of
AA, DA, UA and Trp.
Publication year:
2012 Source:Analytica Chimica Acta, Volume 756 Elham Tahmasebi,
Yadollah Yamini A novel sorbent for magnetic solid-phase extraction by
self-assembling of organosulfur compound,
(bis-(2,4,4-trimethylpentyl)-dithiophosphinic acid), onto the silver-coated
Fe3O4 nanoparticles was introduced. Due to the formation of covalent bond of
SAg, the new coating on the silver surface was very stable and showed high
thermal stability (up to 320°C). The size, morphology, composition, and
properties of the prepared nanoparticles have also been characterized and
determined using scanning electron microscopy (SEM), energy-dispersive X-ray
analyzer (EDX), dynamic light scattering (DLS), Fourier transform-infrared
(FT-IR) spectroscopy, and thermal gravimetric analysis (TGA). Extraction
efficiency of the new sorbent was investigated by extraction of five polycyclic
aromatic hydrocarbons (PAHs) as model compounds. The optimum extraction
conditions for PAHs were obtained as of extraction time, 20min; 50mg sorbent
from 100mL of the sample solution, and elution with 100μL of 1-propanol under
fierce vortex for 2min. Under the optimal conditions, the calibration curves
were obtained in the range of 0.05–100μgL−1 (R 2
>0.9980) and the LODs (S/N=3) were obtained in the range of
0.02–0.10μgL−1. Relative standard deviations (RSDs) for intra- and
inter-day precision were 2.6–4.2% and 3.6–8.3%, respectively. In addition,
feasibility of the method was demonstrated with extraction and determination of
PAHs from some real samples containing tap water, hookah water as well as soil
samples with relative recovery of 82.4–109.0% and RSDs of 3.5–11.6%.
Graphical abstract
Graphical abstract Highlights
Self assembling of
bis-(2,4,4-trimethylpentyl)-dithiophosphinic acid on Fe3O4@Ag core@shell
nanoparticles and application of it for solid phase extraction of PAHs. ► A novel sorbent for magnetic solid-phase extraction of
PAHs was introduced. ► Silver was coated on Fe3O4 nanoparticles (MNPs) by
reduction of AgNO3 with NaBH4. ► Bis-(2,4,4-trimethylpentyl)-dithiophosphinic
acid self-assembled on silver coated MNPs. ► Size, morphology, composition and
properties of the nanoparticles were characterized. ► Extraction efficiency of
the sorbent was investigated by extraction of five PAHs.
Publication year:
2012 Source:Analytica Chimica Acta, Volume 756 Xavier de la Torre,
Cristiana Colamonici, Davide Curcio, Francesco Molaioni, Francesco Botrè The
confirmation by GC/C/IRMS of the exogenous origin of pseudo-endogenous steroids
from human urine samples requires extracts of adequate purity. A strategy based
on HPLC sample purification prior to the GC/C/IRMS analysis of human urinary
endogenous androgens (i.e. testosterone, androsterone and/or androstenediols),
is presented. A method without any additional derivatization step is proposed,
allowing to simplify the urine pretreatment procedure, leading to extracts free
of interferences permitting precise and accurate IRMS analysis, without the need
of correcting the measured delta values for the contribution of the derivatizing
agent. The HPLC extracts were adequately combined to both reduce the number of
GC/C/IRMS runs and to have appropriate endogenous reference compounds (ERC; i.e.
pregnanediol, 11-keto-etiocholanolone) on each GC–IRMS run. The purity of the
extracts was assessed by their parallel analysis by gas chromatography coupled
to mass spectrometry, with GC conditions identical to those of the GC/C/IRMS
assay. The method has been validated according to ISO17025 requirements (within
assay precision below 0.3‰ 13C delta units and between assay
precision below 0.6‰ 13C delta units for most of the compounds
investigated) fulfilling the World Anti-Doping Agency requirements.
Graphical abstract
Graphical abstract Highlights
►
Overall approach for urine samples purification by HPLC for subsequent GC/C/IRMS
analysis in doping control. ► Detection of pseudo-endogenous androgenic steroids
(i.e. testosterone, androstenedione) misuse in sports. ► Routine analysis of
steroids by GC/C/IRMS in sports drug testing.
Publication year:
2012 Source:Analytica Chimica Acta, Volume 756 Marcos Bouza,
Beatriz Fernández, Cristina González-Gago, Nerea Bordel, Rosario Pereiro,
Alfredo Sanz-Medel Radiofrequency (RF) millisecond pulsed glow discharge
(PGD) coupled to time-of-flight mass spectrometry (TOFMS) was investigated for
direct elemental analysis of glass samples. Aiming at achieving highest
elemental sensitivity, appropriate discrimination from polyatomics, and good
crater shapes on glasses, a new Grimm-type GD chamber (termed from now “UNIOVI
GD”, designed and constructed in our laboratory) was coupled to TOFMS, and the
results compared with those obtained with the former GD design (here denominated
as “GD.1”) of the initial RF-PGD-TOFMS prototype. The critical differences
distinguishing the two GDs under scrutiny are the GD chamber thickness (15.5mm
for the GD.1 and 7mm for the UNIOVI GD) and the “flow tube” which is inserted in
the GD.1 and inexistent in UNIOVI GD. A pulse period of 4ms and a duty cycle of
50% were selected for the PGD studies. In order to characterizing the UNIOVI GD,
the effect of RF-PGD experimental conditions (pressure and power) on signal
shapes along the pulse was first investigated. Then, the analytical performance
achieved was compared with results obtained using the GD.1 chamber. Results show
that the UNIOVI GD source induced less thermal stress on the glass specimens.
Consequently higher GD power can be applied to the UNIOVI GD (up to at least
130W), as compared to the GD.1 (maximum of 60W), without glass sample breakdown.
Also, better crater shapes on samples were obtained using the UNIOVI GD.
Moreover, the detection limits attained with the UNIOVI GD (in the range of
μgg−1) were in most cases about one order of magnitude better for the
analytes investigated (B, Na, Al, Si, Mn, Ni, Co, Cu, Zn, As, Sr, Ag, In, Sn,
Sb, Ba, Pb and Bi), than those observed using the GD.1.
Graphical abstract
Graphical abstract Highlights
► A
new GD chamber coupled to TOFMS was investigated for direct glass analysis. ►
The effect of GD experimental conditions on signal shapes was investigated. ►
The proposed GD induced less thermal stress on samples than previous GD designs.
► Better detection limits were found compared to those obtained with previous
GDs.
Publication year:
2012 Source:Analytica Chimica Acta, Volume 756 S. De Baere, A.
Osselaere, M. Devreese, L. Vanhaecke, P. De Backer, S. Croubels A sensitive
and specific method for the quantitative determination of zearalenone (ZEN) and
its major metabolites (α-zearalenol (α-ZEL), β-zearalenol (β-ZEL), α-zearalanol
(α-ZAL), β-zearalanol (β-ZAL) and zearalanone (ZAN)) in animal plasma using
liquid chromatography combined with heated electrospray ionization (h-ESI)
tandem mass spectrometry (LC–MS/MS) and high-resolution Orbitrap®
mass spectrometry ((U)HPLC–HR–MS) is presented. The sample preparation was
straightforward, and consisted of a deproteinization step using acetonitrile.
Chromatography was performed on a Hypersil Gold column (50mm×2.1mm i.d., dp:
1.9μm, run-time: 10min) using 0.01% acetic acid in water (A) and acetonitrile
(B) as mobile phases. Both mass spectrometers were operated in the negative
h-ESI mode. The method was in-house validated for all analytes: matrix-matched
calibration graphs were prepared and good linearity (r ≥0.99) was achieved over
the concentration range tested (0.2–200ngmL−1). Limits of
quantification (LOQ) in plasma were between 0.2 and 5ngmL−1 for all
compounds. Limits of detection in plasma ranged from 0.004 to
0.070ngmL−1. The results for the within-day and between-day
precision, expressed as relative standard deviation (RSD), fell within the
maximal RSD values (within-day precision: RSDmax =2(1–0.5logConc) x
2/3; between-day precision: RSDmax =2(1–0.5logConc)). The accuracy
fell within −50% to +20% (concentrations <1ngmL−1), −30% to +10%
(concentrations between 1 and 10ngmL−1) or −20% to +10%
(concentrations >10ngmL−1) of the theoretical concentration. The
method has been successfully used for the quantitative determination of ZEN in
plasma samples from broiler chickens and pigs. α-ZEL and β-ZEL were the only
metabolites that could be detected, but the concentrations were around the LOQ
levels. The intact ZEN-glucuronide conjugate could be detected using the
(U)HPLC–HR–MS instrument. A good correlation (r 2 =0.9979) was
observed between the results for ZEN obtained with the LC–MS/MS and
(U)HPLC–HR–MS instruments. The results prove the usefulness of the developed
method for application in the field of toxicokinetic analysis and for exposure
assessment of mycotoxins.
Graphical abstract
Graphical abstract Highlights
►
Qualitative+quantitative analyses of zearalenone with LC–MS/MS and
(U)HPLC–HR–MS. ► Development of a generic, rapid and cheap sample preparation
procedure. ► Chromatograhy: baseline separation of metabolites with same
precursor ion, run-time: 10min. ► Method validation: linearity, accuracy,
precision, LOQ, LOD, specificity, recovery and matrix effects. ► Investigation
of toxicokinetics of zearalenone in chickens.
Publication year:
2012 Source:Analytica Chimica Acta, Volume 756 Davinson Pezo, Mauro
Fedeli, Osvaldo Bosetti, Cristina Nerín Toxic primary aromatic amines (PAAs)
are reaction products from residual isocyanates in polyurethane adhesives. The
maximum migration level of the total sum of PAAs is 10ngg−1 of food.
This paper reports on a method for quantification of 18 PAAs by UHPLC–MS/MS that
was optimised and applied to a series of industrial laminates prepared from
polyurethane adhesives. Non-intentionally added substances (NIAS), impurities
and other migrants were identified by Q-TOF/MSE. A comparison of the
quantitative values obtained by the colorimetric method using NEDA and by
UHPLC–MS/MS confirmed that the first method can overestimate the quantification
of PAAs. This could be attributed to the impurities and other NIAS present in
the plastic laminate. Values of R 2 in the analytical characteristics
of UHPLC–MS/MS were obtained, the best value being 0.9964 and the most
unfavourable 0.7626. The detection limit (LOD) and the quantification limit
(LOQ) were 2pgg−1 and 7pgg−1, respectively. The stability
of the PAAs over time in the acidic simulant in contact with the plastic
laminate is also reported.
Graphical abstract
Graphical abstract Highlights
► 18
primary aromatic amines from adhesives in multilayer plastics are analysed by
UPLC–LC–TQ. ► Non intentionally added substances are identified in the
multilayer materials by UPLC–Q-TOF–MS. ► Quantitative values of PAAs are
compared to those obtained by colorimetric method using NEDA. ► Overestimation
of NEDA procedure is demonstrated. ► Pattern recognition of the impurities and
NIAS from adhesives in the multilayers are achieved.
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