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World Congress on Biosensors 2014
Biosensors 2014
Friday, 29 June 2012
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:Talanta Georgi Stoev, Yue Xuan, Milena Peycheva,
Michaela Scigelova Applications of high resolution mass spectrometry (HRMS)
in food safety and residue analysis have increased remarkably over the last few
years. The high resolution detection of ions reportedly enhances the assay
selectivity but quantitative assessment of HRMS contribution to the assay
selectivity has not yet been undertaken. We devised a method to assess the
impact of instrument resolution on the probability that a spectral assignment to
a given compound was made in error. The method allows for evaluating the quality
of a spectral assignment based on resolution and the number of fragmentation
stages. It thus provides a firm basis for comparing analytical methods performed
on very different mass spectrometric instrumental platforms as well as in the
context of the current regulatory framework.
Graphical abstract
Graphical abstract Highlights
► High
mass resolution impacts positively on the confidence of confirmation. ► Method
quantifies the contribution of the resolution to assay selectivity. ► Method
allows evaluation of regulatory framework identification
criteria
Publication year:
2012 Source:Talanta Isabela Maia Toaldo, Gabriel Zandonadi Gamba,
Lidia Almeida Picinin, Gabriel Rubensam, Rodrigo Hoff, Marilde
Bordignon-Luiz A simplified procedure for simultaneous quantification of
ceftiofur (CEF), fluoroquinolone (FQ) and sulfonamide (SA) antibacterials in
bovine milk was developed. The reverse-phase liquid chromatography (RP-LC)
multiclass method for analysis of eleven distinct compounds, from three
antibacterial classes, was validated in line with Commission Decision
2002/657/EC. Confirmation of the analytes identities was performed by
electrospray mass spectrometry detection. The analytes were extracted from milk
matrix by liquid-liquid extraction with acidified ultrapure water and directly
analyzed in the chromatograph. The SA compounds were pre-column derivatized with
fluorescamine for fluorescence detection. The method provided good results
regarding the analytical parameters of linearity, selectivity, sensitivity,
precision, recovery, decision limit (CCα), detection capability (CCβ), limit of
detection (LOD), limit of quantification (LOQ), stability and robustness.
Analytes were extracted by liquid-liquid extraction in the fortified matrix and
the compounds identity was confirmed by their precursor ion and fragments
through tandem mass spectrometry analysis. Additionally, milk samples from two
state capitals in the South Region of Brazil were analyzed by both the
quantitative and confirmatory methods. The validation process showed correlation
coefficients (r 2 ) greater than 0.98 for all the analytes, with
recovery rates up to 98% for all the studied drugs. LOD and LOQ limits ranged
from 8.0 to 20.0ngmL−1 and 10.0 to 32.0ngmL−1,
demonstrating good specificity of the method. The intra-day and inter-day
precisions for all the analytes were below or equal to 7.40 and 10.13,
respectively. The studied antibacterials were not detected in milk samples. The
developed method represents an efficient alternative for multi-residue analysis
in milk, being suitable and especially viable for monitoring in developing
countries.
Highlights
► Sulfonamides, fluoroquinolones and ceftiofur were
determined in milk. ► Acidified water was efficient for extraction without
further clean up procedure. ► Validation results showed great performance for
the LC method. ► Analyzed samples from Brazil showed no detection.► A feasible
alternative to monitor residues in milk was developed.
Publication year:
2012 Source:Talanta Alzira Yamasaki, João A.B.P. Oliveira, Armando
C. Duarte, M.Teresa S.R. Gomes Copper and lead in wine were quantified by
anodic stripping voltammetry (ASV), performed onto the gold electrode of a
piezoelectric quartz crystal. Both current or mass changes could be used as
analytical signals, without a statistical difference in the results (α=0.05).
However, the plot of mass vs. potential provided an in depth understanding of
the electrochemical processes and allowed studying adsorption phenomena. Copper
interaction with fructose is an example of a process which was not possible to
ignore by observing the mass change on the gold electrode of the piezoelectric
quartz crystal.
Publication year:
2012 Source:Talanta Phimpha Soisungnoen, Rodjana Burakham, Supalax
Srijaranai A rapid and sensitive method using two preconcentration
techniques, dispersive liquid-liquid microextraction (DLLME) followed by
reversed electrode polarity stacking mode (REPSM) was developed for the analysis
of five organophosphorus pesticides (OPPs) by micellar electrokinetic
chromatography (MEKC). Parameters that affect the efficiency of the extraction
in DLLME and preconcentration by REPSM, such as the kind and volume of the
extraction and disperser solvents, salt addition, sample matrix and injection
time were investigated and optimized. Under the optimum conditions, the
enrichment factors were obtained in the range from 477 to 635. The linearity of
the method for parathion, azinphos and fenitrithion was in the range of
20–1000ngmL−1, and for malathion and diazinon in the range of
50–1000ngmL−1, with correlation coefficients (r 2) ranging
from 0.9931 to 0.9992. The limits of detecton (LODs) at a signal-to-noice ratio
of 3 ranged from 3 to 15ngmL−1. The relative recoveries of five OPPs
from water samples at spiking levels of 20 and 200ngmL−1 for
parathion, azinphos and fenitrithion, and 50 and 500ngmL−1 for
malathion and diazinon, were 69.5-103%. The proposed method provided high
enrichment factors, good precision and accuracy with a short analysis time.
Publication year:
2012 Source:Talanta Zdeňka Jarolímová, Přemysl Lubal, Viktor
Kanický An analytical method for the determination of the composition of
renal stones by capillary isotachophoresis with conductometric detection was
developed. Using different leading/terminating electrolyte systems, the
qualitative and quantitative analysis of organic compounds (urate, xanthate,
oxalate) and inorganic ions (phosphate, Ca2+, Mg2+,
Na+,, NH4 +) species commonly present in mixed renal
stones in three separate steps can be carried out with limits of detection about
10μmol/L. The developed method was validated by the analysis of real samples and
can be used for urinary calculi classification. In addition, it was verified
that this method can also be employed for the determination of the above
mentioned analytes in some other samples (bones, teeth) concerning apatite
biominerals (fluoro-, carbonate-, chloro-apatite).
Highlights
► Cationic and anionic analysis by capillary
isotachophoresis with conductivity detection. ► The robust and fast method was
developed for analysis of biominerals. ► Application for
qualitative/quantitative analysis of uric stones, bones and
teeth.
Publication year:
2012 Source:Talanta Shijuan Zhang, Jinmao You, Guoying Zhou, Chunli
Li, Yourui Suo A new labeling reagent for fatty acids, 1-(9H-carbazol-9-yl)
propan-2-yl-methanesulfonate (CPMS), has been synthesized and successfully
applied to the HPLC determination of fatty acids in traditional Chinese herb
Notopterygium forbesii Boiss. The reaction of CPMS with fatty acids could
proceed easily and quickly in the presence of K2CO3 catalyst within 30min. The
derivatives exhibit excellent fluorescence property with excitation and emission
wavelengths of 293nm and 360nm, respectively. The 34 derivatives of fatty acids
were separated on a BDS C8 reversed-phase column with gradient elution. Good
linear correlations were observed for all fatty acids with correlation
coefficients of >0.996. The detection limits at a signal-to-noise ratio of 3
were in the range of 0.032–0.312μgg–1. Free fatty acids in the roots,
stem, leaves and petioles of Notopterygium forbesii Boiss from different places
was analyzed by the developed method. This is the first time that the fatty
acids composition of Notopterygium forbesii Boiss has been reported. This method
also shows powerful potential for the trace analysis of fatty acids or other
carboxylic acids from complex samples.
Highlights
► A new labeling reagent for fatty acids has been
synthesized. ► Fatty acids composition of Notopterygium forbesii Boiss was
reported for the first time. ► Sensitivity was much higher than the often used
GC methods.
Publication year:
2012 Source:Talanta K. Volkan Özdokur, Levent Pelit, Hasan Ertaş,
Suna Timur, F. Nil Ertaş Present paper describes the results of a novel
method which combines the Headspace (HS) preconcentration of the analyte on the
electrode prior to the voltammetric analysis. Thereafter, the method was called
HS-Voltammetry. The performance of the method was tested upon using an
electroactive and volatile molecule phenol molecule which gives an oxidation
peak at conventional electrodes. In this study, a glassy carbon electrode was
modified with polypyrrole by electropolymerization and then, the electrode was
placed over the solution in a sealed vial heated gently on a hotplate with a
stirrer for phenol determination. By controlling the thickness of polymeric
coating and optimizing preconcentration parameters such as vial pH and
temperature, stirring rate and exposure time, a very consistent (5.2% at
5.0×10−7 M) fraction of the analyte can be extracted during a
predetermined time. The oxidation peak current at 0.8V depended linearly on the
phenol concentration over a wide range (3 orders of magnitude). The detection
limit was estimated as 7.0×10−8 M at 60°C (S/N=3) which is well below
the limit set by the European Community for phenols in wastewaters (ca.
5×10−6 M). The effect of other phenolic compounds was also examined
and it was shown that head space preconcentration eliminated the interference of
nonvolatile phenolic acids studied. For volatile phenolic compounds, the
selectivity can be maintained in cases when isolated peaks are obtained for each
component. The proposed method has been applied successfully for the
determination of phenol in artificial wastewater and recovery percentage was
calculated as 93%.
Highlight
► Voltammetry was combined with the advantageous of
headspace sampling. ► Detection limit for phenol was improved with HS
accumulation. ► The interference of non-volatile components was eliminated by HS
sampling. ► Phenol and 2,4-dichlorophenol can be determined simultaneously by
this means
Publication year:
2012 Source:Talanta Vo Thanh Phuong Nguyen, Virginie Piersoel,
Tarik El Mahi A sensitive and specific ion-pair reversed-phase high
performance liquid chromatography (HPLC) method for urinary iodine analysis is
described. This method is based on pulsed amperometric detection (PAD) using a
silver working electrode (HPLC-PAD), which improves peak shape, electrode
stability as well as linearity and reproducibility. A two-step extraction
process consisting of solid phase extraction (SPE) and liquid-liquid extraction
with dichloromethane was added in order to improve sample purification which is
essential with the use of PAD. Treated samples were eluted on a C18 column,
using a phosphate buffer containing ion-pairing reagent tetrabutylammonium and
5% MeOH. The calibration standard curves were linear up to 500µg/L and
within-run and between–run coefficients of variation (CVs) were <6% with the
quantification limit fixed at 6µg/L. Accuracy, expressed as recovery, ranged
from 94 to 104%. Comparison with the Technicon AutoAnalyzer acid digestion (AA)
method resulted in a high correlation (r=0.9916). Due to a low quantification
limit and high sample throughput, the proposed technique appears suitable for
both epidemiological and clinical follow-up studies.
Highlights
► We developed a HPLC-PAD method for determining
iodide concentration in urine. ► Pulsed amperometric detection improves peak
shape and electrode stability. ► Two extraction steps for sample purification
are necessary. ► This method is sensitive, selective, precise and accurate. ►
The method is effective for urinary iodine determination.
Publication year:
2012 Source:Talanta Yi Li, Liu Deng, Chunyan Deng, Zhou Nie,
Minghui Yang, Shihui Si A novel electrochemical aptasensor involving quantum
dots-coated silica nanospheres (QDs/Si) and the screen-printed gold electrodes
(SPGE) was developed for the detection of thrombin. The screen-printed electrode
with several advantages including low cost, versatility, miniaturization, and
mechanical regeneration after each measurement cycle were employed. On the other
hand, the gold nanoparticles (AuNPs) were electrodeposited on the surface of
SPGE to obtain the AuNPs/SPGE. And this sandwich format
(Apt/thrombin/Apt−QDs/Si) was fixed on the AuNPs/SPGE to fabricate the
electrochemical aptasensor. The bound CdTe QDs were dissolved in an
acid-dissolution step and were detected by electrochemical stripping analysis.
The proposed aptasensor has excellent performance such as high sensitivity, good
selectivity and analytical application in real samples. The combination of
nanoparticles with the screen-printed electrode is favorable for amplifying
electrochemical signals, and useful for large-scale fabrication of the
electrochemical aptasensors, which would lay a potential foundation for the
development of the electrochemical aptasensor.
Highlights
► We fabricated the electrochemical aptasensor with
simplicity and high sensitivity. ► Gold nanoparticles were electrodeposited onto
the screen-printed electrode. ► The bound QDs were dissolved in an
acid-dissolution step and were detected. ► Nanoparticles may be favorable for
amplifying electrochemical signals. ► The screen-printed electrode was useful
for the large fabrication of the aptasensor.
Publication year:
2012 Source:Talanta Kailou Zhao, Li Yang, Xuejiao Wang, Quan Bai,
Fan Yang, Fei Wang We have explored a novel dual-function stationary phase
which combines both strong cation exchange (SCX) and hydrophobic interaction
chromatography (HIC) characteristics. The novel dual-function stationary phase
is based on porous and spherical silica gel functionalized with a ligand
containing sulfonic and benzyl groups capable of electrostatic and hydrophobic
interaction functionalities, which displays HIC character in a high salt
concentration, and IEC character in a low salt concentration in mobile phase
employed. As a result, it can be employed to separate proteins with SCX and HIC
modes, respectively. The resolution and selectivity of the dual-function
stationary phase were evaluated under both HIC and SCX modes with standard
proteins and can be comparable to that of conventional IEC and HIC columns. More
than 96% of mass and bioactivity recoveries of proteins can be achieved in both
HIC and SCX modes, respectively. The results indicated that the novel
dual-function column could replace two individual SCX and HIC columns for
protein separation. Mixed retention mechanism of proteins on this dual-function
column based on stoichiometric displacement theory (SDT) in LC was investigated
to find the optimal balance of the magnitude of electrostatic and hydrophobic
interactions between protein and the ligand on the silica surface in order to
obtain high resolution and selectivity for protein separation. In addition, the
effects of the hydrophobicity of the ligand of the dual-function packings and pH
of the mobile phase used on protein separation were also investigated in detail.
The results show that the ligand with suitable hydrophobicity to match the
electrostatic interaction is very important to prepare the dual-function
stationary phase, and a better resolution and selectivity can be obtained at pH
6.5 in SCX mode. Therefore, the dual-function column can replace two individual
SCX and HIC columns for protein separation and be used to set up two-dimensional
liquid chromatography with a single column (2DLC-1C), which can also be employed
to separate three kinds of active proteins completely, such as lysozyme,
ovotransferrin and ovalbumin from egg white. The result is very important not
only to the development of new 2DLC technology with a single column for
proteomics, but also to recombinant protein drug production for saving column
expense and simplifying the process in biotechnology.
Highlights
► We explored a bifunctional column with a ligand
containing sulfo and benzyl groups. ► This column can provide two operation
modes (HIC and SCX). ► High resolution and selectivity are obtained in both SCX
and HIC modes, respectively. ► This column can replace two corresponding single
mode (SCX and HIC mode) columns. ► Based on this bifunctional column, 2DLC was
established using only a single column.
Publication year:
2012 Source:Talanta Cédric Delporte, Thierry Franck, Caroline
Noyon, Damien Dufour, Alexandre Rousseau, Philippe Madhoun, Jean-Marc Desmet,
Didier Serteyn, Martine Raes, Joëlle Nortier, Michel Vanhaeverbeek, Nicole
Moguilevsky, Jean Nève, Luc Vanhamme, Pierre Van Antwerpen, Karim Zouaoui
Boudjeltia A high degree of uremia is common in patients with end-stage renal
disease and has been linked to the development of chronic inflammation and
cardiovascular diseases. In conditions where transplantation is not possible,
uremia can be reduced by hemodialysis although the repeated interventions have
been implicated in loss of renal function, partially as a result of chronic
inflammation and/or oxidative stress processes. In this context, it has been
suggested that myeloperoxidase (MPO) can contribute to the oxidative stress
during hemodialysis and to the cardiovascular risk. Protein damages due to MPO
activity have never been assessed during hemodialysis although two of its
reaction products, 3-chlorotyrosine and homocitrulline, are of interest. Indeed,
the first one is a specific product of MPO activity and the formation of the
second one could be catalyzed by MPO. In order to analyze these products in
plasma proteins, a total hydrolysis method followed by liquid chromatography
mass spectrometry analysis was developed. Different conditions of hydrolysis
were tested and the optimized procedure was assessed for complete hydrolysis and
artifactual chlorination. Finally, the method was used for analyzing
3-chlorotyrosine and homocitrulline in plasma proteins during a hemodialysis
session in fifteen patients and data were related to measurements of MPO
concentration and activity. Both increases in MPO activity and protein-bound
3-chlorotyrosine were observed, highlighting the involvement of MPO in oxidative
stress during hemodialysis and further demonstrating the link between
hemodialysis and cardiovascular diseases.
Highlights
► Simultaneous detection of protein-bound
3-chlorotyrosine and homocitrulline. ► Rapid protein acid hydrolysis assisted by
microwave oven. ► Method applied to a clinical situation: patients undergoing
hemodialysis. ► Myeloperoxidase activity increases during hemodialysis. ►
3-chlorotyrosine but not homocitrulline increases during
hemodialysis
Publication year:
2012 Source:Talanta Vikash Kumar, Amrita Chatterjee, Mainak
Banerjee A turn-on fluorescent probe for the detection of nitrite ion in
water is developed based on diazotization reaction of the amino group of the
probe in an acidic solution (pH 1). The probe responds selectively to nitrite
ion over various other anions with a turn-on type fluorogenic change from
colorless to orange by the formation of rhodamine B via an analyte triggered
fragmentation process. The fluorescence titration is complete within 1h with 1
equiv of nitrite ion. The probe is highly efficient, cost-effective and shows a
detection limit of 4.6ppb.
Highlights
► A rhodamine-based fluorescent probe is developed
for the detection of nitrite ions. ► The probe is highly selective to nitrite
ions in presence of many other anions. ► The fluorogenic detection level of
nitrite is found to be as low as 4.6ppb. ► The probe was successfully used for
detection of NO2¯ level in several real samples.
Publication year:
2012 Source:Talanta Jie Zhou, Qian Lu, Ying Tong, Wei Wei, Songqin
Liu A hairpin molecular beacon tagged with carboxyfluorescein in combination
with graphene oxide as a quencher reagent was used to detect the DNA damage by
chemical reagents. The fluorescence of molecular beacon was quenched sharply by
graphene oxide; while in the presence of its complementary DNA the quenching
efficiency decreased because their hybridization prevented the strong
adsorbability of molecular beacon on graphene oxide. If the complementary DNA
was damaged by a chemical reagent and could not form intact duplex structure
with molecular beacon, more molecular beacon would adsorb on graphene oxide
increasing the quenching efficiency. Thus, damaged DNA could be detected based
on different quenching efficiencies afforded by damaged and intact complementary
DNA. The damage effects of chlorpyrifos-methyl and three metabolites of styrene
such as mandelieaeids, phenylglyoxylieaeids and epoxystyrene on DNA were studied
as models. The method for detection of DNA damage was reliable, rapid and simple
compared to the biological methods.
Highlights
► DNA damage induced by several chemicals was
detected by a hairpin MB based on FRET. ► The method was rapid, simple, reliable
and sensitive. ► The method can be used to detect damaged DNA induced by other
reagents or factors.
Publication year:
2012 Source:Talanta Geng Leng, Hui Yin, Shaobo Li, Yong Chen,
Dezhong Dan A simple and fast solvent microextraction method termed
vortex-assisted liquid-liquid microextraction (VALLME) coupled with
high-performance liquid chromatography-vapor generation atomic fluorescence
spectrometry (HPLC-CVAFS) has been developed for the trace analysis of
methylmercury (MeHg+), ethylmercury (EtHg+) and inorganic
mercury (Hg2+) in sediment samples. Carbon tetrachloride was used as
collecting solvent for the extraction of mercury species from sediment by a
vortex-assisted extraction. In VALLME, 100μL 1% (m/v) L-Cysteine were used as
extraction solvent and were injected into 4mL carbon tetrachloride. The
extraction solvent dispersed into carbon tetrachloride under vigorously shaking
by a vortex agitator. The fine droplets could extract mercury species within few
minutes because of the shorter diffusion distance and larger specific surface
area. After centrifugation, the floating extractant phase restored its initial
single microdrop shape and was used for HPLC-CVAFS analysis. The parameters
affecting the extraction efficiency of the proposed VALLME such as extraction
solvent, vortex time, volumes of extraction solvent and salt addition etc. were
investigated. Under the optimum conditions, linearity was found in the
concentration range from 0.1 to 25ng g−1 for MeHg+, 0.2 to
65ng g−1 for EtHg+, and 0.1 to 30ng g−1 for
Hg2+. Coefficients of determination (R2) ranged from
0.9938 to 0.9972. The limits of detection (LODs, signal-to-noise ratio (S/N)=3)
were 0.028ng g−1 for MeHg+, 0.057ng g−1 for
EtHg+, and 0.029ng g−1 for Hg2+.
Reproducibility and recoveries were assessed by testing a series of 6 sediment
samples, which were spiked with different concentration levels. Finally, the
proposed method was successfully applied in analyses of real nature sediment
samples. In this work, VALLME was applied to the extraction of mercury species
in sediment samples for the first time. Using L-Cys as extraction solvent, the
extraction process is sensitive and environmentally friendly and could be
achieved within 3min.
Highlights
► VALLME was for the first time applied for the
extraction of mercury species in sediment.► Using L-Cys as extraction solvent,
the extraction is sensitive and environmentally friendly.► The extraction
process is achieved within 3min.
Publication year:
2012 Source:Talanta Fang Liu, Yan Zhang, Shenguang Ge, Juanjuan Lu,
Jinghua Yu, Xianrang Song, Su Liu A highly sensitive electrochemiluminescence
(ECL) immunosensor for the detection of prostate specific antigen (PSA) was
designed using biofunctionalized magnetic graphene nanosheets (G@Fe3O4) as
immunosensing probes and CdTe quantum dots coated silica nanospheres (Si/QDs) as
signal amplification labels. In this work, a sandwich-type immunosensor was
fabricated, which was assembled on the surface of indium tin oxide glass (ITO).
The analyte was detected in a home-made flow injection ECL (FI-ECL) cell through
the immunosensor. Owning to the signal amplification of G@Fe3O4 composite and
Si/QDs, the ECL measurement showed a great increase in detection signals
compared with the unamplified method. Under optimal conditions, a wide detection
range (0.003–50ngmL−1) and low detection limit
(0.72pgmL−1) were obtained through the sandwich-type immunosensor.
The proposed strategy successfully demonstrated a reproducible, specific, and
potent method that can be expanded to detect other proteins.
Highlights
► A sandwich-type electrochemluminence immunosensor
was fabricated. ► Magnetic graphene nanosheets were synthesized as immunosensing
probes. ► CdTe quantum dots coated silica nanospheres were used to amplify
signals. ► A home-made injection electrochemluminence cell was used as reaction
chamber.
Publication year:
2012 Source:Talanta Chunxiao Liu, Xinglei Zhang, Saijin Xiao, Bin
Jia, Shasha Cui, Jianbo Shi, Ning Xu, Xi Xie, Haiwei Gu, Huanwen Chen A
sensitive approach, based on semi-quantitative measurement of the characteristic
fragments in multi-stage extractive electrospray ionization mass spectrometry
(EESI-MSn), was developed for fast detection of trace levels of lead
in aqueous liquids including mineral water, lake water, tap water, energy
drinks, soft drinks, beer, orange juice, and tea. A disodium
ethylene-diamine-tetraacetic acid (EDTA) aqueous solution was electrosprayed to
produce negatively charged primary ions which then intersected the neutral
sample plume to generate anions of EDTA-Pb(II) complexes. The charged
EDTA-Pb(II) complexes were characterized with multistage collision induced
dissociation (CID) experiments. The limit of detection (LOD) using
EESI-MS3 was estimated to be at the level of 10–13 g/mL
for directly detecting lead in many of these samples. The linear dynamic range
was higher than 2 orders of magnitude. A single sample analysis could be
completed within 2min with reasonable semi-quantitative performance, e.g.,
relative standard deviations (RSDs) for deionized water were 4.6%-7.6% during 5
experimental runs (each of them had 10 repeated measurements). Coca-cola and
Huiyuan orange juice, representative beverage samples with complex matrices,
generated recovery rates of 91.5% and 129%, respectively. Our experimental data
demonstrated that EESI-MS is a useful tool for the fast detection of lead in
various solutions, and EESI-MS showed promises for fast screening of
lead-contaminated aqueous liquid samples.
Highlights
► EESI can directly detect lead in complex samples.
► EESI can semi-quantitatively measure the lead concentration. ► EESI may have
wide applications for food security and environmental science
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