Check out our New Publishers' Select for Free Articles

Analytica Chimica Acta (v.737, #)

Editorial Board (pp. iii).

Recent advances in ZnO nanostructures and thin films for biosensor applications: Review by Sunil K. Arya; Shibu Saha; Jaime E. Ramirez-Vick; Vinay Gupta; Shekhar Bhansali; Surinder P. Singh (pp. 1-21).

ZnO nanostructures have shown binding of biomolecules in desired orientation with improved conformation and high biological activity, resulting in enhanced sensing characteristics. Furthermore, their compatibility with complementary metal oxide semiconductor technology for constructing integrated circuits makes them suitable candidate for future small integrated biosensor devices. This review highlights various approaches to synthesize ZnO nanostructures and thin films, and their applications in biosensor technology.Display Omitted► This review highlights various approaches to synthesize ZnO nanostructures and thin films. ► Article highlights the importance of ZnO nanostructures as biosensor matrix. ► Article highlights the advances in various biosensors based on ZnO nanostructures. ► Article describes the potential of ZnO based biosensor for new generation healthcare devices.Biosensors have shown great potential for health care and environmental monitoring. The performance of biosensors depends on their components, among which the matrix material, i.e., the layer between the recognition layer of biomolecule and transducer, plays a crucial role in defining the stability, sensitivity and shelf-life of a biosensor. Recently, zinc oxide (ZnO) nanostructures and thin films have attracted much interest as materials for biosensors due to their biocompatibility, chemical stability, high isoelectric point, electrochemical activity, high electron mobility, ease of synthesis by diverse methods and high surface-to-volume ratio. ZnO nanostructures have shown the binding of biomolecules in desired orientations with improved conformation and high biological activity, resulting in enhanced sensing characteristics. Furthermore, compatibility with complementary metal oxide semiconductor technology for constructing integrated circuits makes ZnO nanostructures suitable candidate for future small integrated biosensor devices. This review highlights recent advances in various approaches towards synthesis of ZnO nanostructures and thin films and their applications in biosensor technology.

Keywords: ZnO nanostructures; Biosensor; Nanorods; Nanoflowers; Electrochemical

Magnetic Fe₃O₄@Au composite-enhanced surface plasmon resonance for ultrasensitive detection of magnetic nanoparticle-enriched α-fetoprotein by Ru-Ping Liang; Gui-Hong Yao; Li-Xia Fan; Jian-Ding Qiu (pp. 22-28).

Display Omitted► We report an amplification technique using Fe₃O₄@Au MNPs for an SPR bioassay. ► Fe₃O₄@Au MNPs can function as an amplifier to increase the SPR signal. ► Sensitive detection of AFP is achieved via the purification/amplification protocol. ► This strategy has great potential for detecting other biomolecules of interest.Small molecules or analytes present at low concentrations are difficult to detect directly using conventional surface plasmon resonance (SPR) techniques because only small changes in the refractive index of the medium are typically induced by the binding of these analytes. Here, we present an amplification technique using core–shell Fe₃O₄@Au magnetic nanoparticles (MNPs) for an SPR bioassay. To evaluate this amplification effect, a novel SPR sensor based on a sandwich immunoassay was developed to detect α-fetoprotein (AFP) by immobilizing a primary AFP antibody (Ab₁) on the surface of a 3-mercapto-1-propanesulfonate/chitosan-ferrocene/Au NP (MPS/CS-Fc/Au NP) film employing Fe₃O₄@Au–AFP secondary antibody conjugates (Fe₃O₄@Au–Ab₂) as the amplification reagent. The stepwise fabrication of the biosensor was characterized using UV-vis spectroscopy, electrochemical impedance spectroscopy, and cyclic voltammetry. A calibration curve of Fe₃O₄@Au–Ab₂ conjugates amplification for AFP detection was obtained to yield a correlation in the range of 1.0–200.0ngmL⁻¹ with a detection limit of 0.65ngmL⁻¹, and a significant increase in sensitivity was therefore afforded through the use of Fe₃O₄@Au–Ab₂ conjugates as an amplifier. This magnetic separation and amplification strategy has great potential for the detection of other biomolecules of interest with low interference and high sensitivity by changing the antibody label used in the Fe₃O₄@Au–antibody conjugates.

Keywords: Surface plasmon resonance; Fe; ₃; O; ₄; @Au magnetic nanoparticle; α-Fetoprotein; signal enhancement

Disposable amperometric magneto-immunosensor for direct detection of tetracyclines antibiotics residues in milk by Felipe Conzuelo; María Gamella; Susana Campuzano; A. Julio Reviejo; José M. Pingarrón (pp. 29-36).

Display Omitted► First disposable amperometric magnetoimmunosensor for detection of TCs in milk. ► Immunosensor with great sensitivity and broad specificity for TCs detection. ► LODs achieved for all the TCs tested below the MRLs. ► Useful and affordable alternative to classical assays for TCs’ detection.The preparation and performance of a disposable amperometric magneto-immunosensor, involving the use of a selective capture antibody immobilized on the surface of protein G-functionalized magnetic beads (ProtG-MBs) and screen-printed carbon electrodes (SPCEs), for the specific detection and quantification of tetracyclines (TCs) residues in milk is reported. A direct competitive immunoassay using a tracer with horseradish peroxidase (HRP) for the enzymatic labeling was performed. The amperometric response measured at −0.2V vs. the silver pseudo-reference electrode of the SPCE upon the addition of H₂O₂ in the presence of hydroquinone (HQ) as redox mediator was used as transduction signal. The developed methodology showed very low limits of detection (in the low ppb level) for 4 tetracycline antibiotics tested in untreated milk samples, and a good selectivity against other antibiotic residues frequently detected in milk and dairy products. The usefulness of the magneto-immunosensor was demonstrated by analyzing UHT whole milk samples spiked with 44ngmL⁻¹ tetracycline (TC) as well as a reference milk containing a certified oxytetracycline (OTC) content. These features, together with the short analysis time (30min), the simplicity, and easy automation and miniaturization of the required instrumentation make the developed methodology a promising alternative in the development of devices for on-site analysis.

Keywords: Tetracycline antibiotics; Magnetic beads; Milk; Screen-printed carbon electrodes

Chemical images of marine bio-active compounds by surface enhanced Raman spectroscopy and transposed orthogonal partial least squares (T-OPLS) by Aamer Abbas; Mats Josefson; Göran M. Nylund; Henrik Pavia; Katarina Abrahamsson (pp. 37-44).

Display Omitted► T-OPLS imaging. ► Chemical images of algal antibacterial agent. ► Mapping by SERS with internal standard.Surface enhanced Raman spectroscopy combined with transposed Orthogonal Partial Least Squares (T-OPLS) was shown to produce chemical images of the natural antibacterial surface-active compound 1,1,3,3-tetrabromo-2-heptanone (TBH) on Bonnemaisonia hamifera. The use of gold colloids functionalised with the internal standard 4-mercapto-benzonitrile (MBN) made it possible to create images of the relative concentration of TBH over the surfaces. A gradient of TBH could be mapped over and in the close vicinity of the B. hamifera algal vesicles at the attomol/pixel level.T-OPLS produced a measure of the spectral correlation for each pixel of the hyperspectral images whilst not including spectral variation that was linearly independent of the target spectrum. In this paper we show the possibility to retrieve specific spectral information with a low magnitude in a complex matrix.

Keywords: Surface enhanced Raman spectroscopy; Bonnemaisonia hamifera; 1,1,3,3-Tetrabromo-2-heptanone; OPLS; Transposed orthogonal partial least squares; Hyperspectral image; Spectral imaging

Non-contact detection of chemical warfare simulant triethyl phosphate using PM-IRRAS by Annia H. Kycia; Mansoor Vezvaie; Vlad Zamlynny; Jacek Lipkowski; Michael W.P. Petryk (pp. 45-54).

Display Omitted► PM-IRRAS was employed to detect the chemical warfare agent (CWA) simulant triethyl phosphate. ► The targeted CWAs (G and V-series nerve agents) are characterized by phosphoric group vibrations. ► The PO and (P)OC bands were used to determine the experimental limit of detection (LoD). ► The estimated LoD is 300 times lower than the typical lethal dose of G and V-series nerve agents. ► PM-IRRAS shows promise as a technology of an optically-based system for non-contact detection of persistent CWAs.Polarization modulation-infrared reflection absorption spectroscopy (PM-IRRAS) was employed to detect the chemical warfare agent (CWA) simulant triethyl phosphate (TEP) on gold, as well as on US military paint, i.e., chemical agent resistant coating (CARC). The targeted CWAs (G and V-series nerve agents) are characterized by phosphoric group vibrations present in the 1200cm⁻¹ region. TEP displays two prominent peaks at 1268cm⁻¹ and 1036cm⁻¹ corresponding to PO and (P)OC vibrations, respectively. A droplet of TEP solution in cyclohexane was deposited on gold and CARC substrates and after solvent evaporation PM-IRRAS spectra were collected in the 1200cm⁻¹ region. The integrated peak area of the PO and (P)OC vibrations was used to construct calibration curves and to determine the experimental limit of detection (LoD). In the case of gold as the substrate the estimated LoD of ∼0.48μg and 1.23μg was obtained for the PO and (P)OC vibrations, respectively. In the case of CARC, a LoD of 24μg was determined. These detection limits are at least 3 orders of magnitude lower than the typical lethal dose of G and V-series nerve agents, demonstrating potential of PM-IRRAS for non-contact detection of these CWAs.

Keywords: Abbreviations; PM-IRRAS; polarization modulation-infrared reflection absorption spectroscopy; TEP; triethyl phosphate; TMP; trimethyl phosphate; LoD; limit of detection; CWA; chemical warfare agent; CARC; chemical agent resistant coating; PEM; photoelastic modulator; SSD; synchronous sampling demodulatorPolarization modulation-infrared reflection absorption spectroscopy; Triethyl phosphate; Chemical warfare agents

Modification of glassy carbon electrode with a polymer/mediator composite and its application for the electrochemical detection of iodate by Ta-Jen Li; Chia-Yu Lin; A. Balamurugan; Chung-Wei Kung; Jen-Yuan Wang; Chih-Wei Hu; Chun-Chieh Wang; Po-Yen Chen; R. Vittal; Kuo-Chuan Ho (pp. 55-63).

Display Omitted► FAD and PEDOT are combined to modify the glassy carbon electrode for IO₃⁻ sensing. ► The doping of FAD into PEDOT matrix can almost be viewed as an irreversible process. ► The optimal cycle number for preparing the GCE/PEDOT/FAD electrode is found to be 9. ► The detection limit of the GCE/PEDOT/FAD electrode for IO₃⁻ is found to be 0.16μM. ► The GCE/PEDOT/FAD electrode possesses enough selectivity toward IO₃⁻.A modified glassy carbon electrode was prepared by depositing a composite of polymer and mediator on a glassy carbon electrode (GCE). The mediator, flavin adenine dinucleotide (FAD) and the polymer, poly(3,4-ethylenedioxythiophene) (PEDOT) were electrochemically deposited as a composite on the GCE by applying cyclic voltammetry (CV). This modified electrode is hereafter designated as GCE/PEDOT/FAD. FAD was found to significantly enhance the growth of PEDOT. Electrochemical quartz crystal microbalance (EQCM) analysis was performed to study the mass changes in the electrode during the electrodeposition of PEDOT, with and without the addition of FAD. The optimal cycle number for preparing the modified electrode was determined to be 9, and the corresponding surface coverage of FAD ( Γ_FAD) was ca. 5.11×10⁻¹⁰molcm⁻². The amperometric detection of iodate was performed in a 100mM buffer solution (pH 1.5). The GCE/PEDOT/FAD showed a sensitivity of 0.78μAμM⁻¹cm⁻², a linear range of 4–140μM, and a limit of detection of 0.16μM for iodate. The interference effects of 250-fold Na⁺, Mg²⁺, Ca²⁺, Zn²⁺, Fe²⁺, Cl⁻, NO₃⁻, I⁻, SO₄²⁻ and SO₃²⁻, with reference to the concentration of iodate were negligible. The long-term stability of GCE/PEDOT/FAD was also investigated. The GCE/PEDOT/FAD electrode retained 82% of its initial amperometric response to iodate after 7 days. The GCE/PEDOT/FAD was also applied to determine iodate in a commercial salt.

Keywords: Amperometric detection; Electrochemical quartz crystal microbalance; Flavin adenine dinucleotide; Iodate; Modified electrode; Poly(3,4-ethylenedioxythiophene)

Relationship between ammonia sensing properties of polyaniline nanostructures and their deposition and synthesis methods by H. Kebiche; D. Debarnot; A. Merzouki; F. Poncin-Epaillard; N. Haddaoui (pp. 64-71).

.Display Omitted► Dependence of nanostructure morphology on the deposition process. ► Interest of nanostructures for gas detection compared to conventional polyaniline. ► Importance of a high surface area on the improved gas sensor performances. ► Better performances of nanostructures synthesized by rapid mixing polymerization. ► Better stability of CSA-doped polyaniline.The ammonia absorption properties of polyaniline nanostructures are studied in terms of sensitivity, response and recovery times and stability. These characteristics are obtained by measuring, at room temperature, the absorbance variations at 632nm. The nanostructures are synthesized either by interfacial or rapid or dropwise polymerizations with the oxidant-to-monomer mole ratio equals to 0.5 or 1. The influence of the deposition method ( in-situ or drop-coating technique) as well as the nature of the dopant (HCl, CSA or I₂) on the gas detection properties are also studied. The results show a strong dependence of the morphology on the deposition method, the in-situ technique leads to the best sensitivity and response time. For this deposition method, the nanostructures sensitivity, response time and regeneration rate depend on the synthesis method, the dopant and the mole ratio. The ageing effect after 8 months under ambient conditions and the mechanism of interaction between the polyaniline nanostructures and ammonia molecules are also presented.

Keywords: Polyaniline; Nanostructures; Chemical synthesis; Ammonia sensing

Development of a potassium-selective optode for hydroponic nutrient solution monitoring by Matthew Bamsey; Alain Berinstain; Michael Dixon (pp. 72-82).

Display Omitted► Potassium-selective bulk optode for hydroponic nutrient solution monitoring. ► Summary review of all published potassium bulk optodes. ► Description of developed absorption-based fibre optic instrument. ► Characterization of sensor selectivity, influence of pH/temperature, lifetime, etc. ► Overview of specific space-based and terrestrial technology transfer benefits.Highly efficient and reliable plant growth such as that required in biological life support systems for future space-based missions can be better achieved with knowledge of ion concentrations within the hydroponic nutrient solution. This paper reports on the development and application of ion-selective bulk optodes to plant growth systems. Membranes for potassium-selective sensing are reported that have been tailored so that their dynamic range is centred on potassium activities within typical nutrient solution recipes. The developed sensors have been shown to exhibit a potassium activity measuring range from 0.134 to 117mM at pH 6.0. These bulk optodes show full scale response on the order of several minutes. They show minimal interference to other cations and meet worst-case selectivity requirements for potassium monitoring in the considered half strength Hoagland solution. When continuously immersed in nutrient solution, these sensors demonstrated predicable lifetimes on the order of 50h. The developed instrument for absorption-based measurements including light source, mini-spectrometer and optode probe is presented. Custom instrument control and monitoring software including a spectral normalization procedure, use of a dual-wavelength absorbance ratio technique and automatic adjustment for pH variation result in an instrument that is self-calibrating and one that can account for effects such as light source fluctuations, membrane thickness variations and a variety of other factors. The low mass, low volume nature of bulk optode sensing systems, make them a promising technology for future space-based plant production systems. Their low-cost and technology transfer potential suggest that they could provide terrestrial growers a new and reliable mechanism to obtain ion-selective knowledge of their nutrient solution, improving yields, reducing costs and aiding in compliance to continually more stringent environmental regulation.

Keywords: Ion-selective membrane; Bulk optode; Bulk optrode; Potassium sensor; Hydroponic nutrient solution; Biological life support

A generic approach for expanding homolog-targeted residue screening of sulfonamides using a fast matrix separation and class-specific fragmentation-dependent acquisition with a hybrid quadrupole-linear ion trap mass spectrometer by Chunlin Huang; Bin Guo; Xiaoying Wang; Jie Li; Weitao Zhu; Bo Chen; Shan Ouyang; Shouzhuo Yao (pp. 83-98).

Display Omitted► Generic homolog-targeted screening approach for multi-residual sulfonamide analogs. ► Single-tube extraction/partitioning-multifunction adsorption cleanup for direct injection. ► Class-specific fragmentation for expanding coverage of N⁴-acetyl and NOH metabolites. ► PreS–IDA–EPI in LC–QqLIT for simultaneous screening and confirmation of real samples.A generic and efficient homolog-targeted approach was used to expand screening and detection of target class of sulfonamides and structural analogs, based on a fast single-tube extraction/partitioning-multifunction adsorption cleanup (SEP/MAC) for class-specific fragmentation-dependent acquisition with a liquid chromatography–hybrid triple-quadrupole linear ion trap mass spectrometer (LC–QqLIT). By combining the two-stage process conducted in a single tube as one-pot protocol, the straightforward SEP/MAC procedure was optimized to offer clean extracts with reasonable recovery (71–109% with RSDs<20%) and decreased matrix interferences (−9 to 19%) of multiresidual sulfonamide extraction from different tissue samples. The novel use of neutral loss scan of 66Da (NLS) or precursor ion scanning of m/z 108 (PreS) in positive ion mode was found to achieve more comprehensive coverage of protonated molecular ions of a wide array of sulfonamides including N⁴-acetyl and hydroxylamine metabolites plus their possible dimers. Moreover, the PreS-triggered automatically enhanced product ion spectral acquisition enabled simultaneous screening, profiling and confirmation of an unlimited number of analytes belonging to the sulfonamide class within a single analysis. The validation and application results of the generic SEP/MAC-based LC–QqLIT strategy consistently demonstrated favorable performances with acceptable accuracy (67–116%), precision (RSDs<25%), and sensitivity (LOQs≤7.5ngg⁻¹) to meet the acceptance criteria for all the sulfonamide–tissue combinations. Thus, the integration of the matrix-independent SEP/MAC procedure and the multiparameter matching algorithm with the unit-resolution LC–QqLIT instrument can serve as a valuable semi-targeted discovery strategy for rapid screening and reliable quantitative/confirmatory analysis of real samples.

Keywords: Sulfonamides; Multi-residue; Dispersive solid-phase extraction; Animal tissues; Triple-quadrupole linear ion trap mass spectrometer; Semi-targeted screening

Analysis of four alkaloids of Coptis chinensis in rat plasma by high performance liquid chromatography with electrochemical detection by Lihong Liu; Zilin Chen (pp. 99-104).

Display Omitted► Sensitive and precise HPLC method with electrochemical detection. ► Simultaneous determination of four alkaloids in Rhizoma Coptidis by LC-ECD. ► Highly sensitive analysis of jatrorrhizine, coptisine, palmatine and berberine in rat plasma after oral administration. ► Elimination of interference from endogenous components.A sensitive and precise high performance liquid chromatography (HPLC)-electrochemical detection (ECD) method has been developed for the simultaneous determination of four isoquinoline alkaloids including berberine, jatrorrhizine, coptisine and palmatine in Chinese medicine Coptis chinensis. The typical HPLC analysis was performed on WondaSil^® C18-WR column (250×4.6mm, 5μm) with the mobile phase comprising 40mM phosphate buffer (pH 7.0)–acetonitrile (40:60, v/v) at the flow rate of 0.8mLmin⁻¹. The electrochemical detection employed a three electrode system with a bare glassy carbon electrode at +1.3V versus the Ag/AgCl reference electrode. The limits of detection (LODs) of four alkaloids ranged from 0.01 to 0.03μmolL⁻¹ and the LOD of berberine was 80 times lower than LOD obtained by UV detection. The rat plasma samples were assayed after oral administration of the traditional Chinese medicine Coptis chinensis by the proposed HPLC-ECD method. The recoveries of this method were ranging from 88.0 to 116%, with the relative standard deviation lower than 3.1% for intra-day precision and 5.7% for inter-day precision. These results show that HPLC-ECD is a useful tool for the quality control of herbal medicine Coptis chinensis and also for pharmacokinetic studies.

Keywords: Berberine; High performance liquid chromatography; Electrochemical detection; Plasma; Coptis chinensis

Sections

Personal tools

Analytica Chimica Acta (v.737, #)

Sections

Personal tools

Local resources

Analytica Chimica Acta (v.737, #)