Check out our New Publishers' Select for Free Articles

Analytica Chimica Acta (v.735, #)

Editorial Board (pp. iii).

Multi-elemental characterization of tunnel and road dusts in Houston, Texas using dynamic reaction cell-quadrupole-inductively coupled plasma–mass spectrometry: Evidence for the release of platinum group and anthropogenic metals from motor vehicles by Nicholas Spada; Ayse Bozlaker; Shankararaman Chellam (pp. 1-8).

Display Omitted► Analytical method for PGEs, main group, transition and rare earth metals developed. ► Comprehensive characterization of road and tunnel dust samples was accomplished. ► PGEs in dusts arise from autocatalyst attrition. ► Mobile sources also contributed to Cu, Zn, Ga, As, Mo, Cd, Sn, Sb, Ba, W and Pb. ► All other elements, including rare earths arose from crustal sources.Platinum group elements (PGEs) including Rh, Pd, and Pt are important tracers for vehicular emissions, though their measurement is often challenging and difficult to replicate in environmental campaigns. These challenges arise from sample preparation steps required for PGE quantitation, which often cause severe isobaric interferences and spectral overlaps from polyatomic species of other anthropogenically emitted metals. Consequently, most previous road dust studies have either only quantified PGEs or included a small number of anthropogenic elements. Therefore a novel analytical method was developed to simultaneously measure PGEs, lanthanoids, transition and main group elements to comprehensively characterize the elemental composition of urban road and tunnel dusts. Dust samples collected from the vicinity of high-traffic roadways and a busy underwater tunnel restricted to single-axle (predominantly gasoline-driven) vehicles in Houston, TX were analyzed for 45 metals with the newly developed method using dynamic reaction cell-quadrupole-inductively coupled plasma–mass spectrometry (DRC-q-ICP–MS). Average Rh, Pd and Pt concentrations were 152±52, 770±208 and 529±130ngg⁻¹ respectively in tunnel dusts while they varied between 6 and 8ngg⁻¹, 10 and 88ngg⁻¹ and 35 and 131ngg⁻¹ in surface road dusts. Elemental ratios and enrichment factors demonstrated that PGEs in dusts originated from autocatalyst attrition/abrasion. Strong evidence is also presented for mobile source emissions of Cu, Zn, Ga, As, Mo, Cd, Sn, Sb, Ba, W and Pb. However, all other elements including rare earths most likely arose from weathering, erosion and resuspension of crustal material. These are the first such detailed measurements in Houston, the largest city in TX and fourth largest in the United States. We posit that such investigations will assist in better understanding PGE concentrations in urban environments while providing elemental data necessary to better understand anthropogenic influences on their biogeochemical cycling.

Keywords: Platinum group elements; Road dust; Tunnel dust; Rare earth elements; ICP–MS; Houston

Application of quantum dots as analytical tools in automated chemical analysis: A review by Christian Frigerio; David S.M. Ribeiro; S. Sofia M. Rodrigues; Vera L.R.G. Abreu; João A.C. Barbosa; João A.V. Prior; Karine L. Marques; João L.M. Santos (pp. 9-22).

Display Omitted► Review on quantum dots application in automated chemical analysis. ► Automation by using flow-based techniques. ► Quantum dots in liquid chromatography and capillary electrophoresis. ► Detection by fluorescence and chemiluminescence. ► Electrochemiluminescence and radical generation.Colloidal semiconductor nanocrystals or quantum dots (QDs) are one of the most relevant developments in the fast-growing world of nanotechnology. Initially proposed as luminescent biological labels, they are finding new important fields of application in analytical chemistry, where their photoluminescent properties have been exploited in environmental monitoring, pharmaceutical and clinical analysis and food quality control. Despite the enormous variety of applications that have been developed, the automation of QDs-based analytical methodologies by resorting to automation tools such as continuous flow analysis and related techniques, which would allow to take advantage of particular features of the nanocrystals such as the versatile surface chemistry and ligand binding ability, the aptitude to generate reactive species, the possibility of encapsulation in different materials while retaining native luminescence providing the means for the implementation of renewable chemosensors or even the utilisation of more drastic and even stability impairing reaction conditions, is hitherto very limited. In this review, we provide insights into the analytical potential of quantum dots focusing on prospects of their utilisation in automated flow-based and flow-related approaches and the future outlook of QDs applications in chemical analysis.

Keywords: Nanocrystals; Quantum dots; Analytical chemistry; Flow analysis; Chromatography; Electrophoresis; Fluorescence; Chemiluminescence

Development of highly sensitive chemiluminescence enzyme immunoassay based on the anti-recombinant H_C subunit of botulinum neurotoxin type A monoclonal antibodies by Zhijia Liu; Chaojun Song; Yongming Li; Fei Liu; Kui Zhang; Yuanjie Sun; Haitao Li; Yuying Wei; Zhuwei Xu; Chunmei Zhang; Angang Yang; Zhikai Xu; Kun Yang; Boquan Jin (pp. 23-30).

Display Omitted► The rAH_C could elict highly protective antibody titer as vaccine. ► Two anti-rAH_C mAbs were selected to form the sensitive CLEIA for detecting BoNT/A. ► The CLEIA detecting BoNT/A is more sensitive than that of the ELISA reported.Botulinum neurotoxins (BoNTs) are the most poisonous substances ever known. The early detection of these toxins could bear more time for appropriate medical intervention. The standard method for detecting BoNTs is the mouse bioassay, which is time consuming (up to 4 days) and requires a large number of laboratory animals. The immunologic detection methods could detect the toxins within a day, but most of these methods are less sensitive compared with the mouse bioassay due to the lack of high-affinity antibodies. Recently, the recombinant H_C subunit of botulinum neurotoxin type A (rAH_C) was expressed as an effective vaccine against botulism, indicating that the rAH_C could be an effective immunogen that raises the monoclonal antibody (mAb) for detecting BoNT/A. After immunized BALB/c mice with rAH_C, 56 mAbs were generated. Two of these mAbs were selected to establish a highly sensitive sandwich chemiluminescence enzyme immunoassay (CLEIA), in which FMMU-BTA-49 and FMMU-BTA-22 were used as capture antibody and detection antibody, respectively. The calculated limit of detection (LOD) based on molecular weight of rAH_C and BoNT/A reached 0.45pgmL⁻¹. This CLEIA can be used in the detection of BoNT/A in matrices such as milk and beef extract. This method has 20–40 fold lower LOD than that of the mouse bioassay and takes only 3h to complete the detection, indicating that it can be used as a valuable method to detect and quantify BoNT/A.

Keywords: Abbreviations; CLEIA; chemiluminescence enzyme immunoassay; mAbs; monoclonal antibodies; rAH; _C; recombinat C-terminal of heavy chain of botulinum neurotoxin type A; BoNT/A; botulinum neurotoxin type ABotulinum neurotoxin type A; Chemiluminescence enzyme immunoassay; Recombinat C-terminal of heavy chain of botulinum neurotoxin type A; Detection; Sensitivity

Native and denatured forms of proteins can be discriminated at edge plane carbon electrodes by Veronika Ostatná; Hana Černocká; Katarzyna Kurzątkowska; Emil Paleček (pp. 31-36).

Display Omitted► Protein structure-sensitive oxidation signals depend on materials of carbon electrodes. ► Tracing the course of protein denaturation at edge plane pyrolytic graphite electrode. ► Picomoles of proteins are sufficient for voltammetric structure-sensitive analysis.In an attempt to develop a label-free electrochemical method for detection of changes in protein structures based on oxidizability of tyrosine and tryptophan residues we tested different types of carbon electrodes. We found that using edge plane pyrolytic graphite electrode (EPGE) we can discriminate between native and denatured forms of human serum albumin (HSA) and of other proteins, such as bovine and chicken serum albumin, aldolase and concanavalin. Treatment of natively unfolded α-synuclein with 8M urea resulted only in a small change in the tyrosine oxidation peak, in a good agreement with absence of highly ordered structure in this protein. Using square wave voltammetry with EPGE we were able to follow the course of HSA denaturation at different urea concentrations. The electrochemical denaturation curve agreed reasonably well with that based on intrinsic fluorescence of tyrosine and tryptophan. It can be expected that the electrochemical method will be applicable to a large number of proteins and may become useful in biomedicine and proteomics.

Keywords: Protein denaturation; Carbon electrodes; Edge plane pyrolytic graphite; Electrooxidation of proteins; Human serum albumin

Potentiometric stripping analysis of methyl and ethyl parathion employing carbon nanoparticles and halloysite nanoclay modified carbon paste electrode by Bankim J. Sanghavi; Gary Hirsch; Shashi P. Karna; Ashwini K. Srivastava (pp. 37-45).

Display Omitted► Determination of methyl parathion (MP) and ethyl parathion (EP). ► Potentiometric stripping analysis for quantitation of MP and EP. ► Halloysite nanoclay and carbon nanoparticles modified carbon paste electrode used as working electrode. ► Analysis of MP and EP in fruits, vegetables, water and soil samples. ► Halloysite nanoclay used as a modifier for the first time in electrochemistry.Carbon nanoparticles (CNPs) and halloysite nanoclay (HNC) modified carbon paste electrode (HNC–CNP–CPE) was developed for the determination of methyl parathion (MP) and ethyl parathion (EP). The electrochemical behavior of these molecules was investigated employing cyclic voltammetry (CV), chronocoulometry (CC), electrochemical impedance spectroscopy (EIS) and potentiometric stripping analysis (PSA). After optimization of analytical conditions employing this electrode at pH 5.0 in acetate buffer (0.1M), the peak currents were found to vary linearly with its concentration in the range of 1.55×10⁻⁹ to 3.67×10⁻⁶M and 1.21×10⁻⁹ to 4.92×10⁻⁶M for MP and EP, respectively. The detection limits (S/N=3) of 4.70×10⁻¹⁰M and 3.67×10⁻¹⁰M were obtained for MP and EP, respectively, using PSA. The prepared modified electrode showed several advantages such as simple preparation method, high sensitivity, very low detection limits and excellent reproducibility. The proposed method was employed for the determination of MP and EP in fruits, vegetables, water and soil samples.

Keywords: Methyl parathion; Ethyl parathion; Carbon nanoparticles; Halloysite nanoclay; Potentiometric stripping analysis

Liquid-phase microextraction in a microfluidic-chip – High enrichment and sample clean-up from small sample volumes based on three-phase extraction by María D. Ramos Payán; Henrik Jensen; Nickolaj Jacob Petersen; Steen Honoré Hansen; Stig Pedersen-Bjergaard (pp. 46-53).

Display Omitted► We demonstrate the first liquid-phase microextraction chip with flow conditions (LPME-chip). ► We demonstrate very high analyte enrichment from small sample volumes. ► We show an application of this LPME-chip for the study of drug metabolism.In this work, a microfluidic-chip based system for liquid-phase microextraction (LPME-chip) was developed. Sample solutions were pumped into the LPME-chip with a micro-syringe pump at a flow rate of 3–4μLmin⁻¹. Inside the LPME chip, the sample was in direct contact with a supported liquid membrane (SLM) composed of 0.2μL dodecyl acetate immobilized in the pores of a flat membrane of polypropylene (25μm thickness). On the other side of the SLM, the acceptor phase was present. The acceptor phase was either pumped at 1μLmin⁻¹ during extraction or kept stagnant (stop-flow). Amitriptyline, methadone, haloperidol, loperamide, and pethidine were selected as model analytes, and they were extracted from alkaline sample solution, through the SLM, and into 10mM HCl or 100mM HCOOH functioning as acceptor phase. Subsequently, the acceptor phase was either analyzed off-line by capillary electrophoresis for exact quantification, or on-line by UV detection or electrospray ionization mass spectrometry for time profiling of concentrations. The LPME-chip was found to be highly effective, and extraction efficiencies were in the range of 52–91%. When the flow of acceptor phase was turned off during extraction (stop-flow), analyte enrichment increased linearly with the extraction time. After 10min as an example, amitriptyline was enriched by a factor of 42 from only 30μL sample solution, and after 120min amitriptyline was enriched by a factor of 500 from 320μL sample solution. This suggested that the LPME-chip has great potentials for very efficient analyte enrichments from limited sample volumes in the future.

Keywords: Liquid-phase microextraction; Microfluidic-chip; Biological fluids; Enrichment; Electrospray ionization mass spectrometry

The application of an in vitro gastrointestinal extraction to assess the oral bioaccessibility of polycyclic aromatic hydrocarbons in soils from a former industrial site by Damien Lorenzi; Jane Entwistle; Mark Cave; Joanna Wragg; John R. Dean (pp. 54-61).

Display Omitted► Total/bioaccessible concentration of 16 PAHs assessed in former industrial site. ► Oral bioaccessibility was assessed using FOREhST method. ► Total PAH concentrations were compared with GAC (residential land use scenario). ► Levels of 7 PAHs could lead to an unacceptable risk to human health at this site.The total and bioaccessible concentration of 16 polycyclic aromatic hydrocarbons (PAHs) in soil from a former industrial site was investigated. Typical total concentrations across the sampling sites ranged from 1.5mgkg⁻¹ for acenaphthylene up to 243mgkg⁻¹ for fluoranthene. The oral bioaccessibility of PAHs in soil was assessed using an in vitro gastrointestinal extraction (Fed Organic Estimation human Simulation Test, FOREhST method). The oral bioaccessibility data indicated that fluorene, phenanthrene, chrysene, indeno(1,2,3-cd)pyrene and dibenzo(a,h)anthracene had the highest % bioaccessible fraction (based on their upper 75th percentile values being >60%) while the other PAHs had lower % bioaccessible fractions (means ranging between 35 and 59%). Significantly lower bioaccessibilities were determined for naphthalene. With respect to method validation and inter-laboratory comparison, the total and bioaccessible concentrations of benzo(a)anthracene, benzo(b)anthracene, benzo(k)fluoranthene, benzo(a)pyrene, indeno(1,2,3-cd)pyrene and dibenzo(a,h)anthracene was compared to published data derived using the same samples. The total PAH concentrations at the site were compared with generic assessment criteria (GAC) using the residential land use scenario (with plant uptake at 6% soil organic matter). Concentrations of 7 of the PAHs investigated within the soils could lead to an unacceptable risk to human health at this site.

Keywords: In vitro; gastrointestinal extraction; Health risk assessment; Generic assessment criteria; Polycyclic aromatic hydrocarbons; Gas chromatography–mass spectrometry

Fabrication of electrolytic cell for online post-column electrochemical derivatization in ion chromatography by Shuchao Wu; Wei Xu; Bingcheng Yang; Mingli Ye; Peimin Zhang; Chao Shen-Tu; Yan Zhu (pp. 62-68).

Display Omitted► An electrolytic cell including ruthenium modified titanium electrode was fabricated. ► Ion chromatography/electrochemical derivatization/fluorescence detection was developed. ► Strong oxidation capacity of this EC was obtained by using the Ru/Ti electrode with large surface area.An electrolytic cell (EC), composed of two ruthenium-plated titanium electrodes separated by cation-exchange membranes, was fabricated and evaluated for online postcolumn derivatization in ion chromatography (IC). Folic acid (FA) and methotrexate (MTX) were preliminarily used as prototype analytes to test the performance of EC. After separation by an anion exchange column, FA and MTX, which emit very weak fluorescence when excited, were electrochemically oxidized online in the anode chamber of the EC. The compounds with strong fluorescence, which are oxidation products, were detected by the fluorescence detector. The phosphate buffer solution (100mM KH₂PO₄) served as an optimal eluent for anion exchange chromatographic separation and a suitable supporting electrolyte for electro-oxidation, leading to ideal compatibility between IC separation and the postcolumn electrochemical derivatization. For the presently proposed method, the linear ranges were from 0.01mgL⁻¹ to 5mgL⁻¹ for both FA and MTX. The detection limits of FA and MTX were 1.8and 2.1μgL⁻¹, and the relative standard deviations (RSD, n=7) were 2.9% and 3.6%, respectively. The method was applied for the simultaneous determination of FA and MTX in the plasma of patients being treated for rheumatoid arthritis. The determination of MTX in the urine of the patients of diffuse large B cell lymphoma was also demonstrated.

Keywords: Electrolytic cell; Electrochemical derivatization; Ion chromatography; Fluorescence

Photoactivation by visible light of CdTe quantum dots for inline generation of reactive oxygen species in an automated multipumping flow system by David S.M. Ribeiro; Christian Frigerio; João L.M. Santos; João A.V. Prior (pp. 69-75).

Display Omitted► CdTe quantum dots generate free radical species upon exposure to visible radiation. ► A high power visible LED lamp was used as photoirradiation element. ► The laboratory-made LED photocatalytic unit was implemented inline in a MPFS. ► Free radical species oxidize luminol producing a strong chemiluminescence emission. ► Epinephrine scavenges free radical species quenching chemiluminescence emission.Quantum dots (QD) are semiconductor nanocrystals able to generate free radical species upon exposure to an electromagnetic radiation, usually in the ultraviolet wavelength range. In this work, CdTe QD were used as highly reactive oxygen species (ROS) generators for the control of pharmaceutical formulations containing epinephrine. The developed approach was based on the chemiluminometric monitoring of the quenching effect of epinephrine on the oxidation of luminol by the produced ROS. Due to the relatively low energy band-gap of this chalcogenide a high power visible light emitting diode (LED) lamp was used as photoirradiation element and assembled in a laboratory-made photocatalytic unit. Owing to the very short lifetime of ROS and to ensure both reproducible generation and time-controlled reaction implementation and development, all reactional processes were implemented inline by using an automated multipumping micro-flow system. A linear working range for epinephrine concentration of up to 2.28×10⁻⁶molL⁻¹ ( r=0.9953; n=5) was verified. The determination rate was about 79 determinations per hour and the detection limit was about 8.69×10⁻⁸molL⁻¹. The results obtained in the analysis of epinephrine pharmaceutical formulations by using the proposed methodology were in good agreement with those furnished by the reference procedure, with relative deviations lower than 4.80%.

Keywords: Quantum dots; Visible light photoirradiation; Reactive oxygen species; Chemiluminescence; Multipumping flow system; Epinephrine

Structural elucidation of molecular species of pacific oyster ether amino phospholipids by normal-phase liquid chromatography/negative-ion electrospray ionization and quadrupole/multiple-stage linear ion-trap mass spectrometry by Su Chen; Natalia A. Belikova; Papasani V. Subbaiah (pp. 76-89).

Display Omitted► Development of a simple and robust NPLC-NI-ESI/Q-TRAP-MSⁿ method for ω-3 aminophospholipidomics of marine animals. ► Establishment of a full fragmentation pathway for the structural differentiation of plasmenyl PS from plasmanyl PS. ► Structurally differentiate up to six isobaric species from a phosphatidylethanolamine molecule in the US pacific oysters.Although marine oysters contain abundant amounts of ether-linked aminophospholipids, the structural identification of the various molecular species has not been reported. We developed a normal-phase silica liquid chromatography/negative-ion electrospray ionization/quadrupole multiple-stage linear ion-trap mass spectrometric (NPLC-NI-ESI/Q-TRAP-MS³) method for the structural elucidation of ether molecular species of serine and ethanolamine phospholipids from marine oysters. The major advantages of the approach are (i) to avoid incorrect selection of isobaric precursor ions derived from different phospholipid classes in a lipid mixture, and to generate informative and clear MSⁿ product ion mass spectra of the species for the identification of the sn-1 plasmanyl or plasmenyl linkages, and (ii) to increase precursor ion intensities by “concentrating” lipid molecules of each phospholipid class for further structural determination of minor molecular species. Employing a combination of NPLC-NI-ESI/MS³ and NPLC-NI-ESI/MS², we elucidated, for the first time, the chemical structures of docosahexaenoyl and eicosapentaenoyl plasmenyl phosphatidylserine (PS) species and differentiated up to six isobaric species of diacyl/alkylacyl/alkenylacyl phosphatidylethanolamine (PE) in the US pacific oysters. The presence of a high content of both omega-3 plasmenyl PS/plasmenyl PE species and multiple isobaric molecular species isomers is the noteworthy characteristic of the marine oyster. The simple and robust NPLC-NI-ESI/MSⁿ-based methodology should be particularly valuable in the detailed characterization of marine lipid dietary supplements with respect to omega-3 aminophospholipids.

Keywords: Abbreviations; NPLC-NI-ESI/Q-TRAP-MS; normal-phase silica liquid chromatography/negative-ion electrospray ionization/quadrupole multiple-stage linear ion-trap mass spectrometry; PS; phosphatidylserine; PE; phosphatidylethanolamine; LysoPE; lysophosphatidylethanolamine; MTBE; methyl tert-butyl etherEther phospholipids; Ether phosphatidylserine; Ether phosphatidylethanolamine; LC/Q-TRAP-MS; ³; US pacific oyster; Omega 3 phospholipids; Omega 3 lipid dietary supplement

Layer-by-layer immobilization of carbon dots fluorescent nanomaterials on single optical fiber by Helena M.R. Gonçalves; Abel J. Duarte; Frank Davis; Seamus P.J. Higson; Joaquim C.G. Esteves da Silva (pp. 90-95).

Display Omitted► Fluorescent single fiber optic sensor. ► Carbon dots fluorescent nanoparticles. ► Fiber optic carbon dot based Hg(II) sensor. ► Sensor immobilized by the layer-by-layer technique.We report within this paper the development of a fiber-optic based sensor for Hg(II) ions. Fluorescent carbon nanoparticles were synthesized by laser ablation and functionalized with PEG₂₀₀ and N-acetyl-l-cysteine so they can be anionic in nature. This characteristic facilitated their deposition by the layer-by-layer assembly method into thin alternating films along with a cationic polyelectrolyte, poly(ethyleneimine). Such films could be immobilized onto the tip of a glass optical fiber, allowing the construction of an optical fluorescence sensor. When immobilized on the fiber-optic tip, the resultant sensor was capable of selectively detecting sub-micromolar concentrations of Hg(II) with an increased sensitivity compared to carbon dot solutions. The fluorescence of the carbon dots was quenched by up to 44% by Hg(II) ions and interference from other metal ions was minimal.

Keywords: Carbon dots; Nanoparticles; Layer-by-layer immobilization; Single optical fiber; Mercury sensor

Synthesis and photophysical properties of water-soluble sulfonato-Salen-type Schiff bases and their applications of fluorescence sensors for Cu²⁺ in water and living cells by Li Zhou; Peiying Cai; Yan Feng; Jinghui Cheng; Haifeng Xiang; Jin Liu; Di Wu; Xiangge Zhou (pp. 96-106).

Display Omitted► Sulfonate groups ensure good stability and solubility in water. ► Sulfonate groups have little effect on the photophysical properties. ► This is confirmed by the TD-DFT calculations and experimental results. ► The strong blue, green, or orange fluorescence is selectively quenched by Cu²⁺. ► The ligands are sensitive fluorescence sensors for Cu²⁺ in water and living cells.A series of water-soluble sulfonato-Salen-type ligands derived from different diamines including 1,2-ethylenediamine (Et-1–Et-4), 1,2-cyclohexanediamine (Cy-1 andCy-2), 1,2-phenylenediamine (Ph-1–Ph-3 andPhMe-1–PhMe-4), and dicyano-1,2-ethenediamine (CN-1) has been designed and prepared. Sulfonate groups of ligands ensure good stability and solubility in water without affecting their excited state properties. These ligands exhibit strong UV/Vis-absorption and blue, green, or orange fluorescence. Time-dependent-density functional theory calculations have been undertaken to reveal the influence of ligand nature, especially sulfonate groups, on the frontier molecular orbitals. Since their fluorescence is selectively quenched by Cu²⁺, the sulfonato-Salen-type ligands can be used as highly selective and sensitive turn-off fluorescence sensors for the detection of Cu²⁺ in water and fluorescence imaging in living cells.

Keywords: Keyword; Salen; Schiff base; Cu; ²⁺; fluorescence sensor; Water soluble; Sulfonate group; TD-DFT calculation

Development of an oxidative dehydrogenation-based fluorescent probe for Cu²⁺ and its biological imaging in living cells by Jiangli Fan; Xiaojian Liu; Mingming Hu; Hao Zhu; Fengling Song; Xiaojun Peng (pp. 107-113).

Display Omitted► The fluorescent probe contains an N, O and S tridentate ligand. ► The probe is simple but highly sensitive and selective toward Cu²⁺. ► The mechanism is based on the Cu²⁺-promoted dehydrogenation of amine in different organic and aqueous solutions. ► It was successfully applied to visualize Cu²⁺ in living cells.Based on a boron dipyrromethene (BODIPY) derivative containing an N, O and S tridentate ligand, a Cu²⁺ fluorescent probeBTCu was developed. The detection mechanism was verified as Cu²⁺-promoted oxidative dehydrogenation of an amine moiety, leading to a formation of a fluorescent Cu⁺–Schiff base complex. FreeBTCu exhibited a maximum absorption wavelength at 496nm, and a very weak maximum emission at 511nm. Upon addition of various metals ions, it showed large fluorescence enhancement toward Cu²⁺ (417-fold in MeCN and 103-fold in MeCN/HEPES solution, respectively) with high selectivity. The detection limits are as low as 1.74×10⁻⁸M and 4.96×10⁻⁸M in the two different solutions, respectively. AndBTCu could work in a wide pH range with an extraordinary low p K_a of 1.21±0.06. Using fluorescence microscopy, the probe was shown to be capable of penetrating into living cells and imaging intracellular Cu²⁺ changes.

Keywords: BODIPY; Fluorescent probe; Cu; ²⁺; Oxidative dehydrogenation; Living cells

Quantum dot-enhanced detection of dual short RNA sequences via one-step template-dependent surface hybridization by Wenqing Song; Xue Qiu; Choiwan Lau; Jianzhong Lu (pp. 114-120).

A novel multiplexed method for short RNA detection is reported that employed a design strategy in which quantum dots functionalized reporter DNA were used to capture a short single-stranded RNA sequence from a target solution and then to specifically adsorb onto a common capture probe-modified 96-well plate via a one-step template-dependent, surface hybridization for simultaneous fluorescence detection.Display Omitted► A ligase-free sensor was demonstrated for the specific detection of dual short RNA. ► The method was sensitive and simultaneous. ► Quantum dots-modified reporter probes could increase the melting temperature. ► Quantum dots functionalized reporter DNA hybridized with capture DNA and target RNA. ► Target RNA was captured via a one-step template-dependent hybridization.A novel multiplexed method for short RNA detection is reported that employs a design strategy in which capture and reporter probes anneal to each other in the presence of a short RNA target via the formation of a stable three-component complex. Quantum dots (QDs) functionalized with reporter DNA are thus specifically bound onto a capture probe-modified 96-well plate by one-step hybridization for simple RNA detection. In comparison with conventional organic dye-modified reporter probes, the use of reporter DNA-modified QD conjugates increase the melting temperature and lead to the detection of short RNA without the need for a ligation reaction. Moreover, QD properties allow multiple short RNA sequences to be simultaneously determined via rapid and simple one-step hybridization, as exemplified herein. The present results clearly demonstrate that this new strategy can be used to detect dual-short RNA sequence at concentrations of 10pM in 100μL.

Keywords: Quantum dots; Short RNA; One-step hybridization; Ligase-free reaction

Sections

Personal tools

Analytica Chimica Acta (v.735, #)

Sections

Personal tools

Local resources

Analytica Chimica Acta (v.735, #)