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Analytica Chimica Acta (v.715, #)
Functionalized gold nanoparticle supported sensory mechanisms applied in detection of chemical and biological threat agents: A review by Venkata K.K. Upadhyayula (pp. 1-18).
Display Omitted► Smart sensors are needed for detection of chemical and biological threat agents. ► Smart sensors detect analytes with rapid speed, high sensitivity and selectivity. ► Functionalized gold nanoparticles (GNPs) can potentially smart sense threat agents. ► Functionalized GNPs support multiple analytical methods for sensing threat agents. ► Threat agents of all types can be detected using functionalized GNPs.There is a great necessity for development of novel sensory concepts supportive of smart sensing capabilities in defense and homeland security applications for detection of chemical and biological threat agents. A smart sensor is a detection device that can exhibit important features such as speed, sensitivity, selectivity, portability, and more importantly, simplicity in identifying a target analyte. Emerging nanomaterial based sensors, particularly those developed by utilizing functionalized gold nanoparticles (GNPs) as a sensing component potentially offer many desirable features needed for threat agent detection. The sensitiveness of physical properties expressed by GNPs, e.g. color, surface plasmon resonance, electrical conductivity and binding affinity are significantly enhanced when they are subjected to functionalization with an appropriate metal, organic or biomolecular functional groups. This sensitive nature of functionalized GNPs can be potentially exploited in the design of threat agent detection devices with smart sensing capabilities. In the presence of a target analyte (i.e., a chemical or biological threat agent) a change proportional to concentration of the analyte is observed, which can be measured either by colorimetric, fluorimetric, electrochemical or spectroscopic means. This article provides a review of how functionally modified gold colloids are applied in the detection of a broad range of threat agents, including radioactive substances, explosive compounds, chemical warfare agents, biotoxins, and biothreat pathogens through any of the four sensory means mentioned previously.
Keywords: Functionalized gold nanoparticles; Chemical and biological threat agents; Colorimetric sensors; Fluorimetric sensors; Electrochemical sensors; Spectroscopic sensor
Ionic liquid-modified materials for solid-phase extraction and separation: A review by Lorena Vidal; Marja-Liisa Riekkola; Antonio Canals (pp. 19-41).
Display Omitted► Ionic liquids modified materials present excellent properties for extraction and separation. ► Covalently bonded ionic liquid looses the liquid state but maintains the dual nature properties. ► Silica and polymers have been mainly the materials modified by ionic liquids. ► The use of ionic liquid in SPE is reviewed for first time. ► This is the first review just focused on covalently modified materials by ionic liquid.In recent years, materials science has propelled to the research forefront. Ionic liquids with unique and fascinating properties have also left their footprints to the developments of materials science during the last years. In this review we highlight some of their recent advances and provide an overview at the current status of ionic liquid-modified materials applied in solid-phase extraction, liquid and gas chromatography and capillary electrochromatography with reference to recent applications. In addition, the potential of ionic liquids in the modification of capillary inner wall in capillary electrophoresis is demonstrated. The main target material modified with ionic liquids is silica, but polymers and monoliths have recently joined the studies. Although imidazolium is still clearly the most commonly used ionic liquid for the covalently modification of materials, the exploitation of pyridinium and phosphonium will most probably increase in the future.
Keywords: Ionic liquid; Modified materials; Solid-phase extraction; Gas chromatography; Liquid chromatography; Capillary electrophoresis; Capillary electrochromatography
Detection of an aberrant methylation of CDH4 gene in PCR product by ferrocenylnaphthalene diimide-based electrochemical hybridization assay by Shinobu Sato; Masato Tsueda; Yusuke Kanezaki; Shigeori Takenaka (pp. 42-48).
Display Omitted► Hybridization efficiency with a DNA probe on the electrode was clarified. ► Hybridization efficiency was 20% for 105-meric PCR product. ► Electrochemical PCR analysis was achieved using ferrocenylnaphthalene diimide. ► This system applied to aberrant methylation detection for the fragment of CDH4 gene. ► This detection can be achieved over 0.5ngμL−1 sample DNA.Hybridization behavior of 24-meric and 105-meric single stranded DNAs derived from CDH4 gene related to cadherin cell-adhesive protein was tested with 24-meric DNA probe in a ferrocenylnaphthalene diimide (FND)-based hybridization assay. Hybridization efficiency in this system was also clarified using chronocoulometric (CC) measurement with Hexaammineruthenium (III) probe (RuHx). This is first example to calculate hybridization efficiency of PCR product with a DNA probe immobilized on the electrode. Although hybridization efficiency was really small for the PCR product as expected (20% for 105-meric PCR product), PCR products carrying aberrant methylation were discriminated from the wild one due to the electrochemical signal of FND. It was possible since FND possessed high preference for double stranded DNA, especially on the electrode. When applied to aberrant methylation detection for the fragment of CDH4 gene, this system can discriminate over 0.5ngμL−1 sample DNA, which is superior to bisulfite sequencing or MSP and COBRA assays.
Keywords: Ferrocenylnaphthalene diimide; Electrochemical gene detection; Aberrant methylation detection; Epigenetics; Hybridization efficiency
Multi-channel purge and trap system coupled with ion chromatography for the determination of alkylamines in cosmetics by Zhixiong Zhong; Gongke Li; Zhibin Luo; Binghui Zhu (pp. 49-56).
Display Omitted► A multi-channel purge and trap system was developed for detecting alkylamines. ► Analytes in cosmetics were detected by ion chromatography. ► Matrix interferences were eliminated effectively. ► Ten channels integration enhanced sample treatment. ► Miniaturization of the steam distillation improved the sensitivity.A new multi-channel purge and trap system coupled with ion chromatography for the determination of six alkylamines in cosmetics was developed. The proposed method, based on purge and trap of the volatile alkylamines, involved in a miniaturization and multi-channel integration of classical steam distillation and a simple approach for routine labs. The procedure was rapidly achieved within 10min and the matrix interferences could be effectively eliminated. Sample pretreatment frequency was higher than 40h−1. The linear ranges were 0.1–15mgL−1 and the detection limits varied from 0.023 to 0.038mgL−1. This method was successfully utilized to determine the amounts of alkylamines in cosmetics with recoveries ranging from 80.3 to 105.5% and the relative standard deviations (RSDs) ranging from 0.78 to 7.5%. It was proved to be accurate, time-saving, and suitable for the determination of large numbers of cosmetics in a short time.
Keywords: Multi-channel purge and trap; Ion chromatography; Alkylamine; Cosmetics
Development of a chromatographic low pressure flow injection system: Application to the analysis of methylxanthines in coffee by João Rodrigo Santos; António O.S.S. Rangel (pp. 57-63).
Display Omitted► Coupling of monolithic columns into traditional low-pressure FIA systems. ► Potential selectivity and increased versatility over low pressure FIA system. ► Flow system presenting lower cost of analysis if compared to HPLC.In this work, the coupling of a commercial monolithic column to a traditional low pressure FIA system is proposed for the analysis of theobromine, theophylline and caffeine in coffee brewed samples using UV detection.The parameters mobile phase composition, flow rate and loop volume were evaluated and discussed considering the various chromatographic parameters in order to enable resolution of the methylxanthines studied within the coffee brewed sample matrix. The analyses of methylxanthines in coffee brewed samples by the proposed methodology were in good agreement with those obtained by the reference procedure based on HPLC. Relative errors were below 6% for all samples analyzed. Detection limits in the selected experimental conditions were within 10−6M range for theobromine and theophylline, and 10−5M for caffeine. The determination rate of the three methylxanthines for coffee brewed samples was ca of 10h−1.The main advantage of the proposed flow system was the possibility to perform chromatographic separations in low pressure flow systems. This substantial improvement was achieved due to the compatibility of monolithic columns within the flow injection system surpassing in this way one of the main handicaps of traditional flow analysis systems. Additional features of the strategy presented were low cost, efficiency, high versatility and low reagent consumption comparing to HPLC methodologies usually followed in the case study herein presented.
Keywords: Low pressure chromatography; Flow injection; Coffee; Methylxanthines; UV spectrophotometry
Ultrahigh performance liquid chromatography–triple quadrupole mass spectrometry inhibitors fishing assay: A novel method for simultaneously screening of xanthine oxidase inhibitor and superoxide anion scavenger in a single analysis by Shu Liu; Junpeng Xing; Zhong Zheng; Fengrui Song; Zhiqiang Liu; Shuying Liu (pp. 64-70).
It is a novel method which combines screening of superoxide anion scavenger and xanthine oxidase inhibitor in a single analysis by adding WST-1 to the enzymatic reaction. This method can accurately quantify the amount of analytes by using multiple reaction monitoring (MRM) function which is through monitoring the ratio of mass and charge ( m/ z) of parent ions and diagnostic fragment ions, therefore, it can eliminate the false positive and false negative results.Display Omitted► A novel method to screen superoxide anion scavenger and xanthine oxidase inhibitor. ► This method can be used to detect and quantify superoxide anion. ► It is a fast, accurate and robust method. ► It can eliminate false positive and negative results.Xanthine oxidase (XOD) inhibitors and superoxide anion scavengers play an important role in the treatment of gout and the inhibition of many diseases related to superoxide anion. The respective quantitation of uric acid and superoxide anion by traditional spectroscopic methods is routine in XOD inhibitors and superoxide anion scavengers screening at laboratories worldwide. In the present study, we established an ultrahigh performance liquid chromatography and triple quadrupole mass spectrometry (UHPLC–TQ-MS) method of higher accuracy and speed that combines screening of superoxide anion scavenger and XOD inhibitor in a single analysis by adding WST-1 (2-(4-iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium sodium salt) to the enzymatic reaction. We applied the established method to determine the XOD inhibitory activities and superoxide scavenging activities of some herbal extracts and compounds from natural products, which could be classified into six groups based on the results of the assay. Our innovative protocol is fast, accurate and robust. Moreover, it can eliminate false positive and false negative results which may occur in the traditional spectroscopic methods.
Keywords: Xanthine oxidase; Inhibitor; Superoxide scavenger; Ultrahigh performance liquid chromatography; Triple quadrupole mass spectrometry
Optimization of solid-phase extraction and liquid chromatography–tandem mass spectrometry for the determination of domoic acid in seawater, phytoplankton, and mammalian fluids and tissues by Zhihong Wang; Jennifer Maucher-Fuquay; Spencer E. Fire; Christina M. Mikulski; Bennie Haynes; Gregory J. Doucette; John S. Ramsdell (pp. 71-79).
Display Omitted► Reversed-phase solid-phase extraction (SPE) was applied for domoic acid extraction and clean-up for LC–MS quantitation. ► An SPE cartridge instead of disk format was used to avoid DA loss during seawater sample loading. ► 20-Fold DA pre-concentration in seawater with/without phytoplankton was achieved after SPE method improvement. ► The SPE method for seawater was modified and extended to mammalian fluids and tissues for LC–MS analysis.We previously reported a solid-phase extraction (SPE) method for determination of the neurotoxin domoic acid (DA) in both seawater and phytoplankton by liquid chromatography–tandem mass spectrometry (LC–MS/MS) with the purpose of sample desalting without DA pre-concentration. In the present study, we optimized the SPE procedure with seawater and phytoplankton samples directly acidified with aqueous formic acid without addition of organic solvents, which allowed sample desalting and also 20-fold pre-concentration of DA in seawater and phytoplankton samples. In order to reduce MS contamination, a diverter valve was installed between LC and MS to send the LC eluant to waste, except for the 6-min elution window bracketing the DA retention time, which was sent to the MS. Reduction of the MS turbo gas temperature also helped to maintain the long-term stability of MS signal. Recoveries exceeded 90% for the DA-negative seawater and the DA-positive cultured phytoplankton samples spiked with DA. The SPE method for DA extraction and sample clean-up in seawater was extended to mammalian fluids and tissues with modification in order to accommodate the fluid samples with limited available volumes and the tissue extracts in aqueous methanol. Recoveries of DA from DA-exposed laboratory mammalian samples (amniotic fluid, cerebrospinal fluid, plasma, placenta, and brain) were above 85%. Recoveries of DA from samples (urine, feces, intestinal contents, and gastric contents) collected from field stranded marine mammals showed large variations and were affected by the sample status. The optimized SPE–LC–MS method allows determination of DA at trace levels (low pgmL−1) in seawater with/without the presence of phytoplankton. The application of SPE clean-up to mammalian fluids and tissue extracts greatly reduced the LC column degradation and MS contamination, which allowed routine screening of marine mammalian samples for confirmation of DA exposure and determination of fluid and tissue DA concentrations in experimental laboratory animals.
Keywords: Domoic acid; Seawater; Phytoplankton; Mammalian fluids and tissues; Solid-phase extraction; Liquid chromatography–mass spectrometry
A novel dichromate-sensitive fluorescent nano-chemosensor using new functionalized SBA-15 by Morteza Hosseini; Vinod Kumar Gupta; Mohammad Reza Ganjali; Zahra Rafiei-Sarmazdeh; Farnoush Faridbod; Hassan Goldooz; Ali Reza Badiei; Parviz Norouzi (pp. 80-85).
Display Omitted► A novel fluorescence nano-chemosensor for Cr2O72− anion has been developed. ► Channels of modified SBA-15 was modified by fluorescent aluminum complex of 8-hydroxyquinoline. ► Observed remarkable fluorescence of SBA-SPS-AlQ x quenches in presence of Cr2O72−. ► Linear detecting range of fluorescent nano-chemosensor for Cr2O72− was 0.16–2.9μM. ► Lowest limit of detection was also found to be 0.2ngmL−1 in aqueous solutions.A novel fluorescence nano-chemosensor for Cr2O72− anion has been developed by assembly of fluorescent aluminum complex of 8-hydroxyquinoline (AlQ x) within the channels of modified SBA-15. SBA-SPS-AlQ x shows a fluorescence emission at 486nm. The observed remarkable fluorescence of SBA-SPS-AlQ x quenches in presence of Cr2O72− anion. The results showed that this fluorescent nano-material can be a useful chemo-sensor for determination of dichromate anions in aqueous solutions. The linear detecting range of fluorescent nano-chemosensor for Cr2O72− anion was 0.16–2.9μmolL−1. The lowest limit of detection (LDL) was also found to be 0.2ngmL−1 in aqueous solutions. SBA-SPS-AlQ x showed selectively and sensitively fluorescent quenching response toward Cr2O72− ion in comparison with I3−, NO3−, CN−, CO32−, Br−, Cl−, F−, H2PO4− and SO42− ions, which was because of the higher stability of its inorganic complex with dichromate ion.
Keywords: Dichromate; Nano-chemosensor; Fluorescence; SBA-15
Electrochemiluminescence biosensor for the assay of small molecule and protein based on bifunctional aptamer and chemiluminescent functionalized gold nanoparticles by Ying Chai; Dayong Tian; Hua Cui (pp. 86-92).
Display Omitted► A novel ECL biosensor based on bifunctional aptamer and ABEI-AuNPs. ► A good prospect for multi-analyte assay of small molecule and protein in biological sample. ► The sensitivity of the sensor is superior to most available aptasensors for adenosine and thrombin. ► The bifunctional aptamer was for the first time applied to ECL biosensor.An electrochemiluminescence (ECL) biosensor for simultaneous detection of adenosine and thrombin in one sample based on bifunctional aptamer and N-(aminobutyl)- N-(ethylisoluminol) functionalized gold nanoparticles (ABEI-AuNPs) was developed. A streptavidin coated gold nanoparticles modified electrode was utilized to immobilize biotinylated bifunctional aptamer (ATA), which consisted of adenosine and thrombin aptamer. The ATA performed as recognition element of capture probe. For adenosine detection, ABEI-AuNPs labeled hybridization probe with a partial complementary sequence of ATA reacted with ATA, leading to a strong ECL response of N-(aminobutyl)- N-(ethylisoluminol) enriched on ABEI-AuNPs. After recognition of adenosine, the hybridization probe was displaced by adenosine and ECL signal declined. The decrease of ECL signal was in proportion to the concentration of adenosine over the range of 5.0×10−12–5.0×10−9M with a detection limit of 2.2×10−12M. For thrombin detection, thrombin was assembled on ATA modified electrode via aptamer–target recognition, another aptamer of thrombin tagged with ABEI-AuNPs was bounded to another reactive site of thrombin, producing ECL signals. The ECL intensity was linearly with the concentration of thrombin from 5×10−14M to 5×10−10M with a detection limit of 1.2×10−14M. In the ECL biosensor, adenosine and thrombin can be detected when they coexisted in one sample and a multi-analytes assay was established. The sensitivity of the present biosensor is superior to most available aptasensors for adenosine and thrombin. The biosensor also showed good selectivity towards the targets. Being challenged in real plasma sample, the biosensor was confirmed to be a good prospect for multi-analytes assay of small molecules and proteins in biological samples.
Keywords: Electrochemiluminescence; N; -(Aminobutyl)-; N; -(ethylisoluminol) functionalized gold nanoparticles; Bifunctional aptamer; Adenosine; Thrombin; Biosensor
Electrochemical genosensor array for the simultaneous detection of multiple high-risk human papillomavirus sequences in clinical samples by Laia Civit; Alex Fragoso; Sebastian Hölters; Matthias Dürst; Ciara K. O'Sullivan (pp. 93-98).
Display Omitted► High-risk human papillomavirus is detected in virtually all-invasive cervical cancers. ► Electrochemical genosensor for simultaneous detection of multiple high-risk HPV applied to cervical scrape samples. ► Excellent correlation with HPV genotyping carried out within a hospital laboratory.An electrochemical genosensor array for the simultaneous detection of three high-risk human papillomavirus (HPV) DNA sequences, HPV16, 18 and 45, exhibiting high sensitivity and selectivity is presented. The electrodes of a 4×4 array were modified via co-immobilization of a 1:100 (mol/mol) mixture of a thiolated probe and an oligoethyleneglycol-terminated bipodal thiol. Detection of synthetic and PCR products was carried out in a sandwich type format, with the target hybridized between a surface immobilized probe and a horseradish peroxidase-labelled secondary reporter probe. The detection limits obtained in the detection of each individual target were in the pM range, allowing the application of this sensor for the detection of samples obtained from PCR amplification of cervical scrape samples. The results obtained exhibited an excellent correlation with the HPV genotyping carried out within a hospital laboratory. Multiplexing and cross-reactivity studies demonstrated high selectivity over potential interfering sequences, facilitating application of the developed platform for the high-throughput screening of multiple high-risk DNA sequences.
Keywords: Multiplexing; Human papillomavirus; DNA detection; Amperometric detection; Clinical diagnostics
Seed-mediated synthesis of copper nanoparticles on carbon nanotubes and their application in nonenzymatic glucose biosensors by Li-Min Lu; Xiao-Bing Zhang; Guo-Li Shen; Ru-Qin Yu (pp. 99-104).
Display Omitted► Seed-mediated method was introduced to prepare of the Cu nanoparticles (CuNPs). ► The CuNPs modified electrode shows high electrocatalytic ability to glucose oxidation in alkaline solution. ► The CuNPs modified electrode has been used to construct a novel nonenzymatic glucose biosensor.In this paper, for the first time, Cu nanoparticles (CuNPs) were prepared by seed-mediated growth method with Au nanoparticles (AuNPs) playing the role of seeds. Carbon nanotubes (CNTs) and AuNPs were first dropped on the surface of glassy carbon (GC) electrode, and then the electrode was immersed into growth solution that contained CuSO4 and hydrazine. CuNPs were successfully grown on the surface of the CNTs. The modified electrode showed a very high electrochemical activity for electrocatalytic oxidation of glucose in alkaline medium, which was utilized as the basis of the fabrication of a nonenzymatic biosensor for electrochemical detection of glucose. The biosensor can be applied to the quantification of glucose with a linear range covering from 1.0×10−7 to 5×10−3M and a low detection limit of 3×10−8M. Furthermore, the experiment results also showed that the biosensor exhibited good reproducibility and long-term stability, as well as high selectivity with no interference from other oxidable species.
Keywords: Seed-mediated growth; Copper nanoparticles; Carbon nanotubes; Biosensor; Glucose; Electrocatalytic oxidation
Generation of anti-azoxystrobin monoclonal antibodies from regioisomeric haptens functionalized at selected sites and development of indirect competitive immunoassays by Javier Parra; Josep V. Mercader; Consuelo Agulló; Antonio Abad-Somovilla; Antonio Abad-Fuentes (pp. 105-112).
Display Omitted► Four azoxystrobin regioisomeric haptens were used to immunize mice. ► A collection of specific monoclonal antibodies was generated. ► The developed competitive immunoassay had a LOD of 17ngL−1 for azoxystrobin standards. ► The optimized assay was validated with fortified and real food samples.Azoxystrobin is a modern strobilurin fungicide used around the world to combat prime diseases affecting highly valuable crops. Accordingly, residues of this chemical are frequently found in food, even though mostly under maximum tolerated levels. We herein describe the development of an indirect competitive immunoassay for the determination of azoxystrobin residues. A panel of monoclonal antibodies displaying subnanomolar affinity to azoxystrobin was generated using, as immunizing haptens in mice, four functionalized derivatives carrying the same spacer arm located at different rationally chosen positions. This collection of antibodies was thoroughly characterized with homologous and heterologous antigens, and the immunoassay consisting of monoclonal antibody AZo6#49 and the coating conjugate OVA–AZb6, which displayed an IC50 value of 0.102μgL−1 and a LOD of 0.017μgL−1, was eventually optimized. The response to different pH and ionic strength conditions of the specific assay was studied using a biparametric approach. In addition, the influence of Tween 20 and organic solvents over the assay parameters was also evaluated. After optimization, the developed immunochemical assay was applied to the analysis of azoxystrobin in spiked juices of relevant fruits and vegetables, showing excellent recoveries between 2 and 500μgL−1.
Keywords: Abbreviations; AZ; azoxystrobin; BSA; bovine serum albumin; CR; cross-reactivity; DMEM; Dulbecco's modified Eagle's medium; ELISA; enzyme-linked immunosorbent assay; FBS; fetal bovine serum; HAT; hipoxanthine–aminopterine–thimidine; HFCS; hybridoma fusion and cloning supplement; HT; hipoxanthine–thimidine; i-cELISA; indirect competitive ELISA; LOD; limit of detection; LOQ; limit of quantification; mAb; monoclonal antibody; MRL; maximum residue limit; OVA; ovalbumin; PBS; phosphate-buffered saline; PBST; phosphate-buffered saline with Tween 20; RAM–HRP; polyclonal rabbit anti-mouse immunoglobulin peroxidase conjugateCompetitive ELISA; Site heterology; Landsteiner's principle; Fungicide; Strobilurins; Food safety
Mixed hemimicelles solid-phase extraction of chlorophenols in environmental water samples with 1-hexadecyl-3-methylimidazolium bromide-coated Fe3O4 magnetic nanoparticles with high-performance liquid chromatographic analysis by Qin Cheng; Fei Qu; Nian Bing Li; Hong Qun Luo (pp. 113-119).
Display Omitted► C16mimBr-coated Fe3O4 magnetic nanoparticles acted as an adsorbent of mixed hemimicelles SPE. ► This SPE method was effective for concentrating chlorophenols prior to HPLC analysis. ► This approach was applied to determine the two chlorophenols in real environmental water samples.In this paper, 1-hexadecyl-3-methylimidazolium bromide (C16mimBr)-coated Fe3O4 magnetic nanoparticles (NPs) as an adsorbent of mixed hemimicelles solid-phase extraction was investigated for the preconcentration of two chlorophenols (CPs) in environmental water samples prior to HPLC with UV detection at 285nm. The high surface area and excellent adsorption capacity of the Fe3O4 NPs after modification with C16mimBr were utilized adequately in the SPE process. By the rapid isolation of Fe3O4 NPs through placing a strong magnet on the bottom of beaker, the time-consuming preconcentration process of loading large volume sample in conventional SPE method with a column can be avoided. A comprehensive study of the adsorption conditions such as the zeta-potential of Fe3O4 NPs, added amounts of C16mimBr, pH value, standing time and maximal extraction volume were also presented. Under optimized conditions, two analytes of 2,4-dichlorophenol (2,4-DCP) and 2,4,6-trichlorophenol (2,4,6-TCP) were quantitatively determined. The method was then used to determine the two CPs in real environmental water samples. The accuracy of method was evaluated by recovery measurements on spiked samples. Good recovery results (74–90%) were achieved. It is important to note that satisfactory preconcentration factors and extraction recoveries for the two CPs were obtained with only a small amount of Fe3O4 NPs (40mg) and C16mimBr (24mg).
Keywords: Chlorophenols; Fe; 3; O; 4; magnetic nanoparticles; Ionic liquid; Solid-phase extraction; Mixed hemimicelles