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Fast screening for anabolic steroids in whole urine is achieved by combining reactive desorption electrospray ionization (reactive DESI) and tandem mass spectrometry. Spray solutions containing hydroxylamine allow heterogeneous reactions of hydroxylamine with the carbonyl group of the steroids during the ionization process. Seven steroids, including a glycosteroid, were examined. The ion/molecule reaction adduct and the oxime formed via its dehydration were observed using reactive DESI; the protonated and sodiated forms of the ionized steroid were also observed both in reactive DESI and in DESI performed without the added hydroxylamine reagent. Paper, glass, and polytetrafluoroethylene were tested as sample substrates, but the glycosteroid was ionized intact without hydrolysis only from polytetrafluoroethylene. Limits of detection for the pure compounds were less than 1 ng, dynamic ranges were typically 2 orders of magnitude, and analysis times were just a few seconds. Concentration levels of ketosteroids in raw urine relevant to screening for sports doping (approximately 20 ng/mL) can be reached using a simple solid-phase microextraction (SPME) preconcentration step. Reactive DESI provided significant improvements in ionization efficiency of these steroids in raw undiluted urine as compared to conventional DESI; suppression effects due to the sample matrix were minimal and the urine matrix had no deleterious effect on steroid detection limits. Tandem mass spectrometry provided confirmation of analyte identification in this rapid screening process. [ABSTRACT FROM AUTHOR]

Current detection methods for paper-based analytical devices (PADs) rely on spectroscopic and electrochemical properties, which place special requirements on the analyte or need analyte labeling. Here, ion-transmission mass spectrometry (MS) was proposed for coupling with PADs to enable rapid in situ MS analysis of the sample on paper. The sample was analyzed directly on paper via analyte ionization by ions transmitted through the paper, generated by a low-temperature plasma probe. Prior to MS analysis, the sample can be separated by paper electrophoresis or by paper chromatography, among a variety of other features offered by PADs. The versatility of this technique was demonstrated by MS analysis of a paper microarray, a nurture of amino acids, and whole blood doped with drugs on PADs. [ABSTRACT FROM AUTHOR]

We had developed pulsed direct current electrospray ionization mass spectrometry (pulsed-dc-ESI-MS) for systematically profiling and determining components in small volume sample. Pulsed-dc-ESI utilized constant high voltage to induce the generation of single polarity pulsed electrospray remotely. This method had significantly boosted the sample economy, so as to obtain several minutes MS signal duration from merely picoliter volume sample. The elongated MS signal duration enable us to collect abundant MS2 information on interested components in a small volume sample for systematical analysis. This method had been successfully applied for single cell metabolomics analysis. We had obtained 2-D profile of metabolites (including exact mass and MS2 data) from single plant and mammalian cell, concerning 1034 components and 656 components for Allium cepa and HeLa cells, respectively. Further identification had found 162 compounds and 28 different modification groups of 141 saccharides in a single Allium cepa cell, indicating pulsed-dc-ESI a powerful tool for small volume sample systematical analysis. [ABSTRACT FROM AUTHOR]

Sensitive detection of biomolecules in small-volume samples by mass spectrometry is, in many cases, challenging because of the use of buffers to maintain the biological activities of proteins and cells. Here, we report a highly effective desalting method for picoliter samples. It was based on the spontaneous separation of biomolecules from salts during crystallization of the salts. After desalting, the biomolecules were deposited in the tip of the quartz pipet because of the evaporation of the solvent. Subsequent detection of the separated biomolecules was achieved using solvent assisted electric field induced desorption/ionization (SAEFIDI) coupled with mass spectrometry. It allowed for direct desorption/ionization of the biomolecules in situ from the tip of the pipet. The organic component in the assistant solvent inhibited the desorption/ionization of salts, thus assured successful detection of biomolecules. Proteins and peptides down to 50 amol were successfully detected using our method even if there were 3 x 105 folds more amount of salts in the sample. The concentration and ion species of the salts had little influence on the detection results. [ABSTRACT FROM AUTHOR]

The discrimination of the type of cancer cells remains challenging due to the subtle differences in their expression of membrane receptors. In this work, we developed a multicolor cell imaging method for distinguishing the type of cancer cells with fluorophore-tagged aptamers. We found that the interaction between aptamers and cancer cells was affected by both of the sequence of aptamers and the labeled dyes. As the co-ownership of biomarkers for different cancer cell lines, the fluorophore-tagged aptamers interacted with different cancer cell lines in different degree, resulting in a distinct color to discriminate the type of cancer cells at single cell level. Taking advantage of the cross-reactive ability of the fluorophore-tagged aptamers, we could not only distinguish the cancerous cells quickly from large quantities of noncancerous cells, but also identify the type of the cancerous cells. This work has potential application for cancer diagnostic and therapy in the future. [ABSTRACT FROM AUTHOR]

With the inspiration of an ancient Chinese poison test approach, we report a rapid hydrogen sulfide detection strategy in specific areas of live cells using silver needles with good spatial resolution of 2 × 2 μm². Besides the accurate-localization ability, this reflection-based strategy also has attractive merits of convenience and robust response when free pretreatment and short detection time are concerned. The success of endogenous H2S level evaluation in cellular cytoplasm and nuclear of human A549 cells promises the application potential of our strategy in scientific research and medical diagnosis. [ABSTRACT FROM AUTHOR]

Molecular analysis at cellular and subcellular levels, whether on selected molecules or at the metabolomics scale, is still a challenge now. Here we propose a method based on probe ESI mass spectrometry (PESI-MS) for single cell analysis. Detection of metabolites at cellular and subcellular levels was successfully achieved. In our work, tungsten probes with a tip diameter of about 1 μm were directly inserted into live cells to enrich metabolites. Then the enriched metabolites were directly desorbed/ionized from the tip of the probe for mass spectrometry (MS) detection. The direct desorption/ionization of the enriched metabolites from the tip of the probe greatly improved the sensitivity by a factor of about 30 fold compared to those methods that eluted the enriched analytes into a liquid phase for subsequent MS detection. We applied the PESI-MS to the detection of metabolites in single Allium cepa cells. Different kinds of metabolites, including 6 fructans, 4 lipids, and 8 flavone derivatives in single cells, have been successfully detected. Significant metabolite diversity was observed among different cells types of A. cepa bulb and different subcellular compartments of the same cell. We found that the inner epidermal cells had about 20 fold more fructans than the outer epidermal cells, while the outer epidermal cells had more lipids. We expected that PESI-MS might be a candidate in the future studies of single cell "omics". [ABSTRACT FROM AUTHOR]

A multiplex DNA assay based on nanoparticle (NP) tags detection utilizing single particle mode inductively coupled plasma mass spectrometry (SP-ICP-MS) as ultrasensitive readout has been demonstrated in the article. Three DNA targets associated with clinical diseases (HIV, HAV, and HBV) down to 1 pM were detected by DNA probes labeled with AuNPs, AgNPs, and PtNPs via DNA sandwich assay. Single nucleotide polymorphisms in genes can also be effectively discriminated. Since our method is unaffected by the sample matrix, it is well-suited for diagnostic applications. Moreover, with the high sensitivity of SP-ICP-MS and the variety of NPs detectable by SP-ICP-MS, high-throughput DNA assay could be achieved without signal amplification or chain reaction amplification. [ABSTRACT FROM AUTHOR]

We developed a colorimetric sensor array with reported protein aptamers as nonspecific receptors. We found that different target proteins could make the aptamer-protected gold nanoparticles (AuNPs) exhibit different aggregation behaviors in the presence of a high concentration salt and cause various color change. On the basis of this phenomenon, we applied a series of reported protein aptamers as a receptor array obtaining a distinct response pattern to each target protein. Seven proteins have been well distinguished with the naked eye at the 50 nM level. Cancerous human cells have also been discriminated from noncancerous cells. This method is simple, label-free, and sensitive. It will broaden the application filed of plasmonic nanoparticle-based sensors and give a new direction of developing sensitive array sensing systems. [ABSTRACT FROM AUTHOR]

Fluorescent gold nanoparticle (GNP) is an easily synthesized and biocompatible optical platform for sensing and imaging with tunable near-infrared (NTR) emission. However, the relatively low fluorescence (FL) quantum yield limits the further improvement of sensitivity and application. Here, we find that, on plasmonic substrates, the FL intensity of protein-directed synthesized GNPs can be enhanced significantly (~20-fold). Moreover, protein analytes can interact with GNPs and influence the enhanced fluorescence process so that we can obtain distinct FL image patterns. Then, using the array-based sensing strategy, protein discrimination can be achieved. In our present experiment, five GNPs were used as sensing elements and 10 kinds of proteins at three concentrations (0.2, 03, and 1 μM) were successfully identified. This array-based sensing strategy using enhanced-fluorescence from GNPs is highly sensitive and differentiable, expanding the application field of GNPs. [ABSTRACT FROM AUTHOR]

The method for the localization of bioactive molecules in plants is highly needed since it provides a fundamental prerequisite for understanding their physiological and ecological functions. Here, we propose a simple method termed in vivo nanoelectrospray for the localization of bioactive molecules in plants without sample preparation. A capillary is partly inserted into the plant to sample liquid from a highly located region, and then, a high voltage is applied to the plant to generate an electrospray from the capillary tip for mass spectrometry analysis. Using this method, bioactive molecules such as saccharides, glycoalkaloids, flavonoids, organic acids, and glucosinolates (GLs) are detected in the target regions of living plants or fresh fruits. Original information for endogenous chemicals including liable molecules in plant can be obtained. A sketchy three-dimensional distribution of glycoalkaloids in a cherry tomato has been obtained. The present work provides a powerful tool for the study of bioactive molecules in a living plant by mass spectrometry. [ABSTRACT FROM AUTHOR]

A novel ionization device for controlling the charge states of peptides based on an inductive elecrospray ionization technique was developed. This ion source keeps the major capabilities of electrospray ionization (ESI) which is compatible with liquid separation techniques (such as liquid chromatography (LC) and capillary electrophoresis (CE)) and can be potentially used to control the charge states of peptides accurately by simply varying the AC voltage applied. In comparison with conventional ESI, inductive ESI successfully simplifies the mass spectrum by reducing the charge states of peptide to a singly charged one, as well as eliminating the adductions. [ABSTRACT FROM AUTHOR]

The fluorescence of metal nanoclusters provides an amusing optic feature to be applied in various fields. However, rational design of dual functional fluorescent metal nanoclusters directed by active enzyme with targeted application remains little explored. In this work, we report a new strategy to construct enzyme functionalized fluorescent gold nanoclusters via a biomineralization process for the detection of hydrogen peroxide. Horseradish peroxidase (HRP) was used as a model functional template to direct the synthesis of fluorescent gold nanoclusters (Au NCs) at physiological conditions to form HRP—Au NCs bioconjugates. We found that the fluorescence of HRP-Au NCs can be quenched quantitatively by adding H2O2 indicating that HRP enzyme remains active and enables catalytic reaction of HRP-Au NCs and H2O2. Upon the addition of H2O2 under optimal conditions, the fluorescence intensity quenched linearly over the range of 100 nM to 100 μM with high sensitivity (LOD = 30 nM, S/N = 3). This study would be potentially extended to other functional proteins to generate dual functional nanoclusters and applied to real time monitoring of biologically important targets in living cells. [ABSTRACT FROM AUTHOR]

The development of material science increasingly calls for rapid characterization methods with low limits of detection and high spatial resolution. Here we report a depth profile analysis method for thin layer coatings by combining low temperature plasma (LTP) probe with inductively coupled plasma mass speclrometiy (ICP-MS). The LTP probe with diameter of several tens of micrometers served as a tool for mass removal, which is generated by the discharge in a quartz capillaiy at ambient condition. The sample material is ablated by the LTP probe and converted into an aerosol, and transported by a carrier gas flow to the ICP-MS, where the decomposed and ionized aerosol particles are analyzed with high sensitivity. Scanning electron microscope (SEM) micrographs reveal that the trace after ablation by the LTP probe is a hole with a diameter less than 10 pm. A lateral resolution of approximately 200 pm has been achieved by analyzing an electron component with interval metal stripes. Depth profiling of a 100 nm single layer sample and a multiple layer sample (100 nm Al/250 nm SiOillOO nm Au150 nm Cr) on a silicon substrate have been successfully performed at ambient condition. The present method offers unique advantages in terms of high spatial resolution, fast analysis speed and ease of implementation. It might be considered a complementary technique to existing depth profiling methods such as GDMS/OES, AES, and SIMS. In addition, the simple-to fabricate LTP probe is easily coupled to various other elemental analysis tools for thin layer or direct solid sample analysis in micro area. [ABSTRACT FROM AUTHOR]

High-throughput screening of catalysts could dramatically improve performance and reduce costs in the discovery and study of various catalysts. Here we report a cataluminescence-based array imaging as a high-throughput screening technique in the combinatorial discovery of active catalysts for CO oxidation. This strategy is based on the fact that the CO oxidation generates cataluminescence emission on the surface of nanomaterials, whose intensity is correlated to the activity of the catalyst. To demonstrate the feasibility of the cataluminescence-based array imaging for high-throughput screening of catalysts, different nanosized metal catalysts supported on TiO2 nanoparticles were prepared. These catalysts include monometallic Au, Pt, and the bimetallic Au-Pt heteroaggregate catalysts, at total metal loadings of 0.5%, 1.0%, and 2.5%, and with atomic ratios of 1:1, 1:2, and 2:1 (Au/Pt). A 4 × 4 array was integrated by depositing these nanosized catalysts onto the ceramic chip, and the brightness of each spot in the image was recorded. The catalytic activities of those catalysts for the CO oxidation were evaluated parallelly by both the cataluininescence imaging and the gas chromatography method. The correlation coefficient is 0.9 14 for the two techniques, indicating that the cataluminescence imaging technique can be applied for the evaluation of the catalytic activities. Moreover, fast evaluation of multiple catalysts at a series of working temperature can be achieved by this cataluininescene-based array imaging. With the development of nanotechnology as well as the catalyst industry, the cataluminescence-based array imaging will address its importance in the high-throughput screening of catalysts. [ABSTRACT FROM AUTHOR]

A cross-reactive chemiluminescence (CL) sensor array based on catalytic nanomaterials was constructed for the discrimination and identification of flavors in cigarettes. A total of 21 nanomaterials, including metal oxides, metal oxides deposited on carbon nanotubes (CNTs), gold nanoparticles deposited on metal oxides, and carbonate, have been carefully selected as sensing elements of the array. Each flavor gives its unique CL pattern from the array, which is able to be employed for the discrimination and identification of flavors. Hierarchical cluster analysis (HCA) and linear discriminant analysis (LDA) were used to analyze the patterns. The obtained CL patterns are temperature dependent, thus additional discrimination power could be provided by changing the working temperature of the array. Quantification of the flavors has been performed according to the emission intensity on the specific sensing element. The linear ranges of the sensor array for the flavors are in the range of 20-2000 ppmv with the limits of detection below 10 ppmv, which vary with the kinds of flavors. Six brands of cigarettes have been discriminated by their CL patterns obtained with the present sensor array. The robust and reversible response of this array, combined with its simple instrumentation, indicates the promise of this array for real world application. [ABSTRACT FROM AUTHOR]

A low-temperature plasma (LTP) probe has been developed for ambient desorption ionization. An ac electric field is used to induce a dielectric barrier discharge through use of a specially designed electrode configuration. The low-temperature plasma is extracted from the probe where it interacts directly with the sample being analyzed, desorbing and ionizing surface molecules in the ambient environment This allows experiments to be performed without damage to the sample or underlying substrate and, in the case of biological analysis on skin surfaces, without electrical shock or perceptible healing. Positive or negative ions are produced from a wide range of chemical compounds in the pure state and as mixtures in the gaseous, solution, or condensed phases, using He, Ar, N2, or ambient air as the discharge gas. Limited fragmentation occurs, although it is greater in the cases of the molecular than the atomic discharge gases. The effectiveness of the LTP probe has been demonstrated by recording characteristic mass spectra and tandem mass spectra of samples containing hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and 2,4,6-trinitrotoluene (TNT) from poly(tetrafluoroethylene) (PTFE) surfaces where limits of detection are as low as 5 pg. Other performance characteristics, when using a commercial ion trap mass spectrometer, include 3-4 orders of magnitude linear dynamic range in favorable cases. Demonstration applications include direct analysis of cocaine from human skin, determination of active ingredients directly in drug tablets, and analysis of toxic and therapeutic compounds in complex biological samples. Ionization of chemicals directly from bulk aqueous solution has been demonstrated, where limits of detection are as low as 1 ppb. Large surface area sampling and control of fragmentation by a simple adjustment of the electrode configuration during operation are other demonstrated characteristics of the method. [ABSTRACT FROM AUTHOR]

A low-power, atmospheric-pressure microplasma source based on a dielectric barrier discharge (DBD) has been developed for use in atomic emission spectrometry. The small plasma (0.6 mm × 1 mm × 10 mm) is generated within a glass cell by using electrodes that do not contact the plasma. Powered by an inexpensive ozone generator, the discharge ignites spontaneously, can be easily sustained in Ar or He at gas flow rates ranging from 5 to 200 mL min-1, and requires less than 1 W of power. The effect of operating parameters such as plasma gas identity, plasma gas flow rate, and residual water vapor on the DBD source performance has been investigated. The plasma can be operated without removal of residual water vapor, permitting it to be directly coupled with cold vapor generation sample introduction. The spectral background of the source is quite clean in the range from 200 to 260 nm with low continuum and structured components. The DBD source has been applied to the determination of Hg by continuous-flow, cold vapor generation and offers detection limits from 14 (He-DBD) to 43 pg mL-1 (Ar-DBD) without removal of the residual moisture. The use of flow injection with the He-DBD permits measurement of Hg with a 7.2 pg limit of detection, and with repetitive injections having an RSD of <2% for a 10 ng mL-1 standard. [ABSTRACT FROM AUTHOR]

A novel vapor-generation technique is described for mercury determination in aqueous solutions. Without need for a chemical reducing agent, dissolved mercury species are converted to volatile Hg vapor in a solution cathode glow discharge. The generated Hg vapor is then transported to an inductively coupled plasma for determination by atomic emission spectrometry. Mercury vapor is readily generated from a background electrolyte containing 0.1 M HNO3. Vapor generation efficiency was found to be higher by a factor of 2-3 in the presence of low molecular weight organic acids (formic or acetic acids) or alcohols (ethanol). Optimal conditions for discharge-induced vapor generation and reduced interference from concomitant inorganic ions were also identified. However, the presence of chloride ion reduces the efficiency of Hg-vapor generation. In the continuous sample introduction mode, the detection limit was found to be 0.7 μg L-1, and repeatability was 1.2% RSD (n = 11) for a 20 μg L-1 standard. In comparison with other vapor generation methods, it offers several advantages: First, it is applicable to both inorganic and organic Hg determination; organic mercury (thiomersal) can be directly transformed into volatile Hg species without the need for prior oxidation. Second, the vapor-generation efficiency is high; the efficiency (with formic acid as a promoter) is superior to that of conventional SnCl2-HCl reduction. Third, the vapor generation is extremely rapid and therefore is easy to couple with flow injection. The method is sensitive and simple in operation, requires no auxiliary reagents, and serves as a useful alternative to conventional vapor generation for ultratrace Hg determination. [ABSTRACT FROM AUTHOR]

A simple and easy-to-build high-throughput analysis system was constructed. The system consisted of three major components: (1) a multichannel device with 16 parallel capillaries, (2) a desorption electrospray ionization (DESI) source, and (3) a linear ion trap mass spectrometer. When analyses were performed, the multichannel device was moved horizontally on a translation stage controlled by a step motor. Our design expands the functions of DESI, in which the liquid sample in capillary was driven out by the nebulizing gas, ionized, and then transferred to a mass spectrometer. To assess the high-throughput performance of the system, 5 mg/L 1,3-diethyl-1,3-diphenylurea (DDU) solution and 10 mg/L angiotensin 1 solution were alternatively loaded into the reservoirs and capillaries in the multichannel device. Results indicated that analyses of the all the samples in 16 capillaries were completed within 1.6 mm, which means a throughput of 600 samples/h. Reactive DESI experiment was also successfully performed with this system to show the feasibility of online derivatization. The relative standard deviations for a single capillary and five identical capillaries were 7.6 (n = 16) and 12.3%, respectively. Linear relative abundance response was achieved for DDU (r=0.9971). [ABSTRACT FROM AUTHOR]

Inductively coupled plasma mass spectrometry (ICPMS) has been successfully used for the detection of element-tagged biomolecules with the advantage of multielement capability. However, this technique cannot be used for microarray detection due to the necessity to dissolve the elemental tags before introducing them to the plasma source. Here, we report the detection of multiple proteins on each spot of the immuno-microarray by laser ablation ICPMS. α-Fetoprotein IgG (AFP), carcinoembryonic antigen (CEA), and human IgG, as model proteins, have been detected on the basis of sandwich-type immunoreactions on a microarray with Sm3+-labeled AFP antibody, Eu3+-labeled CEA antibody, and Au-labeled goat-anti-human IgG (GAB) as labeled antibodies. The detection limits were 0.20, 0.14, and 0.0 12 ng mL-1 (3σ) with the RSD of 5.7%, 2.6%, and 2.3% at the concentration of 1.0 ng mL-1 for AFP, CEA, and human IgG, respectively. The present detection method permits detecting multiple analytes from each spot of microarray with a spatial resolution at micrometer range, which can alleviate the stress to fabricate high-density arrays. Furthermore, the substrate materials and immobilized proteins do not interfere with the detection. The present technique provides a new strategy for readout of microarray. [ABSTRACT FROM AUTHOR]

This paper describes a novel hydride atomizer based on atmospheric pressure dielectric barrier discharge (DBD) plasma. The plasma was generated with a 3700-V, 20.3-kHz, and 5-W electrical power supply and easily sustained with inert gases (He or Ar) at a flow rate of 250 mL.min-1 after optimization. However, it cannot be sustained with N2. This atomizer offers the advantages of low operation temperature and low power consumption in comparison with the currently used electrothermal quartz atomization operated at 900 °C with a power supply of several hundred watts. To confirm the utility of the proposed atomizer, four arsenic species (As(III), As(V), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA)) were determined by the present atomization technique. A hyphenation of HPLC coupled to hydride generation MS with the optimized DBD atomizer has been successfully used for the speciation of arsenic in order to demonstrate the potential of this atomizer in the present study. The characteristics of the DBD atomizer and the effects of different parameters (discharge gas, gas flow rate, voltage, HCI concentration, KBH4 concentration) are discussed in the paper. Compared with other hydride atomization techniques, the proposed method shows the following features: (1) small size (70 mm x 15 mm x 5 mm), which is preferable for the miniaturization of the total analytical system; (2) low power consumption (⩽ 5W), which indicates the possibility of the development of portable, fieldable analytical instrumentation for in situ detection using battery as power supply; (3) low atomizer temperature (∼70 °C), which is in favor of the compactness of the total instruments; (4) avoidance of residue moisture removal in comparison with the existed GD system, which leads to the facility of the system. The analytical figures of the present technique were evaluated. The detection limits of As(III), As(V), MMA, and DMA obtained with HG-DBD-AAS were 1.0, 11.8, 2.0, and 18.0 μg.L-1, respectively. The accuracy of the system was verified by the determination of arsenic in reference material of orchard leaves SRM 1571. The concentration of As determined by the present method agreed well with the reference values. The speciation of arsenic in the freeze-dried urine SRM 2670 were carried out, and the results obtained were in agreement with the results of HPLC-ICPMS and the reported values by other laboratories. [ABSTRACT FROM AUTHOR]

A novel aerosol chemiluminescent (CL) detector coupling to capillary electrophoresis (CE) for the detection of saccharides is reported. This CL detector is composed of a postcapillary nebulizer and porous alumina as catalyzer in quartz tube. The CL emission could be generated due to the catalyzing oxidization of saccharides on the surface of porous alumina. The saccharides such as sucrose, α-lactose, maltose, raffinose, galactose, xylose, and glucose with only weak UV absorbance can be successfully detected. The linear ranges of those saccharides are from 30-2000 to 50-2000 mg/L; relative standard deviations range from 2.1 to 3.7% (200 mg/L, n = 11). Compared with the traditional UV detector currently used in CE, this novel detector shows the advantage of high sensitivity to the compounds with only weak UV absorption. Thus, it could be an important supplement of CE detectors for UV- lacking compounds. [ABSTRACT FROM AUTHOR]

Proposes a gas-sensing mode based on chemiluminescence generated on the surface of nanosized titanium dioxide (TiO[sub 2]). Detection of chemiluminescence in the nanosized materials; Characteristics of ethanol and acetone vapors passing through the surface of TiO[sub 2]; Removal of carbon deposited on TiO[sub 2] by controlling the temperature.

Describes the study of atomization of nanoparticles using inductively coupled plasma mass spectrometry (ICPMS). Sensitivity of the gold signal to the organic matrix; Correlation between the method and enzyme-linked immunosorbent assay; Advantages of ICPMS-based nonisotopic immunoassay method for the determination of biologic analytes.

A novel method has been proposed to enhance efficiency of cataluminescence reaction by applying a plasma-assisted cataluminescence (PA-CFL) system. The obtained results clearly indicated that the PA-CFL system exhibited substantially higher sensitivity for the detection of benzene, toluene, ethylbenzene, and xylenes (BTEX) on the surface of nanosized ZrO2. There are two distinctive advantages in the PA-CFL system; on one hand, the plasma activates the BTEX molecules for the detection, and on the other hand, the worldng temperature range of the catalytic reaction is lowered with the plasma assistance. A detection limit (LOU = 3σ) of 20 ng mL-1 was achieved for benzene in air samples. Using a graphite electrode in the designed plasma provides an additional opportunity for solid-phase microexfraclion (SPME) sampling of volatile organic compounds (VOCs) on its surface followed by PA-CFL detection. This ability has been investigated for detection of m-xylene in air samples. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the editor discusses various reports within the issue on topics including the scope of analytical chemistry, principles of chemical measurement science, and measurement of chemical compound and other elements.