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The presence of trace contaminants in ultra-pure water (UPW) used in fabrication process can greatly affect the yield and quality of industrial products. In the present study, the electrodialytic enrichment of metal cations as a means of continuously monitoring the UPW quality was studied. A newly designed electrodialytic enrichment device (EED) was used to quantitatively transfer metal ions from samples to dilute nitric acid, which was then directly introduced into an inductively coupled plasma-mass spectrometry (ICP-MS) instrument. This process could be performed without contamination of the sample, and the enrichment factor was solely dependent on the flow rate ratio of the sample and acceptor solutions. The transference of analytes into the acidic solution improved the responsivity of the ICP-MS analysis, especially at low concentrations of less than 1 μg/L. Blank solutions to support the analysis of UPW could be produced using the EED effluent, from which metal ions were quantitatively removed. In addition, calibration curves with concentration ranges of several nanograms per liter were obtained by preparing standards using a dynamic gravimetric method while employing a single bottle and continuous mass monitoring to avoid any contamination from the volumetric flasks. The sensitivities associated with the ICP-MS analysis of a number of trace metal ions were improved by one or two orders of magnitude. The data show that the present EED is able to continuously produce enriched analyte solutions to allow the ongoing monitoring of UPW quality.

Gas- and particle-phase nitrophenols are collected separately and preconcentrated for HPLC analysis. Time variations in concentrations and partitioning into particles of nitrophenols are obtained with a resolution of 2 h.

Phytoplankton dinoflagellate forms colonies between vertical ice crystals during the ice-melting season in Lake Baikal: how the plankton survive the freezing conditions was previously not known. Here we show that the phytoplankton produces large amounts of dimethylsulfoniopropionate (DMSP) known as a marine compound. Lake-water DMSP concentrations in the spring season are comparable with those in the oceans, and colony water in ice exhibits extremely high concentrations. DMSP concentration correlates with plankton density and reaches maximum in mid-April with exhibiting temperature-dependent fluctuations. DMSP is released from plankton cells into water in warm days. DMSP is a characteristic osmolyte of marine algae; our results demonstrate that the freshwater plankton has the DMSP-producing ability, and efficiently uses the limited sulfur resource (only 1/500 of sea sulfate) to survive in freshwater ice. Plankton in Lake Baikal do not need an osmolyte, and our results indicate that DMSP plays a purely cryoprotective role.

A portable chemical analysis system for monitoring ambient carbonyl sulfide (COS) was investigated for the first time. COS is paid attention to from the perspectives of photosynthesis tracer, breath diagnosis marker, and new process-use in the manufacture of semiconductors. Recently, the threshold level value of COS was settled at 5 ppm in volume ratio (ppmv) for workplace safety management. In this work, COS was converted to H2S by a small column packed with alumina catalyzer at 65 °C. Then, the H2S produced was collected in a small channel scrubber to react with fluorescein mercuric acetate (FMA), and the resulting fluorescence quenching was monitored using an LED/photodiode-based miniature detector. The miniature channel scrubber was re-examined to determine its robustness and easy fabrication, and conditions of the catalyzer were optimized. When the FMA concentration used was 1 μM, the limit of detection and dynamic range, which were both proportional to the FMA concentration, were 0.07 and 25 ppbv, respectively. Ambient COS in the background level and even contaminated COS in the nitrogen gas cylinder could be detected. If necessary, H2S was removed selectively by reproducible adsorbent columns. COS concentrations of engine exhaust were measured by the proposed method and by cryo-trap-gas chromatography-flame photometric detection, and the results obtained (0.5–5.9 ppbv) by the two methods agreed well (R2 = 0.945, n = 19). COS in ambient air and exhaust gases was successfully measured without any batchwise pretreatment.

Radioactive metals are applied in biochemistry, medical diagnosis such as positron emission tomography (PET), and cancer therapy. However, the activity of radioisotopes exponentially decreases with time; therefore, rapid and reliable probe preparation methods are strongly recommended. In the present study, electrodialytic radioactive metal ion handling is studied for counter ion conversion and in-line probe synthesis. Presently, counter ion conversion and probe synthesis are achieved by evaporative dryness and solution mixing, respectively. Evaporative dryness is time-consuming and is a possible process that can lead to loss of radioactive metal ions. Mixing of solutions for synthesis makes dilution and undesirable effects of counter ion on the synthesis. An optimized electrodialytic flow device can transfer a radioisotope

Electrodialytic handling of radioactive metal ions such as 64Cu2+ was studied in the present study. Using optimized electrodialytic flow device, the matrix of donor containing 64Cu2+ can be transferred from hydrochloric acid into nitric acid, acetic acid, and citric acid in acceptor. When the ligand was dissolved in acceptor solution, the transferred metal ions from donor were well mixed and formed complex with ligand in-line. The relatively larger flow rate of donor to acceptor can enrich the metal ion in acceptor solution continuously. The present electrodialytic ion handling method can treat ultra-trace radioisotopes rapidly, effectively, and safely in closed system.

In plants, growth–defense tradeoffs are essential for optimizing plant performance and adaptation under stress conditions, such as pathogen attack. Root-knot nematodes (RKNs) cause severe economic losses in many crops worldwide, although little is known about the mechanisms that control plant growth and defense responses during nematode attack. Upon investigation of Arabidopsis thaliana infected with RKN (Meloidogyne incognita), we observed that the atypical transcription factor DP-E2F-like 1 (DEL1) repressed salicylic acid (SA) accumulation in RKN-induced galls. The DEL1-deficient Arabidopsis mutant (del1-1) exhibited excessive SA accumulation in galls and is more resistant to RKN infection. In addition, excessive lignification was observed in galls of del1-1. On the other hand, the root growth of del1-1 is reduced after RKN infection. Taken together, these findings suggest that DEL1 plays an important role in the balance between plant growth and defense responses to RKN infection by controlling SA accumulation and lignification.

Heavy metals in particulate matter (PM) are of great concern, and their effects on the environment and human health depend on their solubilities and species present. In this study, the solubility of As, Se, Sb, V and Cr and their species eluted in water was investigated. As, Se, Sb, and V were present mostly in fine particles, and they were predominantly water-soluble in fine particles ( 2.5 μm). Solubility of Cr was poor even in fine particles. It was found that for fine particles, solubilities of the heavy metals were related to the nitrate and sulfate contents. This suggests that the higher the acidity of the particles, the higher the solubility of the heavy metals. Oxoanions of the five kinds of heavy metals in water extracts of fine particles were determined by inductively coupled plasma mass spectrometry preceded by ion chromatography. The results suggested the presence of atmospheric oxidation during the aerosol transportation. Also, the As(iii)/As(v) (arsenite/arsenate) ratios for the fine particle extracts were related to the transition metal concentrations, which indicated that Fe, Cu, etc. in fine particles affected the As redox equilibrium. It was suggested that the heavy metals exist as complexes with iron hydroxide and dissolved organic matter in addition to the free oxoanions. These investigations were performed for PM samples collected in winter and summer in Kumamoto, west Japan, where the site is strongly exposed to westerly winds from continental East Asia. The obtained results improve our understanding of the behavior of the heavy metals in airborne PM after depositing on a wet environment and biota.

Preparing compounds containing the radioisotope

Short-lived radioactive metals are important tracers in clinical diagnosis. Radioactive metals for clinical use are produced from suitable target metals in cyclotrons. The trace amount of radioactive metal produced is contained in a relatively large amount of target metal. A rapid and effective method is required to isolate the radioactive metal. In the present study, selective complex formation followed by cation-exchange adsorption was performed in a continuous flow-based system. Ethylenediamine

A fast response potentiometric flow-through pH sensor was applied for organic acid determination. The analyte response with the pH sensor was obtained by eluent pH modification following ion exclusion chromatography with HClO4 as an eluent. The response characteristics depend on the adjusted baseline pH. The baseline pH adjustment was successfully done with an ammonia permeation device without solution mixing, which may cause analyte dilution, dispersion, and mixing noise. After pH adjustment, the pH response was universal to the equivalent of introduced analyte acids because the pH response was obtained by the titration of the permeant ammonia by the analytes. The average of limit of detections (S/N = 3) was 0.06 mM for seven target organic acids. Furthermore, the pH response follows the theoretical pH calculation with the concentrations of the eluent, pH modifier, and analyte. Thus, the analyte concentration in the sample can be theoretically calculated from the pH response without calibration by the analyte standard. Predicted concentrations of injected standards were within 5% of the actual standard concentration. Additionally, analysis of real samples was performed and compared with the conventional post-column reaction with a bromothymol blue (BTB) method. The results obtained with the present system (absolute quantification with theoretical calculation) and conventional BTB method agreed within 10% of errors.

An automated device has been developed to measure aqueous dimethyl sulfide (DMSaq), its precursor dimethylsulfoniopropionate (DMSP), and atmospheric gaseous dimethyl sulfide (DMSg). In addition to having a role in the oceanic atmosphere, DMS and DMSP have recently gained substantial interest within the biosciences and are suspected as chemoattractants for predators searching for prey. To provide the spatial resolution relevant for biogeochemical functions, fast and on-site analysis of these compounds is an important technique. The system described measures the dimethyl sulfur compounds by sequential vaporization of DMSaq and DMSP to their gas phase, which is then analyzed by chemiluminescence detection (SVG-CL). The device has five analysis modes (full, DMS, water, gas, and DMSP mode) that can be selected by the user depending on the required analyte or desired sampling rate. Seawater analyses were performed by the developed SVG-CL system and, simultaneously, by an ion molecule reaction-mass spectrometer and a gas chromatograph-flame photometric detector to verify quantitative analysis results. Results obtained by the new method/device agreed well with those by the other methods. Detection limits of the SVG-CL system are 0.02 ppbv and 0.04 nM for DMSg and DMSaq/DMSP, respectively, which are much better than those of the mass spectrometer. The SVG-CL system can be easily installed and operated on a boat. Spatial variability in DMS and DMSP off the coast of Japan were obtained, showing significant changes in the concentrations of the components at the brackish/saline water interface and at the channel between the closed and open seas.

Dimethylsulfide (DMS) is a biogenic volatile organic compound of high interest as it can influence the Earth's climate by contributing to cloud formation in the atmosphere. Although DMS occurs at high concentrations in coral reef ecosystems, the role of permeable coral reef carbonate sediments as a source and sink of DMS to the surrounding seawater is unknown. Here, we report for the first time fluxes of dissolved DMS from permeable coral reef carbonate sediments over a full diel cycle obtained from benthic chamber deployments on the reef flat of Heron Island, southern Great Barrier Reef . Carbonate coral reef sediments were a substantial net diel source of DMS to the water column (mean 85.4 ± 13.2; range 42.3 ± 5.1 to 114 ± 4.7 nmol m −2 h−1 ), with rates similar to saltmarsh sediments. DMS effluxes were higher in the light under advective porewater flow, suggesting that DMS production in carbonate coral reef sediments is associated with photosynthesis by benthic microalgae. However, DMS effluxes decreased with advection at night, suggesting either greater DMS consumption or less DMS production under dark conditions. Similarly, dimethylsulfoniopropionate (DMSP), which is generally considered the main precursor of DMS, was mainly produced during the day. Net and dark methane (CH 4) effluxes negatively correlated with net DMSP and dark DMS fluxes, respectively; suggesting that CH4 production via methanogenesis could be a sink for DMS and DMSP in carbonate coral reef sediments, especially under dark anoxic conditions . On Heron Island the permeable sands were estimated to contribute from about 22% to 44% of the benthic DMS emitted from the reef to the water column, which could represent an important portion of the yearly sea-to-atmosphere DMS fluxes. Permeable carbonate sediments should be considered further as a source of benthic DMS emitted from coral reefs and the broader continental shelf .

The mass development of the phototrophic under-ice community is an interesting phenomenon known for Arctic Ocean as well as for some rivers and freshwater lakes, including Lake Baikal. Species composition and productive characteristics of the under-ice phytoplankton in Lake Baikal are well studied. During the under-ice blooming, an endemic dinoflagellate Gymnodinium baicalense var. minor Antipova can create more than half of the annual primary phytoplankton production. However, there are still many questions to be answered regarding the factors limiting abundance and proliferation of the under-ice phytoplankton as well as mechanisms facilitating it to persist in Lake Baikal under conditions of the low salinity and low temperature. In present work, we studied dynamics of the development of dinoflagellates and microalgae under the ice cover in Listvennichny Bay of Lake Baikal during the period of February-April 2018. Simultaneously, dynamics of the chemical composition and concentration of atmospheric precipitation was analysed. We observed the under-ice community with domination of endemic dinoflagellate Gymnodinium baicalense var. minor in April. The biomass of this species considerably varied at different days from 0.04 to 10.0 x 103 mg/m3. The results of this study indicated that nutrient supply from precipitation could be an important source of nutrition for organisms developing under the ice, in particular Gymnodinium baicalense var. minor, and could be one of the factors causing the fluctuations in its biomass. We suggested that abrupt significant increases in abundance of G. baicalense var. minor could be a result of their active migration to the area with elevated concentration of nitrogen received from atmospheric precipitation. Such ability may help this species to prosper under the under-ice condition of Lake Baikal.

International audience; Root-knot nematodes (RKNs; genus Meloidogyne) are a class of plant parasites that infect the roots of many plant species. It is believed that RKNs target certain signaling molecules derived from plants to locate their hosts; however, currently, no plant compound has been unambiguously identified as a universal RKN attractant. To address this question, we screened a chemical library of synthetic compounds for Meloidogyne incognita attractants. The breakdown product of aminopropylamino-anthraquinone, 1,3-diaminopropane, as well as its related compounds, putrescine and cadaverine, were found to attract M. incognita. After examining various polyamines, M. incognita were found to be attracted specifically by natural compounds that possess three to five methylene groups between two terminal amino groups. Using cryo-TOF-SIMS/SEM, cadaverine was indeed detected in soybean root cortex cells and the surrounding rhizosphere, establishing a chemical gradient. In addition to cadaverine, putrescine and 1,3-diaminopropane were also detected in root exudate by HPLC-MS/MS. Furthermore, exogenously applied cadaverine is sufficient to enhance M. incognita infection of Arabidopsis seedlings. These results suggest that M. incognita is likely attracted by polyamines to locate the appropriate host plants, and the naturally occurring polyamines have potential applications in agriculture in developing protection strategies for crops from RKN infection.

Electrodialytic separation of Cr(VI) and Cr(III) followed by graphite furnace atomic absorption spectrometry for monitoring of soil extraction was studied. The sensitivity was improved by in-line purification of the solutions and bi-polar pulse cleaning. The detection limit for both Cr(VI) and Cr(III) was 0.01 μg L-1. The system was successfully used to monitor the concentration change during soil extraction with dual solution line filtration. The results demonstrate the difference in concentration changes with the different sources of Cr(VI).

Atmospheric gaseous and particulate pollutants emitted from local or regional sources cause transboundary air pollution. To better understand this environmental issue, it is useful to monitor the free troposphere, reflecting the global air quality, with high temporal resolution. During the summer of 2016, we operated an original on-line monitor on the summit of Mt. Fuji, Japan (3776 m a.s.l.) to measure water-soluble acidic gases and particulate anions in the free troposphere. Mt. Fuji is a free-standing mountain and, therefore, hardly affected by air pollutants emitted from the local region. The lab-made gas/particle collector coupled ion chromatograph successfully provided meaningful data on an hourly basis. The average concentrations of HNO3, SO2, NO3-, and SO42- (n = 64 each) were, respectively 1.8 ± 0.9, 2.3 ± 2.5, 0.22 ± 0.16, and 3.9 ± 2.6 nmol m-3. The gaseous HNO3 was the predominant form compared to particulate NO3-. For the sulfur component, the percentage of particulate form was higher than that of the gaseous one. The high time-resolution monitoring enabled us to classify the observed data based on the air parcel inflow direction to the sampling point even when it changed dramatically. As a result, the oxidation of SO2 to SO42- in atmospheric transport can be discussed for each air parcel. It was suggested that the SO2 oxidation was enhanced in the air parcels that passed over the Asian Continent.

The abundance of humic-like substances in the atmosphere has received considerable attention since these substances play an important role in various atmospheric processes. The wide variety of quantitative techniques used to study humic-like substances produce dissimilar results, making data comparison difficult. Also, global background concentrations and the transfer of atmospheric humic-like substances are poorly known. Here, we compared resins to extract humic-like substances in aerosols, and we measured contents in aerosols from Mt. Fuji. Results show that diethylaminoethyl cellulose resins extracted more humic-like substances than the diethylaminoethyl resin (hydroxylated methacrylic polymer). The mean humic-like substances concentrations in the free troposphere in East Asia is similar to that in Europe, suggesting that the global background level of humic-like substances is 0.05 μg C m−3, based on the humic-like substances concentrations on Mt. Fuji and Mt. Sonnblick. Humic-like substances concentrations, especially fulvic acids concentration, at the summit of Mt. Fuji increased when air masses came from the continent along with the carbon monoxide and ozone.

This work presents diurnal variations of gas- and particle-phase dicarbonyls (glyoxal (Gly) and methylglyoxal (Mgly)) in the atmosphere, which are important compounds that contribute to the formation and growth of atmospheric particulate matter. To obtain variations in partitioning, continuous collection of gaseous dicarbonyls was performed using a parallel plate wet denuder, and at the same time, the dicarbonyls in particle were collected using a spray-type particle collector downstream. Hourly samples were analyzed by high performance liquid chromatography–electrospray ionization–tandem mass spectrometry. This method is advantageous to monitor the gaseous and particulate carbonyls separately without loss during sampling. Sampling was performed in summer and winter in a midsize city (Kumamoto, Japan). The concentrations of the dicarbonyls increased in the summer daytime, which suggests that they are mostly formed by secondary production in the local atmosphere. The dicarbonyls and formaldehyde (HCHO) wer...

Monitoring of trace water in industrial gases is strongly recommended because contaminants cause serious problems during use, especially in the semiconductor industry. An ultra-sensitive trace-water sensor was developed with an in situ-synthesized metal-organic framework as the sensing material. The sample gas is passed through the sensing membrane and efficiently and rapidly collected by the sensing material in the newly designed gas collection/detection cell. The sensing membrane, glass paper impregnated with copper 1,3,5-benzenetricarboxylate (Cu-BTC), is also newly developed. The amount and density of the sensing material in the sensing membrane must be well balanced to achieve rapid and sensitive responses. In the present study, Cu-BTC was synthesized in situ in glass paper. The developed system gave high sensing performances with a limit of detection (signal/noise ratio = 3) of 9 parts per billion by volume (ppbv) H2O and a 90% response time of 86 s for 200 ppbv H2O. The reproducibility of the responses within and between lots had relative standard deviations for 500 ppbv H2O of 0.8% (n = 10) and 1.5% (n = 3), respectively. The long-term (2 weeks) stability was 7.3% for 400 ppbv H2O and one-year continuous monitoring test showed the sensitivity change of

Within the nanopores, junctions and interlayer void space (IVS) in graphene oxide film (GOf), we report that IVS function as the key semipermeable site during sieving. The GOf could filter only dye molecules having nanometer-ranged dimensions. Tinier hydrated ions with angstrom-ranged dimensions couldn't be sieved by GOf. Nature and extent of this molecular sieving property have been justified by observing sieving efficacy and flow times for aqueous solutions of dyes, inorganic salts and their mixtures. GOf also could separate the dyes from mixtures with salts. The flow time followed the trend as: mixtures > salt solutions > dye solutions. PXRD data reveal entering of dye molecules at IVS during sieving. Obviously, a part of dye molecules leaking through the nanopores and junctions of GOf, finally become trapped at the IVS. IVS, therefore has been recognized as the key semipermeable site for molecular sieving in GO. With exploring the insight features of molecular sieving in GOf, this report clearly indicates that IVS needs to be tuned to adopt GOf for various analytical aspects including water purification, desalination and organic inorganic separation.

A gas sensor was developed for arsine (AsH 3 ) which is the most toxic inorganic gas. The sensor was prepared from reduced graphene oxide (rGO), modified with a thin gold film, on an interdigitated array electrode. The conductance of the Au/rGO sensor was monitored in the presence of flowing AsH 3 that was prepared by reduction of aqueous arsenite with borohydride and vaporization of the hydride. Gas sensors fabricated with only rGO or Au did not exhibit AsH 3 sensitivity. However, rGO sensors combined with Au exhibited reversible conductivity enhancement with AsH 3 . The increase in conductivity probably occurred because the AsH 3 depleted adsorbed oxygen on the Au islands, resulting in the enhancement of hole conduction in the rGO film. Responses were observed for sub-ppmv levels of AsH 3 . The amounts of gold and rGO, the GO reduction, and the operating temperature were optimized to obtain a detection limit of 0.01 ppmv (determined from a signal level three times the baseline noise). Interference from other gases and vapors was examined. The sensor responded to NO 2 , but this is not expected to be present in air-quality-controlled clean rooms. AsH 3 is one of the most toxic chemicals used in the semiconductor industry, and the Au/rGO-based AsH 3 sensor is expected to have widespread applications.

After the Fukushima disaster, power generation from nuclear power plants in Japan was completely stopped and old coal-based power plants were re-commissioned to compensate for the decrease in power generation capacity. Although coal is a relatively inexpensive fuel for power generation, it contains high levels (mgkg(-1)) of selenium, which could contaminate the wastewater from thermal power plants. In this work, an automated selenium monitoring system was developed based on sequential hydride generation and chemiluminescence detection. This method could be applied to control of wastewater contamination. In this method, selenium is vaporized as H2Se, which reacts with ozone to produce chemiluminescence. However, interference from arsenic is of concern because the ozone-induced chemiluminescence intensity of H2Se is much lower than that of AsH3. This problem was successfully addressed by vaporizing arsenic and selenium individually in a sequential procedure using a syringe pump equipped with an eight-port selection valve and hot and cold reactors. Oxidative decomposition of organoselenium compounds and pre-reduction of the selenium were performed in the hot reactor, and vapor generation of arsenic and selenium were performed separately in the cold reactor. Sample transfers between the reactors were carried out by a pneumatic air operation by switching with three-way solenoid valves. The detection limit for selenium was 0.008 mg L(-1) and calibration curve was linear up to 1.0 mg L(-1), which provided suitable performance for controlling selenium in wastewater to around the allowable limit (0.1 mg L(-1)). This system consumes few chemicals and is stable for more than a month without any maintenance. Wastewater samples from thermal power plants were collected, and data obtained by the proposed method were compared with those from batchwise water treatment followed by hydride generation-atomic fluorescence spectrometry.

To monitor the fluctuations of dimethyl sulfur compounds at the seawater/atmosphere interface, an automated system was developed based on sequential injection analysis coupled with vapor generation-ion molecule reaction mass spectrometry (SIA-VG-IMRMS). Using this analytical system, dissolved dimethyl sulfide (DMS(aq)) and dimethylsulfoniopropionate (DMSP), a precursor to DMS in seawater, were monitored together sequentially with atmospheric dimethyl sulfide (DMS(g)). A shift from the equilibrium point between DMS(aq) and DMS(g) results in the emission of DMS to the atmosphere. Atmospheric DMS emitted from seawater plays an important role as a source of cloud condensation nuclei, which influences the oceanic climate. Water samples were taken periodically and dissolved DMS(aq) was vaporized for analysis by IMRMS. After that, DMSP was hydrolyzed to DMS and acrylic acid, and analyzed in the same manner as DMS(aq). The vaporization behavior and hydrolysis of DMSP to DMS were investigated to optimize these conditions. Frequent (every 30 min) determination of the three components, DMS(aq)/DMSP (nanomolar) and DMS(g) (ppbv), was carried out by SIA-VG-IMRMS. Field analysis of the dimethyl sulfur compounds was undertaken at a coastal station, which succeeded in showing detailed variations of the compounds in a natural setting. Observed concentrations of the dimethyl sulfur compounds both in the atmosphere and seawater largely changed with time and similar variations were repeatedly observed over several days, suggesting diurnal variations in the DMS flux at the seawater/atmosphere interface.

Acetaldehyde gas sensing using hybrids of reduced graphene oxide (rGO) and transition metal elements, rGO–M (M = oxide/hydroxide of Mn, Fe, Co and Ni) has been investigated. Thin films of GO, rGO and rGO–M on conductive glass were deposited through simple and affordable techniques and characterized using Raman spectroscopy, powder X-ray diffraction patterns, field emission scanning electron microscopy and electrical conductivity measurements. Concentration dependent resistances during the oxidation of acetaldehyde gas in air (10 to 50%) were investigated by using a sensing probe devised from rGO, GO–M and the rGO–M hybrids, of which rGO–Ni exhibited the maximum sensitivity. In rGO–Ni, in combination with rGO the NiOOH precursor can capture electrons (generated from acetaldehyde oxidation) through the holes, while indicating rGO–Ni to be a p-type semiconductor. This report implies the possibility of developing inexpensive graphene based p-type semiconductors for sensing other gases as well.

The sensitivity of an ion chromatography system was improved using electrodialytic post-column enrichment. Even though post-column reactions, such as suppression, have been used to enhance the sensitivity, there are only a few methods available to increase the concentration and improve the sensitivity. Post-column in-line enrichment was achieved with a miniaturized crossflow ion transfer device (ITD) prepared in our laboratory. In the crossflow ITD, separated ionic solutes in the suppressed eluent were transferred into the acceptor solution (in-line purified ultrapure water), which had a flow rate less than that of the eluent. Because of highly efficient ion transfer, the analytes were enriched in the acceptor solution and the enrichment factor was depending on flow rate ratio of acceptor to eluent. Furthermore, the crossflow ITD minimized peak dispersion in the channel. The limit of detection improved by 5.0 ± 0.3 times when the flow rate ratio was 10.

Most quantifications are achieved by comparison of the signals obtained with the sample to those from a standard. Thus, the purity and stability of the standard are key in chemical analysis. Furthermore, if an analyte standard cannot be obtained, quantification cannot be achieved, even if the chemical structures are identified by a qualification method (e.g., high-resolution mass spectrometry). Herein, we describe a universal and analyte standard-free detector for aqueous-eluent-based high-performance liquid chromatography. This universal carbon detector (UCD) was developed based on total organic carbon detection. Separated analytes were oxidized in-line and converted to carbon dioxide (CO2). Generated CO2 was transferred into the gas phase and collected into ultrapure water, which was followed by conductivity detection. The system can be applied as a HPLC detector that does not use an organic solvent as an eluent. The system can be calibrated with a primary standard of sodium bicarbonate for organic comp...

Large amounts of chromium (Cr) compounds are used for manufacturing of various products and various chemical processes. Some inevitably find their way into the environment. Environmental Cr is dominantly inorganic and is either in the cationic +3 oxidation state or in the anionic oxochromium +6 oxidation state. The two differ dramatically in their implications; Cr(III) is essential to human nutrition and even sold as a supplement, while Cr(VI) is a potent carcinogen. Drinking water standards for chromium may be based on total Cr or Cr(VI) only. Thus, Cr speciation analysis is very important. Despite their high sensitivity, atomic spectrometric techniques or induction coupled plasma-mass spectrometry (ICP-MS) cannot directly differentiate the oxidation states. We present here a new electrodialytic separation concept. Sample analyte ions are quantitatively transferred via appropriately ionically functionalized dialysis membranes into individual receptors that are introduced into the ICP-MS. There was no significant conversion of Cr(VI) to Cr(III) or vice versa during the very short (6 s) separation process. Effects of salinity (up to ∼20 mM NaCl) can be eliminated with proper membrane functionalization and receptor optimization. With the ICP-MS detector we used, the limits of detection for either form of Cr was 0.1 μg/L without preconcentration. Up to 10-fold preconcentration was readily possible by increasing the donor solution flow rate relative to the acceptor solution flow rates. The proposed approach permits simultaneous matrix isolation, preconcentration, and chromium speciation.

Indoor and outdoor concentrations of PM2.5-associated perchlorate (ClO4(-)) and chlorate (ClO3(-)) were investigated in Jinan, China, and size-resolved perchlorate and chlorate were studied in Kumamoto, Japan. The average outdoor PM2.5-associated concentrations of perchlorate and chlorate were 4.18 ng m(-3) and 2.82 ng m(-3), respectively, in Jinan. Perchlorate and chlorate were mainly distributed in fine particles, and their approximate PM2.5-associated concentrations were 0.04 ng m(-3) and 4.14 ng m(-3), respectively, in Kumamoto. The ratios of ClO3(-)/ClO4(-) ranged from 18.72 to 360.22 in Kumamoto and from 0.03 to 7.45 in Jinan. The highest concentration of perchlorate (173.76 ng m(-3)) was observed on Spring Festival Eve. This finding and the significant correlation between perchlorate and fireworks-related components (Cl(-) and K(+)) indicated that the fireworks display was a significant source of perchlorate in Jinan. The indoor concentrations of perchlorate and chlorate in Jinan were 3.54 ng m(-3) (range, 0.14-125.14 ng m(-3)) and 0.94 ng m(-3) (range, 0.10-1.80 ng m(-3)), respectively. In the absence of an indoor source of perchlorate, the occurrence of indoor concentrations higher than those found outdoors was a common effect of individual fireworks displays near the sampling sites, coupled with meteorological influences and poor indoor diffusion conditions. The exposure risks of perchlorate and chlorate indoors indicated that the potential risk of perchlorate exposure to children during fireworks displays is deserving of concern.

Leaching behavior of arsenic has been investigated by step-wise ions addition of river sediment near arsenic mine; arsenic was contained in sediment 450 mg kg-1. Leachates were characterized by discriminating arsenite and arsenate under both aerobic and anaerobic. Results indicate that arsenite As(III) and arsenate As (V) were leached from the sediments by step-wise ions addition especially phosphate ion enhanced more leaching of arsenic from sediment under anaerobic mostly was As (V). DOI: http://dx.doi.org/10.3329/bjsir.v49i3.22135 Bangladesh J. Sci. Ind. Res. 49(3), 195-198, 2014

This article presents the effect of phosphate ion on the potential leaching of arsenic from the contaminated sediment under anaerobic conditions near neutral pH for 120 h. Arsenic content in the selected sediments was 450 mg/kg. In the leaching experiment, 50 g of sediment sample was added into 400 mL of five different concentrated 0 (no phosphate), 3, 10, 15, and 20 mg/L phosphate solutions, and leachates were analyzed by distinguishing As(III) and As(V) with the sequential hydride generation flow injection analyzer (SHGFIA). The results indicate that arsenic concentration in the leachates was increased for As(V) up to 72 h, and subsequently As(V) concentration was decreased in the suspension. The leached amount of As(V) concentration in the aqueous phase was increased with increasing the phosphate concentration in the suspensions, and statistically significant correlation (R 2 = 0.9959) was found. Conversely, As(III) concentration in the leachates was almost constant up to 24 h then As(III) concentration was decreased in the suspension. The phosphate ion was potentially leached arsenic, especially As(V) as phosphate (PO4 3−) ion has more charge density than arsenate (AsO4 3−) resulting more As(V) was leached from the contaminated sediment with increasing the phosphate concentration in the suspensions.

PM_中の多環芳香族炭化水素 (polycyclic aromatic hydrocarbons:PAHs) を簡便かつ高感度に分析を行うため，従来の溶媒抽出 (solvent extraction:SE) に代わり，加熱脱着法によるガスクロマトグラフィー質量分析 (thermal desorption–gas chromatography/mass spectrometry:TD-GC/MS) について検討した．本研究では，フィルター捕集したPM_中のPAHsについてTDの条件検討を行うとともに，TD法とSE法の比較検討を行った．その結果，煩雑で時間のかかるSE法に比べTD法では溶媒を用いる前処理が不要なばかりか，同じフィルターを処理した場合桁違いに高感度なことが示された．簡便かつ高感度なため，比較的短いサンプリング (1～3日) を長期間続けることができ，PM_中PAHsの詳細な季節変動の追跡が達成された．PM_濃度は四季を通じて大きな推移を示さない一方，PM_中のPAHsは冬から春に高く，逆に夏にはほとんど観測されなかった．これは冬場の中国大陸におけるPAHsの放出とその移流が主な原因と考えられる．さらに，本法の高感度な特性を生かし，短時間のサンプリングによるPAHsの変動をみることができた．例えば4時間ごとにサンプリングを行い，日内でPAHs濃度が推移する様子を捉えることができた．また，阿蘇山の草原を20 km程度自家用車で走行し，野焼きで発生したPAHsの組成を調べることができた．野焼きの際に得られたPAHsは，季節変動の調査で得られたPAHsに比べて3～4環の低分子量のPAHsが多く，市内で1～3日採取したPM_中のPAHsと組成が異なった．以上のようにTD-GC/MSによるフィルターに捕集したPM中PAHsの分析条件を確立し，特徴ある分析結果を示して本法の有用性を示した．

Electrodialytic ion transfer was studied as a matrix isolation tool for heavy metal determinations. An ion transfer device (ITD) was used for the transfer of heavy metal cations. Under optimized flow rates applied voltage and receptor composition, heavy metal ions were quantitatively transferred at concentrations spanning µg L−1 to mg L−1. As long as the sample pH was acidic, there was no significant sample pH effect on the transfer efficiencies. Significant salt concentrations (>1 mM NaCl), however, decreased the transfer efficiency. This could be ameliorated (up to 5 mM NaCl) by transient instead of continuous sample introduction. The device was applied to the determination of Fe, Cu and Zn in equine and bovine serum; the reproducibility was better than conventional digestion method.

A method to introduce target analytes to a chromatograph from a single drop of whole blood was investigated for minimally invasive monitoring of anionic pharmaceuticals. In this work, salicylate and loxoprofen were examined as organic anions. A micro ion extractor (MIE) has been developed for extraction of inorganic trace anions from whole blood, but this device is not suitable for extraction of pharmaceuticals. In the present study, we improved and optimized the MIE device for organic anion extraction. Various supported liquid membranes were evaluated for use as the ion transfer membrane, with each membrane placed between a droplet sample (donor) and an acceptor solution. A supported liquid membrane of porous polypropylene impregnated with 1-butanol was selected. In addition, the methods for electric field creation and electrode contact were examined to improve the characteristics of the MIE device. The current and extraction time were also optimized. With the optimized method, salicylate and loxoprofen were successfully extracted from a single drop of whole blood. Changes in the concentrations of these pharmaceuticals in blood over time were monitored after administration. As only 25μL of whole blood was required for analysis, repeat measurements could be conducted to monitor changes in the concentrations. This MIE will be useful for monitoring pharmaceutical concentrations in blood.

Preconcentration is an effective way to improve analytical sensitivity. Many types of methods are used for enrichment of ionic solute analytes. However, current methods are batchwise and include procedures such as trapping and elution. In this manuscript, we propose in-line electrodialytic enrichment of ionic solutes. The method can enrich ionic solutes within seconds by quantitative transfer of analytes from the sample solution to the acceptor solution under an electric field. Because of quantitative ion transfer, the enrichment factor (the ratio of the concentration in the sample and to that in the obtained acceptor solution) only depends on the flow rate ratio of the sample solution to the acceptor solution. The ratios of the concentrations and flow rates are equal for ratios up to 70, 20, and 70 for the tested ionic solutes of inorganic cations, inorganic anions, and heavy metal ions, respectively. The sensitivity of ionic solute determinations is also improved based on the enrichment factor. The method can also simultaneously achieve matrix isolation and enrichment. The method was successively applied to determine the concentrations of trace amounts of chloroacetic acids in tap water. The regulated concentration levels cannot be determined by conventional high-performance liquid chromatography with ultraviolet detection (HPLC-UV) without enrichment. However, enrichment with the present method is effective for determination of tap water quality by improving the limits of detection of HPLC-UV. The standard addition test with real tap water samples shows good recoveries (94.9-109.6%).

Chromatographic determination of organic acids is widely performed, but the matrix often calls for lengthy and elaborate sample preparation prior to actual analysis. Matrix components, e.g., proteins, non-ionics, lipids etc. are typically removed by a combination of centrifugation/filtration and solid phase extraction (SPE) that may include the use of ion-exchange media. Here we report the quantitative electrodialytic transfer of organic acids from complex samples to ultrapure water in seconds using cellulose membranes modified with N,N-dimethylaminoethyl methacrylate, which essentially eliminates the negative ζ-potential of a regenerated cellulose membrane surface. The transfer characteristics of the ion transfer device (ITD) were evaluated with linear carboxylic acids. While the ion transfer efficiencies may be affected by the acid dissociation constants, in most cases it is possible to achieve quantitative transfer under optimized device residence time (solution flow rate) and the applied voltage. In addition, the transfer efficiency was unaffected by the wide natural variation of pH represented in real samples. The approach was applied to organic acids in various samples, including red wine, considered to represent an especially difficult matrix. While quantitative transfer of the organic acids (as judged by agreement with standard pretreatment procedures involving SPE) was achieved, transfer of other matrix components was5%. The processed samples could then be chromatographically analyzed in a straightforward manner. We used ion exclusion chromatography with direct UV detection; in treated samples; there was a dramatic reduction of the large early peaks observed compared to only 0.45μm membrane filtered samples.