Ion chromatographic and spectrometric determination of water-soluble compounds in airborne particulates, and their correlations in an industrial area in Attica, Greece

In the time period from June 2005 to May 2006 in 42 sampling campaigns 84 filter samples of airborne particulate matter, coarse (PM_10–2.5) and fine (PM_2.5), were collected using a Gent stacked filter unit in the coastal industrial area of Aspropyrgos in Attica, Greece. The average PM₁₀ (PM_10–2.5 + PM_2.5) concentration was found to be 66 μg · m⁻³, exceeding more than 1.6 times the annual limit of 40 μg · m⁻³. The samples were analysed for Cl⁻, NO₃ ⁻, SO₄ ²⁻, Ca²⁺, Mg²⁺, Na⁺, K⁺ and NH₄ ⁺ using ion chromatography. The data were compared with results obtained with other spectrometric methods, such as inductively coupled plasma-atomic emission spectrometry, atomic absorption spectrometry, energy dispersive X-ray fluorescence and reflectometry. The determined average ionic content comprised about 44% of the PM₁₀ mass. The ionic composition, as well as the possible matrix compounds in both fractions were evaluated by dividing the sampling period into summer and winter season. In the PM_10–2.5/PM_2.5 fraction in summer time the concentrations of Ca²⁺, Mg₂₊ and NO₃ ⁻ were enriched in the coarse fraction. In winter time all species were enriched in the coarse fraction, especially Ca²⁺, Cl⁻ and NO₃ ⁻. NH₄ ⁺ was constantly higher in the fine fraction in summer as well as in winter time. Factor analysis was applied to obtain correlations between cations and anions leading to matrix compounds in both fractions. From the evaluation of the results obtained, some of the local air pollution sources could be identified. Correspondence: Klaus-Michael Ochsenkühn, Laboratory for Trace Element Studies, Institute of Physical Chemistry, NCSR “Demokritos”, Aghia Paraskevi 15310, Athens, Greece     

Determination of total and extractable hydrogen peroxide in organic and aqueous solutions of uranyl nitrate

The development of a spectrophotometric method for the determination of hydrogen peroxide in uranyl nitrate solutions is reported. The method involves the measurement of the absorbance at 520 nm of a vanadyl peroxide species. This species was formed by the addition of a reagent consisting of vanadium (V) (50 mmol·dm⁻³) in dilute sulphuric acid (2 mol·dm⁻³ H₂SO₄). This reagent, after dilution, was also used as an extractant for organic phase samples. The method is simple and robust and tolerant of nitric acid and U(VI). Specificity and accuracy were improved by the application of solid phase extraction techniques to remove entrained organic solvents and Pu(IV). Reverse phase solid phase extraction was used to clean-up aqueous samples or extracts which were contaminated with entrained solvent. A solid phase extraction system based upon an extraction chromatography system was used to remove Pu(IV). Detection limits of 26 μmol·dm⁻³ (0.88 μg·cm⁻³) or 7 μmol·dm⁻³ (0.24 μg·cm⁻³) for, respectively, a 1 and 4 cm path length cell were obtained. Precisions of RSD=1.4% and 19.5% were obtained at the extremes of the calibration curve (5 mmol·dm⁻³ and 50 μmol·dm⁻³ H₂O₂, 1 cm cell). The introduction of the extraction and clean-up stages had a negligible effect upon the precision of the determination. The stability of an organic phase sample was tested and no loss of analyte could be discerned over a period of at least 5 days. The presence of trace levels of reductants interfered with the determination, e.g., hydrazine (<2 mmol·dm⁻³), but this effect was ameliorated by increasing the concentration of the colormetric reagent.     

Determination of bisphenol-a and related compounds in human saliva by gas chromatography—mass spectrometry

Summary A simple and sensitive method for the determination of trace amounts of bisphenol-A (BPA), bisphenol-A diglycidyl dimethacrylate (bis-GMA), bisphenol-A dimethacrylate (bis-DMA) and triethyleneglycol dimethacrylate (TEGDMA) in human saliva is proposed. These materials are used in dental restorations, as composites and sealants, and are sometimes detected in human saliva after dental treatment. The proposed method involves protein precipitation using acetonitrile followed by acidification, evaporation of the solvent and dissolution with dichloromethane prior to injection into a GC-MS. Thermal derivatization in the injection system was used for the identification and quantification of bis-GMA. Clean-up is not necessary using SIM mode. Bisphenol-F (BPF) was used as internal standard. The linear range was 15 to 1000 μg·L⁻¹ for BPA, 50 to 10 000 μg·L⁻¹ for bis-GMA, 50 to 1000 μg·L⁻¹ for bis-DMA and 1 to 100 μg·L⁻¹ for TEGDMA. The detection limits were 3,15,10 and 0.3 μg·L⁻¹ for BPA, bis-GMA, bis-DMA and TEGD-MA, respectively. Validation of the proposed method was carried out by using the standard addition methodology. Samples of 10 mL of human saliva collected 1 h after dental treatment were analysed in order to assess the applicability of the method to detect and quantify such compounds originated from methacrylic resins used in odontological treatment.     

Denitrification in tidal flat sediment, Yangtze estuary

Sediment denitrification rates at six Yangtze River estuary tidal flat locations (mudflats and salt marshes) were measured from July 2003 to October 2004. In winter and summer, spatial distribution of denitrification rates was not great in the Yangtze estuary, while in spring and autumn, denitrification rates had a great spatial distribution because of the human activity effect. The temporal change of denitrification rates was greater. They ranged from 0.2 to 36.4 μmolN·m⁻²·h⁻¹, and were higher in the summertime. The annual average of sediment denitrification rate was 18.2±12.3 μmolN·m⁻²·h⁻¹ in the middle tidal flat and 15.1±9.45 μmolN·m⁻²·h⁻¹ in the low tidal flat in the Yangtze estuary. Data analysis indicated that the temperature was the primary factor controlling the process of denitrification (significant positive correlation, P<0.01); at the same time, the content of sediment total nitrogen (TN) and the molar ratio of sediment carbon and nitrogen (C/N) had significant positive correlation (P<0.05) and negative correlation (P<0.05) with denitrification rates, respectively. In the Yangtze estuary, increasing of water salinity had no significant inhibition of denitrification because of the wide change range of water salinity. Supported by the National Natural Science Foundation of China (Grant Nos. 40173030, 40571006 and 40131020), the Science & Technology Department of Shanghai (Grant Nos. 05DZ120007 and 05JC14059) and China Postdoctoral Science Foundation.     

Fast determination of gold in large mass samples of gold ores by photoexcitation reactions using 10 MeV bremsstrahlung

The determination of gold is based on the photoexcitation reaction ¹⁹⁷Au(γ,γ’)^197mAu with the half-life of 7.73 seconds and energy of emitted gamma-rays of 279 keV. Three 100 ml aliquots of coarsely ground Au-ore (grains <2 mm) corresponding to ca. 150–180 g were irradiated for 20 seconds with bremsstrahlung of maximum energy 10 MeV produced by a microtron at the electron beam current of 30–40 μA, 1–10 times reactivation was applied. After 3 seconds of decay, samples were measured for 20 seconds using scintillation or semiconductor gamma-spectrometry with the detection limits for an ideal sample down to 0.5 μg·g⁻¹ and 0.1–0.2 μg·g⁻¹ of Au, respectively. Content of U and Th undergoing photo-fission increases the detection limits several times.     

Recent trends of plutonium fallout observed in Japan: Comparison with natural lithogenic radionuclides, thorium isotopes

PM_2.5 and PM₁₀ samples were simultaneously collected monthly at a downtown site in Beijing from May 2002 to April 2003 and analyzed by instrumental neutron activation analysis (INAA) combined with organic solvent extraction method for the concentrations and distributions of extractable organohalogens (EOX), including extractable organochlorinated (EOCl), organobrominated (EOBr) and organoiodinated compounds (EOI). The concentrations of EOCl, EOBr and EOI were 10.5–79.2 ng/m³, ND-8.2 ng/m³ and 1.6–8.2 ng/m³ in PM_2.5, respectively, and 37.0–73.3 ng/m³, 1.6–12.8 ng/m³ and 1.6–8.5 ng/m³ in PM₁₀, respectively, which were increasing in the order of EOCl≫EOBr∼EOI. EOCl accounted for 73–88% and 69–91% of EOX in PM_2.5 and PM₁₀, respectively, which showed that EOCl was the major component of the organohalogens. There was a significant difference of EOCl concentrations in PM_2.5 and PM₁₀ in different seasons, which suggested that the concentrations of EOCl in the atmosphere were significantly affected by the meteorologic conditions and anthropogenic activities.     

Seasonal variation and activity size distribution of <Superscript>7</Superscript>Be in ambient air

The seasonal variation of the ⁷Be activities in air and the size distribution of the ⁷Be aerosols were studied by using a continuous air sampler and a five stage cascade impactor. The mean monthly activity level of ⁷Be at the Korea Atomic Energy Research Institute (KAERI) site varied from 0.5 to 4.8 Bq·m⁻³ and revealed a seasonal variation, in which the ⁷Be activity levels were high in winter and low in summer. The mass size distribution showed a bi-modal distribution with a higher peak around 0.49 μm and a smaller peak between 3 μm and 7.2 μm. The activity median aerodynamic diameter (AMAD) decreased with increasing ambient ⁷Be concentrations. The mean residence times by using a mean growth rate of 0.004 μm·h⁻¹ were estimated to be 2.5–6.4 days. The AMAD has an increasing tendency with higher relative humidity. It seemed that the high humidity condition facilitated the growth of the aerosol, resulting in increased deposition rates of the aerosols and the low ⁷Be content in the surface air. The AMAD of the ⁷Be aerosols increased with an increasing temperature, but the temperature dependency of AMAD should be explained with geological and meteorological conditions.     

The application of INAA and beta autoradiography in an investigation of the speciation of iridium in silicates in the presence of carbon phases

Beta autoradiography and progressive acid leaching have been used to investigate the distribution of Ir in silicates in the presence of carbon phases as well as without these phases. Determinations of Ir by neutron activation analysis gave results for the Ir content of basaltic glasses after experiments at 1 bar of 82 ng·g⁻¹ (NNO buffer), 30 ng·g⁻¹ (CCO equilibrium) and 37 ng·g⁻¹ (IW buffer). Iridium solubility in basaltic melt in the presence of graphite and (CO, CO₂) fluid increased from 1.6 μg·g⁻¹ at 0.5 kbar to 6.2 μg·g⁻¹ at 2 kbar. These data give Ir partition coefficients between solid metal and liquid silicate in the presence of carbon phases. Discrete (Ir, Fe) rich phases were discovered in the basaltic melt at 3 kbar and 1250°C preventing the determination of solubility data. Our results provide clear evidence that the iridium solubility in a basaltic melt in the presence of carbon is higher than the solubility of iridium in melts without carbon.     

Improvement in the determination of traces of uranium in aqueous medium having high dissolved organic carbon and chloride ion by alpha-spectrometry

During this work the determination of uranium in the range of μg·L⁻¹ to tens of μg·L⁻¹ was done by alpha-spectrometry after electroplating the aliquots of water sample using (NH₄)₂SO₄ as an electrolyte. In general, the determination of uranium by alpha-spectrometry needs its separation from other transuranics specially thorium. The process described here does not involve any sample digestion and radiochemical separation of uranium from other transuranics. In this method an aliquot (1 to 3 mL) of the sample was dried and dissolve in (NH₄)₂SO₄ and thereafter the sample was electroplated on a stainless steel (SS) planchet by using an electrochemical cell of special design. The proposed techniques have a distinct advantage over the determination of uranium by adsorptive stripping voltammetry (AdSV) in which uranium-chloranilic (2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone) acid complex was used for concentrating the uranium from the solution. Since in the case of AdSv, the determination of uranium was not possible for samples having dissolved organic carbon (DOC) more than 15 mg·L⁻¹ and Cl⁻ concentration is in the range of 40,000 μ·g⁻¹. In the case of spike experiments with ²³²U the recovery was observed in the range of 90–95% in aqueous medium having higher concentration of Cl⁻ and DOC as indicated above.     

Photochemical degradation of typical halogenated herbicide 2,4-D in drinking water with UV/H<Subscript>2</Subscript>O<Subscript>2</Subscript>/micro-aeration

UV/H₂O₂/micro-aeration is a newly developed process based on UV/H₂O₂. Halogenated pesticide 2,4-dichlorophenoxyacetic acid (2,4-D) photochemical degradation in aqueous solution was studied under various solution conditions. The UV intensity, initial 2,4-D concentrations and solution temperature varied from 183.6 to 1048.7 μW·cm⁻², from 59.2 to 300.0 μg·L⁻¹ and from 15 to 30°C, respectively. The concentration of hydrogen peroxide (H₂O₂) and pH ranged from 0 to 50 mg·L⁻¹ and 5 to 9, and different water quality solutions (tap water, distilled water and deionized water) were examined in this study. With initial concentration of about 100 μg·L⁻¹, more than 95.6% of 2,4-D can be removed in 90 min at intensity of UV radiation of 843.9 μW·cm⁻², H₂O₂ dosage of 20 mg·L⁻¹, pH 7 and room temperature. The removal efficiency of 2,4-D by UV/H₂O₂/micro-aeration process is better than UV/H₂O₂ process. The photodecomposition of 2,4-D in aqueous solution follows pseudo-first-order kinetics. 2,4-D is greatly affected by UV irradation intensity, H₂O₂ dosage, initial 2,4-D concentration and water quality solutions, but it appears to be slightly influenced by pH and temperature. There is a linear relationship between rate constant k and UV intensity and initial H₂O₂ concentration, which indicates that higher removal capacity can be achieved by the improvement of these factors. Finally, a preliminary cost analysis reveals that UV/H₂O₂/micro-aeration process is more cost-effective than the UV/H₂O₂ process in the removal of 2,4-D from drinking water.     

Voltammetric determination of the trace amounts of bromate in drinking water after pre-concentration on hydrous γ-Al<Subscript>2</Subscript>O<Subscript>3</Subscript>

A differential pulse voltammetric (DPV) method for the determination of bromate in drinking water, after pre-concentration on γ-Al₂O₃, is proposed. The reduction peak of bromate has been observed at the potential E _p -−1.6 V in an ammonia buffer as a supporting electrolyte. The method has been successfully applied to determine a bromate concentration of 2.5 μg·l⁻¹ in drinking water (RSD=6.1%, n=7). A sample pre-treatment with a column filled with mixed cation-exchange resin in Ag, Ba and H forms was needed before pre-concentration of bromate on alumina.     

Study on the interaction of trypsin with some DNAs and their analytical application by resonance Rayleigh scattering spectra

When trypsin reacts with Herring sperm DNA (hsDNA), Salmon sperm DNA (sDNA), and Calf thymus DNA (ctDNA) to form a complex, the resonance Rayleigh scattering (RRS) was remarkably enhanced and new RRS spectra appear. These new spectra have similar characteristics of RRS spectra. The maximum RRS peaks are at 307 nm (hsDNA, sDNA) and 290 nm (ctDNA), and other peaks are at 350 nm. The scattering intensity is proportional to the concentration of DNA or trypsin; so this intereaction can be used to determine trypsin using DNA or DNA using trypsin. In the determination of DNA using trypsin, the linear ranges for hsDNA, sDNA, and ctDNA are 0–2.3, 0–2.5, and 0–1.9 μg·mL⁻¹, and the detection limits are 0.4, 0.7, and 1.1 ng·mL⁻¹, respectively. In the determination of trypsin using hsDNA, the linear range is 0–30.0 μg·mL⁻¹, and the detection limit is 39.0 ng·mL⁻¹. In this paper, the intereaction conditions were optimized. The affecting factors, chemical properties of the complex, and the composition ratio of trypsin with DNA were investigated. Using trypsin as RRS probe, a sensitive method for the determination of trace amounts of DNA was developed. Translated from Chemical Journal of Chinese Universities, 2006, 27(3) (in Chinese)     

Bioaccumulation and biosorption of stable strontium and <Superscript>90</Superscript>Sr by <Emphasis Type="Italic">Oscillatoria homogenea</Emphasis> cyanobacterium

The ability of living filamentous cells of the cyanobacterium Oscillatoria homogenea to separate stable strontium and ⁹⁰Sr from aqueous solution is demonstrated in this study. On a basis of filamentous cell biovolume, the removal were 43.78 nM·ml·(mm³)⁻¹ and 3129.48 mBq·ml·(mm³)⁻¹ after 240 hour incubation. The optimum pH for strontium uptake is 9±0.3. The increasing biovolume of the blue-green alga elevates sorption. In the liquid culture containing 21.2 mm³·ml⁻¹ filamentous cells and 1000 nM·ml⁻¹ initial strontium concentration, the maximum strontium removal was 455.34 nM·ml·(mm³)⁻¹. At 1200 Lux illumination, the maximum removal value was 58.62 nM·ml·(mm³)⁻¹, and at the initial strontium concentration of 6590 nM·ml⁻¹, 235.40 nM·ml·(mm³)⁻¹ removal was observed. The experimental data fitted to Langmuir isotherm and the model parameters and correlation coefficient (R ²) were q _max = 7.143 μg·(mm³)⁻¹, b = 0.003 and 0.99, respectively.     

Radiation-induced conductivity in poly(phenylene vinylene) derivatives

Using the pulse-radiolysis time-resolved microwave conductivity technique the mobility and decay kinetics of radiation-induced charge carriers is studied in a series of poly(2,5-dialkoxy-phenylene vinylene) derivatives. The lower limit to the sum of the mobilities of the positive and negative charge carriers, Σμ_min, depends strongly on the alkoxy functionalization and ranges from 1.2·10⁻⁷ to 1.4·10⁻⁶ m²/V·s at room temperature. Σμ_min increases with the degree of order in the material. The after-pulse conductivity decay kinetics are disperse and are controlled by a combination of charge recombination and trapping.     

Determination of carbon impurities in epitaxial layers from semiconductor silicon by means of charged particles

The energy-dependent range of charged particles in activation analysis according to the reaction¹²C(d,n)¹³N permits the method to be applied to carbon determination in model epitaxial layers of sufficient thickness. We investigated 100 μm epitaxial layers of the n-type and undoped 50 μ layers as to p⁻ Czochralski substrates. Deuterons were slowed down with Cu and Ta foils having a limiting energy of 13.5 MeV, to 4.2 MeV and 2.9 MeV, respectively. In the resulting activation depths of 52 and 102 μm, the sensitivity of the method, which is 3·10¹⁴ at ·cm⁻³C at E_d=10 MeV in silicon, is reduced to 25% and 10%, respectively. An optimal flux of 0.9 μA·cm⁻² was maintained. After irradiation, 20 or 10 μm were etched off. The sample was inductively fused at 1500 K in a Pb₃O₄/B₂O₃ mixture.¹³N was passed with He as carrier gas into an absorption vessel kept at 77 K, and its activity was measured in γ, γ-coincidence.     

Determination of some banned stimulants in sports by micellar liquid chromatography

Summary A procedure has been developed for the determination, in <12 min, of several stimulants (amphetamine, ephedrine, methoxyphenamine, phenylephrine and phenylpropanolamine) in spiked urine samples after direct injection, using a hybrid micellar mobile phase of 0.15 M sodium dodecyl sulfate and 3% pentanol at pH 7, on a C₁₈ column with UV detection. Recoveries were 94–102% and limits of detection 4.5 ng·mL⁻¹ for methoxyphenamine and 0.39 μg·mL⁻¹ for amphetamine, similar to those obtained for aqueous solutions. Linearity reached 0.99 and intermediate precision was <8.4 and 5.3, for the two different concentrations tested.     

Determination of iodate in rain-water

The determination of iodate in rain-water by neutron activation analysis is described. Iodate is separated by anion exchange. The determination limit of I is 0.02 μg·L⁻¹ for a 20 ml sample. The influence of the sea on the composition of rain-water is demonstrated by the analysis of coastal rain-water. The results indicate that inorganic iodine (I₂ and IO ₃ ⁻ ) is enriched in filtered coastal rain-water relative to the composition of sea-water.     

Local and non-local sources of airborne particulate pollution at Beijing

A new element tracer technique has firstly been established to estimate the contributions of mineral aerosols from both inside and outside Beijing. The ratio of Mg/Al in aerosol is a feasible element tracer to distinguish between the sources of inside and outside Beijing. Mineral aerosol, inorganic pollution aerosol mainly as sulfate and nitrate, and organic aerosol are the major components of airborne particulates in Beijing, of which mineral aerosol accounted for 32%–-67% of total suspended particles (TSP), 10% –70% of fine particles (PM2.5), and as high as 74% and 90% of TSP and PM_2.5, respectively, in dust storm. The sources from outside Beijing contributed 62% (38%–-86%) of the total mineral aerosols in TSP, 69% (52%–-90%) in PM₁₀, and 76% (59%–-93%) in PM_2.5 in spring, and 69% (52%–-83%), 79% (52%–-93%), and 45% (7% – 79%) in TSP, PM₁₀, and PM_2.5, respectively, in winter, while only ≈20% in summer and autumn. The sources from outside Beijing contributed as high as 97% during dust storm and were the dominant source of airborne particulates in Beijing. The contributions from outside Beijing in spring and winter are higher than those in summer, indicating clearly that it was related to the various meteorological factors.     

Determination of nitrogen in steels by alpha-induced prompt gamma-ray spectrometry

The prompt gamma-ray of 871 keV emitted during the bombardment of steels by 5 MeV alpha particles were used to determine nitrogen by means of the reaction¹⁴N(α, pγ)¹⁷O. The method is non-destructive, rapid and experimentally simple. It has a sensitivity of about 7 μg·g⁻¹. In the nitrogen concentration range of 10¹–10² μg·g⁻¹ the relative precision of the method is about 3%. The accuracy of the method compares with that of other nuclear methods. Presented at the 5th Symposium on Recent Developments in Activation Analysis, Oxford, 17–21 July, 1978.     

Pharmacokinetics,tissue distribution and excretion of a recombinant fusion protein <Superscript>125</Superscript>I-rhTNT-IL2

This study examined the tissues distribution and pharmacokinetics of rhTNT-IL2, a fusion protein, in rats and macaques after iv. injection. The rhTNT-IL2 was labeled with ¹²⁵I. The ¹²⁵I-rhTNT-IL2 was administered into rats and macaques at a dose of 250 μg·kg⁻¹ and 125 μg·kg⁻¹, respectively. Upon administration, rhTNT-IL2 declined in tri-exponentially with the half-lives of 1.78 h (T _1/2α), 25.06 h (T _1/2β), 114.19 h (T _1/2γ) for rats and 1.87 h (T _1/2α), 9.82 h (T _1/2β), 43.17 h (T _1/2γ) for macaques. The fraction of ¹²⁵I-rhTNT-IL2 excreted in feces was low (about 1%), while the majority of ¹²⁵I-rhTN-IL2 was excreted in urine. The tissue distributions showed that the liver, spleen and heart were major organs for deposition of the fusion protein in rats and macaques in 48-hour post-injection, and the fusion protein could not penetrate through blood brain barrier.