The chemical characteristics of complex organic matter in atmospheric aerosols remain poorly understood. Water-insoluble organic matter (WISOM) and water-soluble organic matter (WSOM) in the total suspended particulates collected in the city of Nagoya in summer/early autumn and winter were extracted using multiple solvents. Two fractions of humic-like substances, showing neutral and acidic behavior (HULIS-n and HULIS-a, respectively), and the remaining highly polar part (HP-WSOM) were fractionated from WSOM using solid phase extraction. The chemical structural characteristics and concentrations of the organic matter were investigated using mass spectrometry and Fourier transform infrared (FT-IR) spectroscopy. WISOM and HULIS-n had low O/C ratios (0.1 and 0.4, respectively) and accounted for a large fraction of the organics in aerosols (70%). HULIS-a and HP-WSOM had higher O/C ratios (0.7 and 1.0, respectively), and their concentrations in summer and early autumn were on average ∼2 times higher than those in winter. The mass spectrum and FT-IR analyses suggest the following: (1) WISOM were high-molecular-weight aliphatics (primarily C27-C32) with small proportions of -CH3, -OH, and C═O groups; (2) HULIS-n was abundant in aliphatic structures and hydroxyl groups (primarily C9-C18) and by branched structures; (3) HULIS-a and HP-WSOM contained relatively large amounts of low-molecular-weight carboxylic acids and alcohols (primarily C4-C10); and (4) WISOM and HULIS-n were relatively abundant in amines and organic nitrates.

Chloroform‐extractable green fraction (CEGF) was detected in the supernatant obtained by alkali precipitation from the HCI‐dimethylsulfoxide (DMSO) extract of Pg‐rich soil. In the alkaline solution, the color of CEGF was green and CEGF showed strong Pg‐like absorption bands. Ultraviolet and visible (UV‐VIS) spectral analysis and gel chromatography on Sephadex G‐50 were performed to compare several properties between CEGF and Pg. CEGF, which was purified by gel chromatography on Bio‐Beads SX‐1, displayed strong absorption bands at 609, 562, 445 and 280 inn in the alkaline solution. These absorption bands were almost similar to those of Pg. Furthermore, the UV‐VIS spectrum of CEGF in the organic solvents showed a similar characteristic pattern of 4,9‐dihydroxyperylene‐3,10‐quinone (DHPQ), which was considered to be a chromophore of Pg. Based on the results of gel chromatography on Sephadex G‐50, CEGF mainly consisted of two fractions, corresponding to the G2 and G3 fractions of Pg. These results indicated that the method for extracting CEGF from Pg‐rich soil in the present study was easy and selective and that CEGF was one of the components of, or a closely related substance to Pg. A colorimetric method for the estimation of the CEGF content in soils was developed. The calibration curve of CEGF was linear over a wide range of contents from 2.75 to 220 mg L−1. The CEGF content in twelve samples of various soils was examined. CEGF was detected in all the soil sampled (5 orders) including three samples (3 orders) where Pg was not detected, and the content ranged from 0.07 to 1.66 g kg−1 (dry soil). Therefore, the method for estimating the CEGF content in soils developed in the present study was found to be suitable for various soil orders and it was assumed that CEGF occurred in various soil orders.

To clarify the seasonal fluctuations in air pollution and the effect of long-range transport, we collected airborne particles (n 118) at Dazaifu in Fukuoka, Japan, from June 2012 to May 2013 and measured Pb and SO 4 2 , which are indicators of the long-range transport of anthropogenic air pollutants, as well as their mutagenicity, and other factors. The levels of airborne particles, Pb, and SO 4 2 were very high on March 4, 8, 9, and 19, and May 13, 21, and 22, 2013. The backward trajectories indicated that air masses had arrived from the Gobi Desert and northern China on those days. The mutagenicity of airborne particles was examined using the Ames test on Salmonella typhimurium YG1024. Highly mutagenic airborne particles were mostly collected in winter, and most of them showed high activity both with and without S9 mix. High levels of polycyclic aromatic hydrocarbons (PAHs) were found in many samples that showed high mutagenicity. For the samples collected on January 30, February 21, and March 4, the levels of Pb, SO 4 2 , PAHs, and mutagenicity were high, and the backward trajectories indicated that air masses present on those days had passed through northern or central China. The Japan Meteorological Agency registered Asian dust events at Fukuoka on March 8, 9, and 19, 2013. The results of the present study suggest that high levels of anthropogenic air pollutants were transported with Asian dust. Similarly, long-range transport of air pollutants including mutagens occurred on days when Asian dust events were not registered.Key words transboundary air pollution; airborne particle; Asian dust; China; Ames test; mutagenicity Many epidemiological studies have indicated that ambient air pollution is associated with mortality from lung cancer and respiratory diseases, and others. [1][2][3][4][5] The International Agency for Research on Cancer (IARC) announced that outdoor air pollution and particulate matter, which is a major component of outdoor air pollutants, are carcinogenic to humans (Group 1).6) In recent decades, emissions of air pollutants from mainland East Asia have unprecedentedly increased with the rapid economic growth 7) and long-range transport of air pollutants in East Asia has been reported in recent years. [8][9][10][11][12][13][14] The occurrence and transport of dust storms and anthropogenic air pollutants in East Asia have been monitored using satellite data and ground-based measurements in central Korea. 9,10) Kim et al. 9) reported episodes of anthropogenic pollutant particles that arrived at the Korean peninsula from eastern China and indicated that the anthropogenic pollutant particles were largely detected in the form of smoke over the Yellow Sea region. Takami et al. 12) assessed anthropogenic aerosols and dust particles (Asian dust or Kosa) at Cape Hedo in Okinawa Prefecture, Japan, using high-time-resolution apparatuses and clarified that the anthropogenic aerosols originated from Taiwan and southern China and had been transported in association with a cold front. Ohara et al. 13) an...

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The development of a sensitive and accurate analytical method for monitoring aminoglycosides in food, environmental, and clinical samples is needed for many purposes. This study found that the responses of sodiated and protonated aminoglycosides in hydrophilic interaction chromatography with tandem mass spectrometry were enhanced upon addition of sodium acetate in methanol (5 mg L at a flow rate of 0.2 mL min) as a post-column reagent. The sensitivities of sodiated spectinomycin, kanamycin, gentamicins, neomycin, and amikacin were significantly higher than those of the protonated molecules. Streptomycin and dihydrostreptomycin only formed protonated molecules, suggesting the preferential ionisation of the guanidine moieties in these aminoglycosides. The limits of quantification of these aminoglycosides were 0.19-2.5 ng mL. Notably, this is the first quantification of aminoglycosides that uses the sodiated molecules. The enhancement technique enables us to eliminate a concentration step from the clean-up process from food samples. We also proposed a rapid analytical method for residual aminoglycosides in milk and meat samples; validation showed good accuracy and precision of this method at the Japanese maximum residual limits of aminoglycosides (40-500 µg kg). The application of this method to contaminated bovine tissues revealed remarkably high residual levels of kanamycin. This technique will be useful for the sensitive detection of aminoglycosides not only in food, but also in environmental samples and human plasma.

Persistent and mobile organic compounds (PMOCs) are highly soluble in water, thereby posing a threat to water resource quality. Currently, there are no methods that can accurately quantify guanidine derivative PMOCs, other than 1,3-diphenylguanidine (DPG) and cyanoguanidine (CG), in aqueous media. In this study, we developed a quantitation method that combines solid-phase extraction and liquid chromatography (LC)-tandem mass spectrometry to detect seven guanidine derivatives in aquatic environments and applied it to environmental water samples. Five LC columns were examined, and among them, a hydrophilic interaction liquid chromatography column was chosen owing to its suitable instrument detection limit and retention factor. Method precision was assessed using seven replicate analyses of river water. The corresponding analyte recoveries ranged from 73 to 137% (coefficient of variation = 2.1–5.8%). DPG and CG were detected in ultrapure water samples at levels up to 0.69 and 150 ng L−1, respectively; DPG and CG levels up to 44 and 2600 ng L−1, respectively, were detected in lake water, river water, sewage effluent, and tap water sampled in Western Japan. This is the first reported detection of DPG in the surface water of Japan, revealing that DPG and CG are ubiquitous compounds in aquatic environments. Moreover, this is the first study to detect 1-(o-tolyl)biguanide and N,N′′′-1,6-hexanediylbis(N′-cyanoguanidine) in water. This study provides a foundation for further research on the distribution, fate, and emission source of these pollutants, which is critical to maintain high water quality and to determine regulatory limits for these pollutants. Graphical Abstract

The chemical composition of the hydrophobic acid fraction, which is adsorbed to XAD‐8 resin at low pH and desorbed with high pH solution, of water‐extractable organic matter in soil probably influences its environmental role and, therefore, it is important to recognize the differences in its chemical composition with season and soil horizon. Hydrophobic acid fractions were collected seasonally in 2004 from Oi, Oe/Oa, A and B horizons of Cambisol and were investigated using elemental analysis, high‐performance size exclusion chromatography and 1H nuclear magnetic resonance (NMR) spectroscopy. Atomic ratios of H/C and O/C decreased with increasing soil depth in winter and summer, suggesting that the hydrophobic acid fraction from lower mineral horizons had lower saturated bond content and carbohydrate content than the fractions from upper organic horizons. Based on high‐performance size exclusion chromatography, the molecular weight at peak maximum of the hydrophobic acid fraction decreased significantly with increasing soil depth. The 1H NMR spectra of the hydrophobic acid fraction showed remarkable changes. The signal intensities of carbohydrate protons (δ 3.0–4.3 p.p.m.) in the hydrophobic acid fraction from organic horizons decreased from winter to summer and increased in autumn, while the signal of aliphatic protons (δ 0–3.0 p.p.m.) increased and decreased. In all seasons of the year, the signal intensities of carbohydrate protons were greater in organic horizons and decreased significantly with depth in mineral soil, but the signal for aliphatic protons increased. Our results demonstrate that season and soil depth influence the chemical composition of the hydrophobic acid fraction of water‐extractable organic matter.

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