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A rhodamine spirolactam derivative ( 1 ) is developed as a colormetric and fluorescent probe for trivalent aluminum ions (Al 3+ ). It exhibits a highly sensitive “turn-on” fluorescent response toward Al 3+ with a 70-fold fluorescence intensity enhancement under 2 equiv. of Al 3+ added. The probe can be applied to the quantification of Al 3+ with a linear range covering from 5.0 × 10 −7 to 2.0 × 10 −5 M and a detection limit of 4.0 × 10 −8 M. Most importantly, the fluorescence changes of the probe are remarkably specific for Al 3+ in the presence of other metal ions, which meet the selective requirements for practical application. Moreover, the experiment results show that the response behavior of 1 towards Al 3+ is pH independent in neutral condition (pH 6.0–8.0) and the response of the probe is fast (response time less than 3 min). In addition, the proposed probe has been used to detect Al 3+ in water samples and image Al 3+ in living cells with satisfying results. [ABSTRACT FROM AUTHOR]

Abstract: The objectives of the study were to identify principal hydrological pathways and source areas of N and P losses by multi-scale monitoring and to estimate total nutrient losses from the catchment. An agricultural catchment with rain-fed agriculture and irrigated paddy fields in subtropical China was monitored with regularly sampling, together with intensive sampling during and after rain storms. Regular weekly sampling showed that the N concentrations in the overland flows from the upland and paddy fields were higher than those from the streams, but lower than those in the subsurface waters. The N concentration, on average, was 10.0 mg L−1 in the well and 1.7 mg L−1 in the spring water, the former was 10.2 times as high as that in the stream waters (1.0–1.5 mg L−1). Nitrogen and P in the overland flows originated dominantly in particulate forms from the uplands (over 70%) and in dissolved forms from the paddy fields. Inorganic N and P dominated in the streams and subsurface waters. The intensive sampling allowed us to establish flow-nutrient concentration relationships and to extrapolate nutrient losses during rainstorms without regular sampling. The extrapolation increased the estimated nutrient losses by about 30% to 50%. The average total nutrient losses within three water years were estimated as 21 kg N ha−1 yr−1 and 1 kg P ha−1 yr−1, accounting for 9.5% and 1.4% of chemical N and P fertilizers applied to the catchment after subtracting the nutrient inputs with irrigation and rainfall. The estimation showed that paddy fields were as important as the uplands in terms of nutrient losses. These results suggest that control of soil erosion and excessive irrigation could be effective to reduce nutrient export through overland flow and subsurface flow. [Copyright &y& Elsevier]

Highlights: [•] A tricarboyanine was first designed as a near-infared chemosensor for Cr3+. [•] The chemosensor showed ratiometric response to Cr3+ with well-resolved emissions. [•] The chemosensor exhibited a high selectivity for Cr3+ over other metal ions. [•] The chemosensor has been used in water samples and living cells successfully. [Copyright &y& Elsevier]

Abstract: A new rhodamine-based compound (1) has been synthesized and applied as an “off–on” chemosensor for Fe3+. The comparison of this method with some other fluorescence methods for Fe3+ indicates that the method can detect Fe3+ in living cells by fluorescence enhancement and color changes with high sensitivity and selectivity. The fluorescence intensity of 1 is significantly increased about 60-fold with 20 equiv of Fe3+ added. Most importantly, the fluorescence changes of the chemosensor are remarkably specific for Fe3+ in the presence of other metal ions, which meet the selective requirements for practical application. Moreover, the experiment results show that the response behavior of 1 towards Fe3+ is pH independent in neutral condition (pH 6.0–8.0) and the response of the chemosensor is fast (response time less than 2 min). In addition, the proposed chemosensor has been used for imaging of Fe3+ in living cells with satisfying results. [Copyright &y& Elsevier]