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Rapid and fingerprinted monitoring of pesticide methyl parathion on the surface of fruits/leaves as well as in surface water enabled by gold nanorods based casting-and-sensing SERS platform
摘要： An effective, simple and portable gold nanorod (Au NR) based casting-and-sensing surface enhanced Raman scattering (SERS) platform was developed for rapid and fingerprinted detection of pesticide methyl parathion. Monodispersed Au NRs with an average length of 60 nm and an aspect ratio of ca. 3 were synthesized through a seed mediated method and then systematically characterized. After a proof-of-concept detection for methyl parathion in DI water and on solid surface, the sensing platform was further applied to real samples (lake water, orange, apple and plant leave) contaminated with methyl parathion. The results show that the sensitivity of the SERS sensor for methyl parathion was satisfactory for real application, with detection limits of 1 μM in spiked lake water and 110-440 ng/cm2 on the surface of various fruits and plant leaves. This study indicates that the developed casting-and-sensing SERS sensor shows great promise to secure agricultural, food and environmental safety.
关键词： lake water,fruits and leaves,Au NRs,methyl parathion,SERS
更新于2025-11-19 16:56:42
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Colorimetric and dark-field microscopic determination of cadmium(II) using unmodified gold nanoparticles and?based on the formation of glutathione-cadmium(II) complexes
摘要： A colorimetric approach is presented for the determinaton of cadmium(II) using unmodified gold nanoparticles (AuNPs) as a colorimetric probe. The assay is based on AuNP aggregation that is induced by the complexes formed between Cd(II) and glutathione (GSH) in a concentrated solution of NaCl. Unmodified AuNPs are known to aggregate in high-salt medium, but GSH can prevent aggregation. In the presence of Cd(II), it will bind GSH, and this will cause the AuNPs to aggregate as indicated by yellow and red dots under dark-field microscopy observation and the formation of a blue coloration. By monitoring the intensity change of AuNPs (as a ratio of absorbances at 600 and 520 nm), Cd(II) can be quantified with a linear response in the 17 pM to 16.7 nM concentration range and a detection limit of 4.3 pM. The method was successfully applied to the determination of Cd(II) in spiked lake water by the standard addition mode, and the detection limit is 4.5 pM.
关键词： Microscopy,Yellow and red dots,Lake water,Glutathione,Ratiometric detection,Cadmium ion,Gold nanoparticle aggregation
更新于2025-09-23 15:19:57
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Remote Estimation of Water Storage Variation of Lakes in Tibetan Plateau Over the Past 20 Years
摘要： Changes in water storage of the lakes at the Tibetan Plateau are regarded as one of the most critical indicators of regional hydrological response to climate change. Different to the conventional hydrological approaches, in this study, we investigate the storage change of four lakes basing on a conceptual lake storage model and the most recent (2001-2016) available satellite observation that cover the lakes. The water surface areas and water levels are derived from MODIS and LEGOS altimetry data, respectively. Based on the regression function between water level and lake area, the net water budgets of the four lakes are estimated for the period. The results show that the storage of Ziling Co rose the fastest at the rate of 8.24 billion m3/a in the past decades, and the rising rate of Qinghai lake has also reached 4.5billion m3/a. The Ngoring Lake which located in the same region with Qinghai Lake changed fluctuatingly, but the water storage has risen 4.9 billion m3 from 2001 to 2016. The water storage of Dogaicoring QC increased steadily at the rate of 1.2 billion m3/a.
关键词： Lake water level – area curve,Water storage changes,Remote Sensing
更新于2025-09-04 15:30:14
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Combining Multispectral Imagery with in situ Topographic Data Reveals Complex Water Level Variation in China’s Largest Freshwater Lake
摘要： Lake level variation is an important hydrological indicator of water balance, biodiversity and climate change in drainage basins. This paper illustrates the use of moderate-resolution imaging spectroadiometer (MODIS) data to characterize complex water level variation in Poyang Lake, the largest freshwater lake in China. MODIS data were used in conjunction with in situ topographic data, otherwise known as the land-water contact method, to investigate the potential of this hybrid water level spatiotemporal variability measurement technique. An error analysis was conducted to assess the derived water level relative to gauge data. Validation results demonstrated that the land-water contact method can satisfactorily capture spatial patterns and seasonal variations in water level fluctuations. The correlation coefficient ranged from 0.684 to 0.835, the root-mean-square-error from 0.79 m–1.09 m, and the mean absolute bias error from 0.65 m to 0.86 m for five main gauge stations surrounding the lake. Additionally, seasonal and interannual variations in the lake’s water level were revealed in the MODIS-based results. These results indicate that the land-water contact method has the potential to be applied in mapping water level changes in Poyang Lake. This study not only provides a foundation for basic hydrological and ecological studies, but is also valuable for the conservation and management of water resources over gauge-sparse regions in Poyang Lake.
关键词： Poyang Lake,water level,in situ topographic data,spatiotemporal variation,MODIS
更新于2025-09-04 15:30:14