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This paper employs a specially designed aggregation‐induced emission fluorogen (AIEgen) to in vivo visualize the process of Hg2+ bioaccumulation in a common species of freshwater zooplankton Daphnia carinata (D. carinata) by two methods, direct Hg2+ absorption and ingestion of Hg2+ contaminated food. We analysed the relevance between photoluminescence (PL, I595/I480) ratios and Hg2+ (CHg2+) and developed the master curve for Hg2+ determination based on measuring the PL intensity of the solution. Meanwhile, fluorescent image analysis showed that the major recipient organs of Hg2+ in D. carinata were the compound eyes and carapace, followed by the intestine and shell gland, but not the brain or heart. The response of D. carinata to Hg2+ via uptake from surrounding water differed distinctly from that through food intake of the algae (Euglena gracilis) contaminated by mercury. When Hg2+ was encapsulated by algae membrane, no fluorescence was detected, and the carapace morphology remained intact after ingesting algae for 80 min, in contrast to the rapid carapace deformation by direct Hg2+ absorption. The D. carinata showed higher mortality by direct Hg2+ immersion than via food ingestion. The reason for the high mortality after Hg2+ immersion was possibly due to carapace deformity after chemical reaction between chitin and mercury, but the biochemical pathway leading to morality needs further study. Schematic illustration of two ways of Hg2+ interacting with Daphnia, either by direct contact or by ingesting Hg2+ contaminated algae, and the radiometric Hg2+ sensing mechanism of the specified AIEgen. [ABSTRACT FROM AUTHOR]

• Salmon spoilage was monitored by H + DQ2-loaded filter paper to detect amine vapours. • The relationship between PL intensity of H + DQ2 and salmon spoilage was established. • The detection conditions of H + DQ2-loaded filter papers for spoilage were optimized. • The AIE method for spoilage has the advantage of simplicity, rapidity and low cost. The method for seafood spoilage detection is far from satisfactory for ensuring food safety and security. Here, we develop a simple and cost-effective method using the filter papers loaded with a dihydroquinoxaline derivative (H + DQ2) to monitor salmon spoilage. The correlation between the content of solid biogenic amines and the photoluminescence intensity (PL) of H + DQ2 induced by amine vapours showed that the PL intensities of H + DQ2 increased with the increase of spoilage, which indicates that it is feasible to evaluate the spoilage degree of salmon based on the PL intensity of H + DQ2-loaded filter papers by semi-quantitation. The optimum detection condition is 75, 50 and 50 g of salmon, 75, 25 and 10 µM H + DQ2 at 0, 4 and 25 °C, respectively. This study provides a quick and simple way for testing amine vapour from fish and provides baseline information for developing an easy-to-use on-site method to evaluate seafood quality for customers. [ABSTRACT FROM AUTHOR]

This paper employs a specially designed aggregation-induced emission fluorogen (AIEgen) to in vivo visualize the process of Hg 2+ bioaccumulation in a common species of freshwater zooplankton Daphnia carinata (D. carinata) by two methods, direct Hg 2+ absorption and ingestion of Hg 2+ contaminated food. We analysed the relevance between photoluminescence (PL, I 595 /I 480 ) ratios and Hg 2+ (C Hg2+ ) and developed the master curve for Hg 2+ determination based on measuring the PL intensity of the solution. Meanwhile, fluorescent image analysis showed that the major recipient organs of Hg 2+ in D. carinata were the compound eyes and carapace, followed by the intestine and shell gland, but not the brain or heart. The response of D. carinata to Hg 2+ via uptake from surrounding water differed distinctly from that through food intake of the algae (Euglena gracilis) contaminated by mercury. When Hg 2+ was encapsulated by algae membrane, no fluorescence was detected, and the carapace morphology remained intact after ingesting algae for 80 min, in contrast to the rapid carapace deformation by direct Hg 2+ absorption. The D. carinata showed higher mortality by direct Hg 2+ immersion than via food ingestion. The reason for the high mortality after Hg 2+ immersion was possibly due to carapace deformity after chemical reaction between chitin and mercury, but the biochemical pathway leading to morality needs further study., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)