Publications by authors named "Da-Zhong Shen"

Article Synopsis
  • A cloud point extraction method was developed to analyze four estrogens (E3, E2, E1) and progesterone (P) in water using high performance liquid chromatography and ultraviolet detection (HPLC-UV), utilizing Triton X-114 as the extraction solvent.
  • Various parameters affecting extraction efficiency were optimized, leading to preconcentration factors up to 152 for E1 and detection limits ranging from 0.23 to 5.0 ng/mL for the different estrogens.
  • When applied to wastewater treatment plant effluents, the method found no estrogens present, and recovery tests showed high accuracy with recoveries between 81.2% to 99.5%.
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A method based on cloud point extraction was developed to determine phthalate esters including di-ethyl-phthalate (DEP), di-(2-ethylhexyl)-phthalate (DEHP) and di-cyclohexyl-phthalate (DCP) in environmental water samples using high-performance liquid chromatography separation and ultraviolet detection (HPLC-UV). The non-ionic surfactant Triton X-114 was chosen as extraction solvent. The parameters affecting extraction efficiency, such as concentrations of Triton X-114 and Na2SO4, equilibration temperature, equilibration time and centrifugation time were evaluated and optimized.

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Two new bent oxadiazole bridging benzoacetylene ligands 2,5-bis(4-ethynylphenyl)-1,3,4-oxadiazole (L9) and 2,5-bis(3-ethynylphenyl)-1,3,4-oxadiazole (L10) were synthesized. The coordination chemistry of them with various inorganic Ag(I) salts has been investigated. Seven new coordination polymers were prepared by solution reactions and fully characterized by infrared spectroscopy, elemental analysis, and single-crystal X-ray diffraction.

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Two new bent bis(cyanophenyl)oxadiazole ligands, 2,5-bis(4-cyanophenyl)-1,3,4-oxadiazole (L7) and 2,5-bis(3-cyanophenyl)-1,3,4-oxadiazole (L8), were synthesized. The coordination chemistry of these ligands with various Ag(I) salts has been investigated. Seven new coordination polymers, namely, {[Ag(L7)(H2O)]ClO4}n) (1) (triclinic, P1, a = 9.

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