Photoelectrochemical sensor based on Bi2(Te1-xSex)3 for the sensitive detection of the tetracycline hydrochloride

Tetracycline hydrochloride (TC-HCl) as an antibiotic is widely used in our daily life, but it has posed potential threats to the ecological environment for flowing into the natural environment. To address this issue, The photoelectrochemical (PEC) sensor is first developed for the detection of TC-HCl by comparing and analyzing ternary Bi2(Te1-xSex)3 nanomaterials prepared through different ratios of hydrothermal methods. Specifically, the Bi2(Te1-xSex)3/Indium tin oxide (ITO) electrode can interact with TC-HCl rapidly and selectively which results in a significant reduction of the photocurrent signal. By regulating the ratio of x, it is found that Bi2Te2.85Se0.15/ITO have the best stability and the fastest response time in the detection of TC-HCl. The response/recovery speed of the sensor to TC-HCl is fast to 0.23 s, a low detection limit of 0.08 pmol/l (S/N = 3) and a linear detection fit of up to R2 = 0.992. Moreover, the sensor has good stability and specificity for TC-HCL detection, providing a new perspective for the development of PEC sensors

A Mesozoic fossil lagerstätte from 250.8 million years ago shows a modern-type marine ecosystem.

International audienceFinely preserved fossil assemblages (lagerstätten) provide crucial insights into evolutionary innovations in deep time. We report an exceptionally preserved Early Triassic fossil assemblage, the Guiyang Biota, from the Daye Formation near Guiyang, South China. High-precision uranium-lead dating shows that the age of the Guiyang Biota is 250.83 +0.07/-0.06 million years ago. This is only 1.08 ± 0.08 million years after the severe Permian-Triassic mass extinction, and this assemblage therefore represents the oldest known Mesozoic lagerstätte found so far. The Guiyang Biota comprises at least 12 classes and 19 orders, including diverse fish fauna and malacostracans, revealing a trophically complex marine ecosystem. Therefore, this assemblage demonstrates the rapid rise of modern-type marine ecosystems after the Permian-Triassic mass extinction