A dual-channel "on-off-on" fluorescent probe for the detection and discrimination of Fe3+ and Hg2+ in piggery feed and swine wastewater.

Blue-fluorescent blood-CDs were synthesized through a one-pot hydrothermal method using a mixture of chicken blood and trisodium citrate and then explored as a fluorescent probe for detecting Fe3+ and Hg2+. The probe showed excellent selectivity and sensitivity towards Fe3+ and Hg2+ with a dramatic "on-off" fluorescence response. F- recovered the fluorescence quenching by Fe3+, and Al3+ recovered the fluorescence quenching by Hg2+, showing an "off-on" fluorescence response. The blood-CDs were used as an "on-off-on" dual-channel fluorescent sensor for the detection and discrimination of Fe3+ and Hg2+ ions. The probe showed wide linear ranges for determination of Fe3+ (0-100 µM) and Hg2+ (0-120 µM) with low detection limits of 0.23 µM for Fe3+ and 0.17 µM for Hg2+. This probe was practically applied for the determination of Fe3+ and Hg2+ in piggery feed and wastewater with good recoveries. This work provides a fluorescent probe for the quantification of Fe3+ and Hg2+ in livestock feed and environmental water samples.

Taxonomy of Landrevus species group of Velarifictorus Randell, 1964 (Orthoptera, Gryllidae, Gryllinae) with one new species and morphological diversity of Velarifictorusflavifrons Chopard, 1966.

The Landrevus species group includes four Velarifictorus species that are related to Landrevinae crickets (Velarifictoruselephas Gorochov, 1992, Velarifictorusbubalus Gorochov, 1992, Velarifictorusgradifrons Ingrisch, 1998, and Velarifictoruslandrevus Ma, Qiao & Zhang, 2019). A new species of the group is discovered in the Yunnan Province of China, and it is described and illustrated here. Velarifictorusyunnanensis Liu & Yin, 1993 is recognized as a junior synonym of Velarifictorusflavifrons Chopard, 1966. The morphological variety of V.flavifrons ectoparamere is documented and studied.