A dual sensor of fluorescent and colorimetric for the rapid detection of lead

Mo(vi) complexes of amide-imine conjugates for tuning the selectivity of fluorescence recognition of Y(iii) vs. Pb(ii)

Two amide-imine conjugates, viz. 3-methyl-benzoic acid (4-diethylamino-2-hydroxy-benzylidene)-hydrazide (L1) and 3-methyl-benzoic acid (2-hydroxy-naphthalen-1-ylmethylene)-hydrazide (L2), have been prepared and used for a further synthesis of Mo(vi) complexes (M1 and M2, respectively). Single crystal X-ray diffraction analysis confirmed their structures. Interestingly, M1 selectively recognizes Y3+ and Pb2+ at two different wavelengths, whereas M2 selectively interacts with Y3+ with a significantly high binding constant, 1.3 × 105 M-1. The proposed sensing mechanism involves the displacement of Mo(vi) by Y3+/Pb2+ from respective Mo(vi) complexes. The TCSPC experiment also substantiates the "turn-on" fluorescence process. A logic gate has been constructed utilizing the fluorescence recognition of cations by M1. DFT studies corroborated the cation-probe interactions and allowed exploring the orbital energy parameters.

Silver nanoparticles as highly efficient and selective optical probe for sulphide via dendrimer formation in aqueous medium

1-[(4-Nitrophenyl)azo]-2-naphthol capped AgNPs were evaluated as a colorimetric sensor for S²⁻ in aqueous medium over pH 4 to 10 with a nanomolar detection limit. The TEM, SEM and AFM images revealed the transition of spherical AgNPs into dendrimers.

A “turn-on” lanthanide complex chemosensor for recognition of lead(ii) based on the formation of nanoparticles

A pincer ligand could fix effectively Tb³⁺ to form complex-based chemosensor, which could further capture Pb²⁺ to induce the formation of nanoclusters as a novel recognition mechanism, accompanied with turn-on phosphorescent response of Tb³⁺ complex.

Biphenyl appended BODIPY derivatives showing combined environmental polarity and heavy metal cation sensing functionality

Novel BODIPY derivatives exhibiting environmental polarity and combined environmental polarity/Hg²⁺ and Pb²⁺ fluorescence sensing properties have been prepared. The sensing properties are the result of a switchable photoinduced electron transfer (PeT) quenching mechanism.

Continuing issues with Lead: Recent Advances in Detection

In the past Pb2+ has been used in many industries, including gasoline, piping, toys, paints, and more. The use of lead has led to a natural increase of lead concentration in the environment especially in air and water. According to the U.S. CDC "no level of lead in blood is considered safe." Exposure to very low amounts of lead can cause several health complications including developmental and neurological disorders. Over the past several years an emphasis has been placed in developing systems that can detect lead at a very low concentration. A great deal of work has been accomplished in the development of Pb2+ sensors that can not only detect but also quantify the amount and in some cases in the presence of other metal ions. Herein, we describe current regulations, mode of exposure and recent development of sensing techniques.