Selective Detection of Hydrazine in the Presence of Excess Electrochemically Active Pharmaceutical Ingredients Using Boron Doped Diamond Metal Nanoparticle Functionalised Electrodes

Detection of the genotoxic impurity hydrazine (HZ) in the presence of active pharmaceutical ingredients (APIs) represents a significant challenge to the pharmaceutical industry. Here we show how the use of electrochemical strategies in conjunction with metal nanoparticle (NP) functionalised polycrystalline boron‐doped diamond (BDD) electrodes enables detection of HZ in the presence of two different electrochemically active APIs. By simply changing the chemical identity of the metal NP, which shifts the detection potential for HZ, it is possible to selectively screen out the API signature from the HZ current – voltage response. HZ detection limits of 11.1 µM (Au NP BDD) and 3.3 µM (Pt NP BDD) in the presence of excess acetaminophen and promazine respectively, were determined using differential pulse voltammetry in quiescent solution.     

High-efficiency energy transfer from carotenoids to a phthalocyanine in an artificial photosynthetic antenna

Two carotenoid pigments have been linked as axial ligands to the central silicon atom of a phthalocyanine derivative, forming molecular triad 1. Laser flash studies on the femtosecond and picosecond time scales show that both the carotenoid S1 and S2 excited states act as donor states in 1, resulting in highly efficient singlet energy transfer from the carotenoids to the phthalocyanine. Triplet energy transfer in the opposite direction was also observed. In polar solvents efficient electron transfer from a carotenoid to the phthalocyanine excited singlet state yields a charge-separated state that recombines to the ground state of 1.