Chemfet Based Microsensors Covered with Ion-Partitioning Polymeric Membranes

 The development of a new type of microsensors based on chemically sensitive field-effect transistors (CHEMFETs) covered with polymeric bulk ion-partitioning membranes is presented. For the construction of the microsensor, a PVC plasticized membrane containing two ionophores, one selective to protons and the other to the analyte cation of interest, is placed on the gate of a pH sensitive field-effect transistor which acts as the transducer. With the use of thin (5–10 μm) ion-partitioning membranes onto the pH-sensitive ISFET gate, the proton displacement out of the membrane and to the pH sensitive gate is fast and reversible. This displacement generates a signal that is directly related to the analyte concentration found in the test solution. Comparing the performance of CHEMFETs and ISEs selective to the monovalent potassium cation and the divalent calcium ion validates this novel CHEMFET response mechanism.     

Carbon nanotube array-based biosensor

Aligned multi-wall carbon nanotubes (MWNT) grown on platinum substrate are used for the development of an amperometric biosensor. The opening and functionalization by oxidation of the nanotube array allows for the efficient immobilization of the model enzyme, glucose oxidase. The carboxylated open-ends of nanotubes are used for the immobilization of the enzymes, while the platinum substrate provides the direct transduction platform for signal monitoring. It is also shown that carbon nanotubes can play a dual role, both as immobilization matrices and as mediators, allowing for the development of a third generation of biosensor systems, with good overall analytical characteristics.     

Oxodealkenylative Cleavage of Alkene C(sp3)−C(sp2) Bonds: A Practical Method for Introducing Carbonyls into Chiral Pool Materials

Reported herein is a one‐pot protocol for the oxodealkenylative introduction of carbonyl functionalities into terpenes and terpene‐derived compounds. This transformation proceeds by Criegee ozonolysis of an alkene, reductive cleavage of the resulting α‐alkoxy hydroperoxide, trapping of the generated alkyl radical with 2,2,6,6‐tetramethylpiperidin‐1‐yl (TEMPO), and subsequent oxidative fragmentation with MMPP. Using readily available starting materials from chiral pool, a variety of carbonyl‐containing products have been accessed rapidly in good yields.     

Phosphate‐Binding Characteristics and Selectivity Studies of Bifunctional Organotin Carriers

The selective recognition of the orthophosphate anion by a series of bifunctional Lewis acidic organotin compounds is investigated. The binding affinity of these carriers to anions, as measured by NMR titrations in CH₂Cl₂ obeyed the potentiometric selectivity order phosphate > sulfate > perchlorate, and provided the corresponding complex‐formation constants. More accurate calculations of these values were obtained by the segmented‐sandwich‐membrane method performed directly inside the liquid polymeric membrane. These carriers were also studied potentiometrically in polymeric liquid membranes. The results indicate that (PhBr₂Sn)₂CH₂ is 2 to 5 orders of magnitude more selective towards phosphate over other oxoanions. These results set the ground for the development of a new series of highly selective anions carriers with a wide range of possible applications.     

Energy Decomposition Analysis of Metal—Metal Bonding in [M2X8]2‐ (X: Cl,Br) Complexes of 5f (U,Np, Pu), 5d (W,Re, Os), and 4d (Mo,Tc, Ru) Elements.

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