Kenneth T Kotz | PubMed Health

PubMed2005

Optically addressed droplet-based protein assay.

We demonstrate a new method for performing protein assays with very small volumes ( approximately 1.7 muL to 14 pL). Using a laser to modify local surface energy, we manipulate, fuse, and mix droplets containing horseradish peroxidase and its substrates. A detection limit of approximately 30 attomoles of reacting enzyme was measured by optical absorption. We discuss the possibility of extending this lower limit to zeptomoles of enzyme.

Benzothiazoles↗

PubMed2002

Ultrafast UV pump/IR probe studies of C-H activation in linear, cyclic, and aryl hydrocarbons.

The photochemical C-H activation reactions of eta(3)-TpRh(CO)(2) (Tp = HB-Pz(3), Pz = 3,5-dimethylpyrazolyl) and CpRh(CO)(2) (Cp = C(5)H(5)) have been studied in a series of linear, cyclic, and aromatic hydrocarbon solvents on a femtosecond to microsecond time scale. These results have revealed that the structure of the hydrocarbon substrate affects the final C-H bond activation step, which is in accordance with the known preference of bond activation toward primary C-H sites. In the case of aromatic C-H activation, the reaction is divided into parallel channels involving sigma- and pi-solvated intermediates. Results for the analogous CpRh(CO)(2) molecule have shown that the coordination of the cyclopentadienyl ligand does not play a direct role in the dynamics of the reaction, in contrast to the C-H activation mechanism observed in eta(3)-TpRh(CO)(2) studies.

Journal Article↗