A rapid spectrofluorometric screening method for enrofloxacin in chicken muscle.

A simple spectrofluorometric method was developed for screening enrofloxacin (ENRO) in chicken muscle. A single-step extraction with acidic acetonitrile gave the best results without further cleanup. Following centrifugation the supernatants were excited at 324 nm and the emission was measured at 442 nm.

Measuring Nitrate in Plant Cells by in Vivo NMR Using Gd3+ as a Shift Reagent.

NMR investigations of nitrate in plant cells and tissues have hitherto been limited by the indistinguishability of the signals from intracellular and extracellular nitrate. Gd3+ is shown to be an effective shift reagent for 14N and 15N nitrate NMR signals, resolving the internal and external nitrate signals in plant tissues, including cell suspensions and root material. However, time-course experiments show that, while the use of Gd3+ allows nitrate levels to be monitored over extended periods, it also has adverse effects on growth and nitrate uptake.