Excited states in124Xe

The isomer shift in the optical transition Eu II 4f⁷(⁸S ₇ ^2/o )⁶p_3/2 ^(7/2,3/2)4?4f⁷ (⁸S ₇ ^2/o )5d⁹D ₄ ^o , λ=6O4.95 nm, has been measured between the isotope^152gEu(3^?) and its isomer^152mEu(0^?). From the valuev(^152gEu)–v(^152mEu)=736(10) MHz the deformation parameter of^152mEu has been estimated to be^152mβ?+0.25. This value is smaller than^152gβ as obtained from isotope shift measurements and the spectroscopic quadrupole moment. The influence of the shape difference on the decay of^152mEu is discussed.     

Determination of florfenicol amine in channel catfish muscle by liquid chromatography

A method for quantifying florfenicol amine (FFA) in channel catfish muscle was validated according to U.S. Food and Drug Administration guidelines. FFA is the proposed marker residue for the veterinary antibiotic florfenicol in catfish muscle for regulatory surveillance purposes. The method includes acid hydrolysis followed by sample cleanup with ethyl acetate extraction, basification, solid-phase extraction, and quantitation by liquid chromatography with UV detection. The assay was validated at 5 concentrations in the range of 0.075-35 microg/g muscle. The overall mean recovery of FFA from fish tissues fortified at these concentrations ranged from 85.7 to 92.3%, 4.8-17.2% relative standard deviation (RSD). The assay limit of detection was 0.044 microg/g muscle based on analysis of control muscle. Catfish muscle samples containing incurred florfenicol residues were analyzed in quintuplicate with RSD < 5%. Acid hydrolysis has previously been demonstrated to convert florfenicol and its known metabolites to FFA and to release a significant amount of FFA from nonextractable florfenicol residues in tissues containing incurred residues in other species. By using acid hydrolysis, this method should yield a more accurate estimate of the total florfenicol-related residue level in muscle tissue from florfenicol-treated catfish than could be achieved by solvent extraction alone.     

Binary phase shaping for selective single‐beam CARS spectroscopy and imaging of gas‐phase molecules

We report on mode‐selective single‐beam coherent anti‐Stokes Raman scattering spectroscopy of gas‐phase molecules. Binary phase shaping (BPS) is used to produce single‐mode excitation of O₂, N₂, and CO₂ vibrational modes in ambient air and gas‐phase mixtures, with high‐contrast rejection of off‐resonant Raman modes and efficient nonresonant‐background suppression. In particular, we demonstrate independent excitation of CO₂ Fermi dyads at ∼1280 and ∼1380 cm⁻¹ and apply BPS for high‐contrast imaging of CO₂ jet in ambient air. Copyright © 2010 John Wiley & Sons, Ltd.