Mercury(Hg),arsenic(As) and selenium(Se) are ubiquitous in the environment and exist in a variety of species,which have great influence on their transport,bioaccumulation and toxicity.This review presents the recent research progress in speciation analysis of Hg,As,and Se,with emphasis on enhanced cold vapor generation as interface for liquid chromatography and atomic spectrometry,speciation of volatile species in gas phase,and isotope dilution technique to improve the precision and accuracy of speciation.Hyphenated techniques to characterize the complexes of Hg and As with phytochelatins and chromatographic separation coupled with multi-collector-inductively coupled plasma mass spectrometry to measure species-specific isotopic ratios,are also briefly discussed.
A novel dual-label time-resolved fluoroimmunoassay method was developed for the simultaneous determination of chloramphenicol (CAP) and ractopamine (RAC) residues in 18 swine tissue samples,using anti-CAP and anti-RAC monoclonal antibodies labeled with europium (Eu 3+) and samarium (Sm 3+),respectively.The detection limits for CAP and RAC were 0.06 and 0.25ng/g.The recovery from swine muscle samples was 102%-121% for CAP at spiking levels of 0.1-5ng/g,and 69.8%-85.8% for RAC at spiking levels of 1-10ng/g.The results obtained from the swine tissue samples using this method showed good agreement with those obtained using ELISA and GC-MS,with correlation coefficients (R) between 0.92-0.98.
