LIQUID-CHROMATOGRAPHIC DETERMINATION USING LANTHANIDES AS TIME-RESOLVED LUMINESCENCE PROBES FOR DRUGS AND XENOBIOTICS - ADVANTAGES AND LIMITATIONS

Lanthanide sensitized luminescence is a very attractive alternative to UV detection and other luminescence techniques, i.e., fluorescence an d phosphorescence, in separation science for the detection of drugs an d xenobiotics because of the large Stokes shift, narrow emission bands and long lifetime, Some published applications of HPLC determination with lanthanide (Ln(3+)) sensitized luminescence detection are reviewe d, Advantages and limitations of this technique are discussed, Normal- phase (NP) HPLC is not influenced by the quenching effect of water whe reas reversed-phase (RP) HPLC is applicable to more compounds than NP- HPLC, However, pH adjustment and the quenching effect of water on Ln(3 +) luminescence are the main drawbacks of RP-HPLC, Elution properties and the need for pH adjustment are two arguments for selecting the mod e of addition of Ln(3+), i.e., pre- or post-column in the HPLC system, Sensitized Ln(3+) luminescence detection is a much more specific meth od of detection than UV or fluorescence detection after HPLC separatio n but nevertheless, in some cases, does not always exhibit a significa nt increase in analytical performance when the donor itself is a stron g fluorophore. The development of more powerful excitation sources cou ld improve the limit of detection of the Ln(3+) sensitized detection t echnique, This review suggests that it would be useful to obtain predi cting factors about the drug to establish whether the latter is suitab le to be measured using an HPLC-Ln(3+) approach.