IMPROVEMENTS IN DETECTION SENSITIVITY FOR THE DETERMINATION OF IVERMECTIN IN PLASMA USING CHROMATOGRAPHIC TECHNIQUES AND LASER-INDUCED FLUORESCENCE DETECTION WITH AUTOMATED DERIVATIZATION

Improvement in detection sensitivity for the analysis of ivermectin wa s observed through utilization of laser-induced fluorescence detection and by manipulation of chromatographic conditions. Gradient elution u sed in combination with narrow-bore chromatography and conventional fl uorescence detection resulted in a limit of quantitation for the major homologue of ivermectin of 0.01 ng/ml in dog plasma. Laser-induced fl uorescence detection with isocratic chromatographic conditions also re sulted in a limit of quantitation of 0.01 ng/ml in dog plasma, which i s a six-fold improvement over previously reported methods. Introductio n of an automated procedure for the derivatization and injection of sa mples reduced the amount of sample handling, eliminated the potential for analyte/internal standard degradation and contributed to the overa ll ease of analysis.