Simultaneous determination of 2,4-D and MCPA in canine plasma and urine by HPLC with fluorescence detection using 9-anthryldiazomethane (ADAM).

A method for the simultaneous determination of 2,4-dichlorophenoxyacetic acid (2,4-D) and 2-methyl-4-chlorophenoxyacetic acid (MCPA) in canine plasma and urine has been developed. This method used derivatization of extracted samples with 9-anthrylmethane (ADAM) for analysis by reversed-phase high-performance liquid chromatography with fluorescence detection. Precision and accuracy were within the accepted limits of 15% and 85-115%, respectively, for both analytes in plasma and urine. Calibration curves for 2,4-D and MCPA in plasma were linear (r2 > 0.99) between 0.50 and 5.0 mg/L and 5.0 and 100 mg/L. Calibration curves for 2,4-D and MCPA in urine were linear (r2 > 0.99) between 5.0 and 70.0 mg 2,4-D/L and 10.0 and 70.0 mg MCPA/L. The lower limit of detection was 62.5 ng/mL for both 2,4-D and MCPA.