Liquid chromatographic determination of ivermectin in animal plasma with trifluoroacetic anhydride and N-methylimidazole as the derivatization reagent.
Ivermectin is a potent anthelmintic agent which was detected at low concentrations in cattle plasma by LC after conversion to a fluorescent derivative. This was accomplished by reaction with acetic anhydride (AA) and pyridine for 24 h at 100 degrees C or with AA and N-methylimidazole (NMIM) for 1 h at 95 degrees C. Substituting trifluoroacetic anhydride (TFAA) for AA reduced the reaction time to less than 30 s at 25 degrees C, yielding an intensely fluorescent derivative with substantially fewer reagent by-products. The need for further sample preparation after derivatization with TFAA-NMIM was thereby eliminated, and detection limits of less than 20 pg ml-1 ivermectin could be achieved with 1 ml of plasma by a considerably simpler analytical procedure.
de Montigny
P
P
Merck Sharp and Dohme Research Laboratories, Rahway, NJ 07065.
Shim
J S
JS
Pivnichny
J V
JV
D000089:Acetic Anhydrides; D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D005463:Fluoroacetates; D007093:Imidazoles; D007202:Indicators and Reagents; D007559:Ivermectin / Q000097:blood*; D012015:Reference Standards; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet
D000089:Acetic Anhydrides; D005463:Fluoroacetates; D007093:Imidazoles; D007202:Indicators and Reagents; C017958:trifluoroacetic anhydride; D007559:Ivermectin; C018100:1-methylimidazole