Determination of digoxin and digitoxin in whole blood.
A liquid chromatography-tandem mass spectrometry (LC-MS-MS) method has been developed and validated for the determination of digoxin and digitoxin in whole blood samples in autopsy cases. Samples were prepared by liquid-liquid extraction (LLE) with ethyl acetate/heptane/dichloromethane (3:1:1). LC separation was achieved using an Atlantis dC(18)-column (2.1 x 50 mm, 3 microm). The time between injections was 11 min. Mass detection was performed by positive ion mode electrospray LC-MS-MS on the ammonium adducts with two transitions for each analyte and one for the internal standard (digoxin-d(3)). Within-day precision was between 8.3 and 10.8%, between-day precision was between 8.7 and 14.2% and accuracy (bias) was between -17.3 and 11.5%. LOQ was 0.1 nmol/L (0.08 ng/mL), with an accuracy and precision of 19% and -17% (digoxin) and 18% and 3% (digitoxin). Matrix effects ranged from 104 to 117%. Good qualitative correlation with previous findings was achieved for 38 autopsy cases. The median (range, number of cases) B-digitoxin and B-digoxin found with the LC-MS-MS method in this very limited material were 9.3 (3.4-23.8, n = 24) and 5.6 (3.4-26.5, n = 4) nmol/L, respectively.
Norwegian Institute of Public Health, Division of Forensic Toxicology and Drug Abuse, P.O. Box 4404 Nydalen, NO-0403 Oslo, Norway. elisabeth.oiestad@fhi.no
Elisabeth Leere
EL
Oiestad
Unni
U
Johansen
Mimi
M
Stokke Opdal
Stein
S
Bergan
Asbjørg Solberg
AS
Christophersen
D001344:Autopsy; D002138:Calibration; D002316:Cardiotonic Agents / Q000097:blood*; D002851:Chromatography, High Pressure Liquid; D004074:Digitoxin / Q000097:blood*; D004077:Digoxin / Q000097:blood*; D006801:Humans; D007118:Immunoassay; D007202:Indicators and Reagents; D013058:Mass Spectrometry; D011786:Quality Control; D012015:Reference Standards; D015203:Reproducibility of Results; D012996:Solutions
D002316:Cardiotonic Agents; D007202:Indicators and Reagents; D012996:Solutions; D004077:Digoxin; D004074:Digitoxin