Permanently oriented antibody immobilization for digoxin determination with a flow-through fluoroimmunosensor.
This paper reports a new flow-through fluoroimmunosensor, the function of which is based on antibodies immobilized on an inmunoreactor of controlled-pore glass (CPG), for determination of digoxin, used in the treatment of congestive heart failure and artery disease. The immunosensor has a detection limit of 1.20 microg L(-1) and provides high reproducibility (RSD=4.5% for a concentration of 0.0025 mg L(-1), and RSD=6.7% for 0.01 mg L(-1)). The optimum working concentration range was found to be 1.2 x 10(-3)-4.0 x 10(-2) mg L(-1). The lifetime of the immunosensor was about 50 immunoassays; if stored unused its lifetime can be extended to three months. A sample speed of about 10-12 samples per hour can be attained. Possible interference from substances with structures similar to digoxin (morphine, heroin, tebaine, codeine, pentazocine and narcotine) was investigated. No cross-reactivity was seen at the highest digoxin: interferent ratio studied (1:100). The proposed fluoroimmunosensor was successfully used to determine digoxin concentrations in human serum samples.
Dpto. Ciencias Analíticas, Facultad de Ciencias, Universidad Nacional de Educación a Distancia (UNED), C/ Senda del Rey n masculine 9, 28040, Madrid, Spain. pfhernando@ccia.uned.es
P
P
Fernández
J S
JS
Durand
C
C
Pérez-Conde
G
G
Paniagua
D000906:Antibodies / Q000276:immunology / Q000378:metabolism*; D002138:Calibration; D004077:Digoxin / Q000097:blood* / Q000276:immunology*; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation* / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D000906:Antibodies; D004077:Digoxin