Homogeneous amperometric immunoassay for theophylline in whole blood.
A homogeneous spectrophotometric EMIT immunoassay kit for the quantitation of theophylline in serum or plasma has been modified to produce a rapid, amperometric immunoassay requiring a 50 microliters whole blood sample. The basis of the detection system for the assay is the electrochemical oxidation of NADH produced by G6PDH-labelled theophylline at a potential of +150 mV vs Ag/AgCl using platinised activated carbon (PACE) electrodes. Comparison of the amperometric whole blood method with the conventional spectrophotometric plasma assay produced a reasonable correlation: y = 0.90x - 1.01, (r = 0.98, n = 12). The advantage of the new method is that simple and robust instrumentation can rapidly determine theophylline in whole blood with no sample pre-treatment or separation steps.
Athey
D
D
Department of Clinical Biochemistry, Medical School, University of Newcastle upon Tyne, UK.
McNeil
C J
CJ
Bailey
W R
WR
Hager
H J
HJ
Mullen
W H
WH
Russell
L J
LJ
D015374:Biosensing Techniques; D001774:Blood Chemical Analysis / Q000295:instrumentation / Q000379:methods; D004582:Electronics, Medical; D017248:Enzyme Multiplied Immunoassay Technique / Q000295:instrumentation; D005069:Evaluation Studies as Topic; D006801:Humans; D009243:NAD; D010084:Oxidation-Reduction; D013053:Spectrophotometry; D013806:Theophylline / Q000097:blood*
D009243:NAD; D013806:Theophylline