Journal of Immunological Methods 1992-04-08

Carbonylmetalloimmunoassay (CMIA) a new type of non-radioisotopic immunoassay. Principles and application to phenobarbital assay.

M Salmain, A Vessières, P Brossier, I S Butler, G Jaouen

Index: J. Immunol. Methods 148(1-2) , 65-75, (1992)

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Abstract

A new non-radioisotopic immunoassay procedure, which we have termed carbonylmetalloimmunoassay (CMIA), is described. The tracers used in this approach are organometallic carbonyl complexes that can be detected at femtomole levels (300-700 fmol) by Fourier transform infrared (FT-IR) spectroscopy. The validity of the technique has been tested in a phenobarbital assay using as the marker a cyclopentadienylmanganese (I) tricarbonyl (cymantrene) moiety, ethyl acetate extraction to separate the free and bound organometallic fractions, and FT-IR spectroscopy to detect the CO stretching modes of the organometallic label. Typical dilution and standard curves obtained with this CMIA procedure are presented. The method was of comparable sensitivity to a [14C] radioimmunoassay (RIA) for the detection of phenobarbital. A comparison of the results for phenobarbital assays by both CMIA and RIA showed that higher titres were obtained using the CMIA method. The standard curves suggest that CMIA is a reliable and reproducible immunoassay procedure for phenobarbital.