Multi-analyte analysis of biological fluids with a recycling immunoaffinity column array

A system for isolating and measuring up to 30 analytes in a single biologic al sample is described. The system is based on recycling a pre-labeled samp le through an array of capillary immunoaffinity columns, each packed with,l ass beads, coated with a different antibody, thus enabling each column to i solate and extract a single analyte. Detection of the bound analytes is ach ieved by laser-induced fluorescence (LIF), using a laboratory-built scannin g detector coupled to a fiber-optic spectrometer. The array can be regenera ted up to 200 times, provided a suitable temperature is maintained. The ind ividual immunoaffinity columns are able to bind between 2.9 and 3.6 ng of a nalyte, depending upon the individual column, with lower limits of detectio n (LOD) in the order of 1.6-2.8 pg/ml. The inter- and intra-assay coefficie nts of variation (CV) for all 30 columns in the array were less than 6.03 /- 0.33 at analyte concentrations of 100 pg/ml. Comparison to standard enzy me-immunoassays demonstrated r(2) values in the range of 0.9151-0.9855 when analyzed by least-squares linear regression. (C) 2001 Elsevier Science B.V . All rights reserved.