the invention including the best mode now known to perform the invention these specific examples are not intended to limit the scope of the invention described in this application the following materials equipment and methods were used in all examples unless otherwise stated materials fused silica microcapillaries polymicro technologies inc 3 mercaptopropyltrimethoxysilane mts n succinimidyl 4 maleimidobutyrate gmbs fluka ethanol 200 proof warner graham toluene mallinkrodt tween sigma sodium monophosphate aldrich 2 4 6 trinitrotoluene tnt and 1 3 5 trinitrobenzene tnb anti tnt antibody 11b3 was generated at nrl and another anti tnt antibody was purchased from strategic diagnostics inc all reagents were used as received without further purification and aqueous solutions were prepared in doubly distilled deionized water unless otherwise noted equipment fig1 a schematically illustrates the microcapillary based continuous flow immunosensor used in these examples a rabbit plus peristaltic pump rainin instruments a low pressure rheodyne five way valve sample injector a model 821 fp spectrofluorometer jasco inc and a hp33936b series ii integrator hewlett packard were used a model hp 9114b disc drive hewlett packard inc was utilized to store analog output data from the fluorometer for subsequent analysis all connecting tubes were 0 3 mm i d teflon cole palmer flow buffer the flow buffer comprised of a mixture of sodium monophosphate 10 mm ethanol 2 5 and tween 20 0 01 aldrich all solutions to be analyzed using the microcapillary immunosensor were prepared in the flow buffer antibody immobilization in a microcapillary antibodies were immobilized on the inner walls of the microcapillaries essentially according to the method of bhatia s k l c shriver lake k j prior et al anal biochem 178 408 413 1989 a desired length of fused silica microcapillary 0 80 or 0 55.