The development of a fully automated immunoassay for phenytoin utilising fluorescence detection

For a number of years immunoassays have been a major tool in development and determination of drugs in biological fluids. The immunoassay techniques commonly applied in industry at present are those based on micro titre plates consisting of 96 wells. These assays although more complicated, time consuming and labour intensive have for some time been available in an automated format. Immunoassays utilising flowing streams have proven to be quicker, less labour intensive and simpler to perform but until recently have not been available in automated formats. It has been possible with the development of a novel immunoaffinity matrix, POROS Ha, to improve the speed ofimmunoassays without loss of precision and to operate in an automated format. This format involved a AS3000 Hitachi auto sampler, a KlOOO Hitachi automatic flow analyser operating a 16 way injection valve and a F4500 Hitachi fluorescence detector, all controlled using a 486 microprocessor. It was possible, using the system described above, to develop an automated immunoassay producing a sample through put of 40 samples per hour. This system combines the sensitivity and specificity of fluorescence immunoassay together with the automation of a simple flow injection system.