The Adaptation of an Atomic Absorption Spectrophotometer for ELISA Plate Reading

ion Spectrophotometer for ELISA Plate Reading R. A. Srevrus Public Analyst’s Department, London Borough of Southwark A description is given ol the design, construction and application of a module for reading ELISA plates on an Atomic Absorption Spectrophotometer. In common with many other laboratories, this department has been involved recently in the appraisal of the ELISA(enzyme linked immuno-specific assay) technique for the determination of soya in meat productsl,’,3. Setting up for the technique involved a not inconsiderable linancial outlay for items such as repeating pipettes, plate washers, homogenisers, etc. and the further outlay of f1750 for a plate reader was not considered to be a good investment at that early stage. Consideration of the commercially produced plate readers showed them to be quite simple spectrophotometers designed to be insensitive to stray light. This is also a feature of atomic absorption spectrophotometers (AAS) and since this department possessed an early model AA now used only for mercury determina- tions, thought was given to adapting this instrument. The first plan was for a pair of fibre optic bundles to lead the optical beam into and out of th