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Poly(ethyleneimine) (PEI) was immobilized on non-woven polyester cloth and examined for application on a simple, rapid and economical "cloth enzyme immunoassay (CEIA)" which was developed originally as polymyxin-CEIA for the detection of Salmonella lipopolysaccharide (LPS). PEI-cloth regardless of the PEI molecular weight, but with the amine group contents of 0.1 ∼ 0.35 meq/g immobilized either in a physisorption-like or chemisorption-like manner, adsorbed LPS rapidly, preferentially and effectively. The captured LPS was then able to be detected qualitatively and quantitatively as an antigen by enzyme immunoassay. PEI-CEIA had a detection limit for Salmonella LPS of 10 ng/ml, which was equivalent to 1.6 × 10[SUB5] cell/ml and was ten times more sensitive than polymyxin-CEIA. It was possible to detect Salmonella LPS in the presence of a 100-fold excess of E. coli LPS.PEI-CEIA was found to be more sensitive and much easier to carry out than polymyxin-CEIA but had the same advantages as polymyxin-CEIA. [ABSTRACT FROM AUTHOR]