ION TEST MEANS HAVING A POROUS CARRIER MATRIX

摘要

A test means for determining the presence of an ion in an aqueous test sample is disclosed, as well as a test device incorporating the test means, a method for preparing it and a method for using it. The test means comprises a porous carrier matrix incorporated, substantially uniformly, with a homogeneous hydrophobic composition and with a buffering substance capable of providing a pH in the range of from about 5 to 10. The homogeneous hydrophobic composition contains an ionophore capable of forming a complex with the ion, a hydrophobic vehicle and a reporter substance capable of interacting with the complex of ionophore and ion to produce a detectable response. In a preferred embodiment the homogeneous hydrophobic composition also contains a hydrophobic polymer. Other components such as wetting substances and an interferent removal system can be added to the test means. The method for preparing the test means comprises forming a homogeneous first mixture of the hydrophobic composition and an organic solvent; forming a homogeneous second mixture of a buffering substance capable of providing a pH in the range of from about 5 to 10 and water or a water-miscible solvent or mixtures thereof; incorporating one of the first or second mixture with a porous carrier matrix; drying the incorporated matrix; incorporating the other of the first or second mixture with the dried matrix; and drying the doubly incorporated matrix. The test device comprises an elongated support member having an upper substantially flat face, the test means being affixed to the flat face of the support member.