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 is composed of 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 substance and a reporter substance capable of interacting with the complex of ionophore and ion to produce a detectable response. In a preferred embodiment, this invention provides a colorimetric test capable of measuring serum potassium.