Beckman Instruments, Inc.

Chen-Yie Chien

Frank R Shu

Julie S Kim

An indirect potentiometric method and diluent for the analysis of lithium are disclosed. The diluent includes effective amounts of a pH buffer and a non-cationic surfactant comprising at least one hydrophobic group, at least one hydrophillic group and being substantially free of polyoxyethylene groups. Most preferably, the pH buffer is tris-(hydroxymethyl) aminomethane-phosphate, and the surfactant is 2, 4, 7, 9-tetramethyl-5-decyn-4,7 diol. An indirect potentiometric determination of lithium in a clinical sample comprises the steps of mixing the sample with a diluent, contacting an aliquot of the diluted sample with a lithium specific ion selective electrode and at least one ion selective elctrode specifically responsive to a monovalent interfering ion, and measuring both the response of the lithium specific ion selective electrode and the monovalent interfering ion specific ion selective electrode, the responses being an indication of the concentration of lithium in the sample.

Indirect potentiometric method and diluent for analysis of lithium

An indirect potentiometric method and diluent for the analysis of lithium are disclosed. The diluent includes effective amounts of a pH buffer, at least one lithium salt, and a non-cationic surfactant containing at least one hydrophobic group, at least one hydrophillic group and being substantially free of polyoxyethylene groups. Most preferably, the pH buffer is tris-(hydroxymethyl)aminomethane-phosphate, the lithium salt is lithium chloride, and the surfactant is 2,4,7,9-tetramethyl-5-decyn-4,7 diol. An indirect potentiometric determination of lithium in a clinical sample comprises the steps of mixing the sample with a diluent, contacting an aliquot of the diluted sample with a lithium specific ion selective electrode and at least one ion selective electrode specifically responsive to a monovalent interfering ion, and measuring both the response of the lithium specific ion selective electrode and the monovalent interfering ion specific ion selective electrode, the responses being an indication of the concentration of lithium in the sample.

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Ashland, MA, United States of America

Chen-Yie Chien