Reference solution for measuring ionic activity

• US 4,865,698 A
• Filed: 03/17/1987
• Issued: 09/12/1989
• Est. Priority Date: 03/17/1986
• Status: Expired due to Term

• Current Assignee: Fuji Photo Film Co Limited (Fujifilm Holdings Corporation)
• Original Assignee: Fuji Photo Film Co Limited (Fujifilm Holdings Corporation)
• Inventors: Terashima, Masaaki
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Hsing, Ben C.
• Application Number:
  US07/026,920
• Time in Patent Office: 910 Days
• Field of Search: 204/416, 204/403, 204/1 T, 568/774, 429/198, 429/199, 252/408.1
• US Class Current: 205/779
• CPC Class Codes: G01N 27/4165 for pH meters
• CPC Class Codes: G01N 33/84 involving inorganic compounds or pH
• CPC Class Codes: G01N 33/96 involving blood or serum control standard

Abstract

A reference solution for measuring an ionic activity which is utilized at the time of measuring the activity of a particular ion in an aqueous solution by the differential method using ion-selective electrodes, which is characterized by containing the compound having the general formula (I), (II) or (III) and an electrolyte. ##STR1## wherein R₁, R₂, R₃ and R₄ represent hydrogen atom or a lower alkyl group, respectively, and at least, one or R₃ and R₄ is a lower alkyl group, and X represents chlorine atom or bromine atom, ##STR2## wherein R₅ represents hydrogen atom or a lower alkyl group and A represents a hydrogen atom or a halogen atom, and ##STR3## wherein R₆ represents a hydrogne atom or a lower alkyl group. The reference solution of the invention may be preserved for a long period at room temperature without putrifaction, and the compound (I), (II) or (III) in the reference solution does not or scarcely influence upon the potential difference generated in the ion-selective electrode.

Claims

1. A reference solution for measuring the activity of sodium ions, potassium ions or chloride ions in an aqueous solution by a differential method using ion-selective electrodes, said reference solution comprising (a) at least one compound having the general formula (I) ##STR7## wherein R₁, R₂, R₃ and R₄ represent a hydrogen atom or a lower alkyl group, respectively, and at least one of R₃ and R₄ is a lower alkyl group, and X represents a chlorine atom or a bromine atom and (b) at least one electrolyte selected from the group consisting of sodium chloride, ammonium chloride, ammonium nitrite, potassium chloride and lithium acetate.

2. The reference solution of claim 1, wherein said lower alkyl group is methyl group or ethyl group and said X represents a chlorine atom.

3. The reference solution of claim 2, wherein said compound is selected from the group consisting of 3,5-dimethyl-4-chlorophenol, 3-methyl-4-chloropheno, 3,5-diethyl-4-chlorophenol and 2,3,5-trimethyl-4-chlorophenol.

4. The reference solution of claim 1, wherein concentration of said compound is in the range of 10 mg/l to 500 mg/l.

5. The reference solution of claim 1, wherein concentration of said electrolyte is 0.05M to 1M.

7. The reference solution of claim 1, wherein said aqueous solution is a sample of a biological body fluid.

6. The reference solution of 1, which further contains a buffering agent and a water-soluble polymer.

8. a method for measuring activity of sodium ions, potassium ions or chloride ions in an aqueous solution by the differential method using ion-selective electrodes and a reference solution comprising adding to said reference solution (a) at least one compound having the general formula (I) ##STR8## wherein R₁, R₂, R₃, and R₄ represent a hydrogen atom or a lower alkyl group, respectively, and at least one of R₃ and R₄ is a lower alkyl group, and X represents a chlorine atom or a bromine atom and (b) at least one electrolyte selected from the group consisting of sodium chloride, ammonium chloride, ammonium nitrite, potassium chloride and lithium acetate.