Patent ID: 7235170

Claim:
A method for measuring the concentration of glucose in a sample solution by using a biosensor comprising: an electrically insulating base plate; an electrode system comprising a working electrode and a counter electrode disposed on said base plate; and a reagent system comprising an oxidoreductase which catalyzes a reaction of oxidizing glucose to gluconolactone, gluconolactonase and a buffer, wherein said buffer is selected from the group consisting of phthalic acid and its salts, maleic acid and its salts, succinic acid and its salts, phospholic acid and its salts, acetic acid and its salts, boric acid and its salts, citric acid and its salts, glycine, tris(hydroxymethyl)aminomethane, piperazine-N,N′-bis(2-ethane sulfonic acid), N-(2-acetamide)iminodiacetic acid, N,N-bis(2-hydroxyethyl)-2-aminoethane sulfonic acid, 2-morpholinoethanesulfonic acid, imidazole, dimethyl glutaric acid, triethanolamine hydrochloride, collidine, N-tris(hydroxymethyl)methylglycine, and bis(2-hydroxyethyl)iminotris(hydroxymethyl)methane, wherein said reagent system further comprises an electron mediator, and wherein the method comprises determining the concentration of glucose in a sample solution by measuring an oxidation current produced by the oxidation of an electron mediator that has been reduced as a result of oxidation of glucose.