Biosensor Having Improved Hematocrit and Oxygen Biases

A reagent composition, comprising:

• a mediator, wherein the mediator is 1,10-phenanthroline-5,6-dione or a derivative thereof;
• at least one magnesium ion;
• and
• at least one counter anion.

A biosensor comprising:

• an electrode support;
• a working electrode disposed on the electrode support;
• a reference electrode disposed on the electrode support;
• and
• a reagent composition deposited over the working electrode and the reference electrode, wherein the reagent composition comprises an enzyme, a mediator, a magnesium ion, and a counter anion, wherein the mediator is 1,10-phenanthroline-5,6-dione or a derivative thereof.

A method for determining the concentration of an analyte in a sample of biological fluid, the method comprising the steps of:

• inserting a biosensor into an analyte monitor, the biosensor comprising:
• an electrode support having at least one electrode thereon;
• and
• a reagent composition disposed on the at least one electrode, the reagent composition comprising:
• an enzyme;
• a mediator, wherein the mediator is 1,10-phenanthroline-5,6-dione or a derivative thereof;
• a magnesium ion;
• and
• a counter anion;
• applying the biological fluid to the biosensor;
• applying a voltage at the electrode;
• measuring the current at the electrode;
• and
• correlating the current measured to the concentration of the analyte.