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Show COLLEGE OF ENGINEERING UNDERGRADUATE RESEARCH ABSTRACTS Trevor Jones JulesJ.Magda 10 ACCURACY OF COMMERCIAL GLUCOSE SENSORS WITH VARYING PH AND IONIC STRENGTH Trevor Jones (Jules J. Magda) Department of Chemical Engineering University of Utah Diabetes mellitus is a c o m m o n disease throughout the world affecting millions of people. Each diabetic patient uses some sort of glucose sensor to determine the glucose concentration within their blood. The concentration detected highly affects the proceeding decisions of the diabetic. All glucose sensors use a type of chemical reaction to assay the concentration. A commonly used type by manufacturers is with the enzyme glucose oxidase coupled with amperometry. The device used in this study was the OneTouch UltraMini produced by LifeScan, Inc. which used this c o m m o n type of sensing array. S o m e worry that when exercising, eating particular foods, or taking medication, the change in pH or ionic strength will affect the accuracy of glucose sensors. The focus of this study addressed those issues. The study concludes that pH does not affect the accuracy of glucose sensors using amperometric sensors with glucose oxidase. The experiments were run using PBS buffer with glucose concentrations ranging from 50 - 250 mg/dL.The physiological range of pH in blood is 7.34 -7.45. The values of pH tested were ranging from 6.68 -7.71, well outside of the physiological range in either direction. The OneTouch UltraMini detected results all within the error margin prescribed for each concentration and change in pH.The concentrations remained relatively the same even with large changes in pH. Therefore, diabetics can trust their meters even with changes in pH. The study also concludes that ionic strength does not create a large enough effect to cause diabetics problems. The experiments were run by diluting a concentration of glucose with varying levels of PBS buffer and deionized water. The pH was 7.4 for all experiments with the ionic strength varying from 90 - 200 m M . The physiological range is from 100 - 200 m M . There was a slight downward trend with increasing ionic strength but the results were within the acceptable range for commercial sensors. Therefore, varying ionic strength should not cause any significant problems. |