Sittampalam and Wilson described the preparation and use of an amperometric sens
ID: 1083130 • Letter: S
Question
Sittampalam and Wilson described the preparation and use of an amperometric sensor for glucose (J Chem. Educ. 1982, 59, 70-73.] The sensor is calibrated by measuring the steady- state current when it is immersed in standard solutions of glucose. A typical set of calibration data is shown here. 5. 0.20 0.40 0.60 0.80 1.00 current (uA 17.2 32.9 52.1 68.0 85.8 A 2.00-mL beverage sample is diluted to 10 mL in a volumetric flask and a steady-state current of 23.6 uA is measured. What is the concentration of glucose in the beverage sample in ppm?Explanation / Answer
the plot of current (uA) vs glucose concentration (ppm) is drawn and shown below
from the equation of best fit, current (uA)=86.15* concentration of glucose (ppm)- 0.49
let x= concentration of glucose in ppm , 1 ppm= mg/L
1 L contains 1 mg
1L= 1000ml
1000ml contains x mg
2ml contains 2/1000 =2x*10-3 mg
this has been diluted to 10ml= 10*10-3 L, concentration = 2x*10-3 mg/(10*10-3) /ml =0.5x mg/ml
current given = 23.6 uA=86.15* 0.5x-0.49
23.6+0.49= 86.15*0.5x
x= 0.56 mg/L