Question

Calibration data for an electrochemical determination of glucose are given in the table. Glucose Concentration Current Glucose Concentration (ug/mL) (A) Current (ug/mL.) 0.00813 (nA) 0.416 3.01 107 0.0331 1.55 9.82 324 0.109 4.74 33.9 1020 0.267 11.0 123 3470 0.992 37.2 363 9550 Because these data span six orders of magnitude, most of the points will be near the origin if plotted on a lincar graph. A logarithmic plot overcomes this problem, and leads to a more even distribution of the data. Plot log current (nA) as a function of log glucose concentration (pg/mL.)]. Determine the slope(m) and y-intercept (b) for the equation of the line with the form log/curent (nА)) = mlogl glucose concentration (pg/mL)] + What concentration of glucose corresponds to a signal of 75.9 nA?

Answer 1

m = 0.9378

b = 1.5783

glucose concentration = 2.10 ug/mL

Explanation

When we plot log(current) as a function of log(glucose concentration), we get a straight line with equation : y = 0.9378x + 1.5783

slope = m = 0.9378

intercept = b = 1.5783

Given : current = 75.9 nA

y = log(current)

y = log(75.9 nA)

y = 1.88

From the equation of line, x = (y - 1.5783) / (0.9378)

x = (1.88 - 1.5783) / (0.9378)

x = 0.322

Glucose concentration = 10^0.322

Glucose concentration = 2.10 ug/mL

X - O X Chart Tools Layout File Format E F G H I Formula Bar K L N 1 Calibration Curve 000 von AwN Chegal.xlsx - Microsoft Excel (Product Activation Failed) Home Insert Page Layout Formulas Data Review View Design Chart 1 fx B C D Glucose conc. (ug/mL) Current (na) log(conc.) log(current) 0.00813 0.416 -2.089909 -0.38090667 0.0331 1.55 -1.480172 0.1903317 0.109 4.74 -0.962574 0.67577834 0.267 11 -0.573489 1.04139269 0.992 37.2 -0.003488 1.57054294 3.01 0.4785665 2.02938378 9.82 324 0.9921115 2.51054501 33.9 1020 1.53019973.00860017 3470 2.0899051 3.54032947 363 9550 2.5599066 3.98000337 107 123 11 12 13 log(current) y = 0.9378x + 1.5783 14 15 16 17 18 19 20 21 22 23 24 log(glucose concentration) Sheet6 Sheet Sheet1 Sheet8 Sheet9 Ready 2 130% -