The following laboratory data were collected utilizing a chemical reaction to measure the concentration of estrogen in a patient's urine sample.Given the wavelength of maximum absorbance for the assay is 525 nm, and the background is known to be linear between 490 nm and 560 nm, calculate the concentration of estrogen in the patient sample using the Allen correction.
Patient sample absorbance at 490 nm = 0.298
Patient sample absorbance at 525 nm = 0.405
Patient sample absorbance at 560 nm = 0.140
Standard absorbance at 490 nm = 0.180
Standard absorbance at 525 nm = 0.492
Standard absorbance at 560 nm = 0.036
Standard concentration = 25 mg/L

Question

Quizplus · Accepted Answer

The Allen correction serves to correct the absorbance of the sample and standard by removing background absorbance by the interference.The corrected absorbance is then utilized in the Beer's law equation to calculate the concentration of the unknown.Corrected absorbance for patient at 525 nm = A₅₂₅nm - [(A₄₉₀nm + A₅₆₀nm)/2]
= 0.405 - [(0.298 + 0.140)/2]
= 0.186
Corrected absorbance for standard at 525 nm = A₅₂₅nm - [(A₄₉₀nm + A₅₆₀nm)/2]
= 0.492 - [(0.180 + 0.036)/2]
= 0.384
Cᵤ = Aᵤ/Aₛ × Cₛ = 0.186/0.384 × 25 mg/L = 12.1 mg/L

The Following Laboratory Data Were Collected Utilizing a Chemical Reaction