Students at the Northern Alberta Institute of Technology developed a spectrophotometric method for the simultaneous determination of acetylsalicylic acid (ASA), acetaminophen (ACE), and caffeine (CAF) using absorbance at 228,228, 243,243, and 273 nm 273 nm with a 1.000-cm1.000-cm cuvette.

a. What material should the cuvette be made of?
b. Why did the students pick 228,228. 243,243, and 273nm 273nm for their analysis?
c. In developing the procedure, the students sought concentrations that gave absorbance readings between 0.3 0.3 and 1.2.1.2. Why?
d. Determination of unbuffered mixtures resulted in errors up to 7%.7% Acidification of the standards and mixtures resulted in error less than 2.5%.2.5% What was the cause of the initial inaccuracy?
e. Use the matrix operations in Figure 19-2 to find the concentration of each species in an acidified mixture of the three components.

Figure 19-2

Transcribed Image Text:

OH Acetylsalicylic acid HO H N Acetaminophen N Caffeine