Question

The drug Dobutamine (FW=301.38g/mol, C18H23NO3C18H23N03) has a molar absorptivity of 703 at 262nm. One tablet is dissolved in water and diluted to a volume of 2L. If the solution exhibits an absorbance of 0.687 in the UV region at 262nm in a 1- cm cell, how many grams to Dobutamine are contained in the tablet? A. 0.5277g B. 0.58889 C. 9.77x 10g D. 97.778gE. 9.7778g

Answer 1

0.589 g

Step-by-step explanation:

The absorbance (A) of an analyte is related to its concentration (c) through the Beer-Lambert's law.

A = ε . l . c

where,

ε: molar absorptivity

l: optical path length

A = ε . l . c

0.687 = 703 M⁻¹.cm⁻¹ . 1 cm . c

c = 9.77 × 10⁻⁴ M

The molar mass is 301.38 g/mol and the volume of solution is 2 L. The mass of Dobutamine is:

`2L * (9.77 * 10^(-4) mol)/(L)  * (301.38g)/(mol) =0.589 g`