A researcher must formulate a series of standards for a fluorescent dye so that all…
CHEMISTRY · Multi-part · AP · Chemistry · Properties of Substances and Mixtures · Properties of Substances and Mixtures
Problem
A researcher must formulate a series of standards for a fluorescent dye so that all absorbance readings fall between 0.100 and 1.200, the range over which the detector response is fully linear. The dye’s molar absorptivity at the selected wavelength is 9.40 × 10^3 L mol⁻¹ cm⁻¹.
Answer the questions below.
(a) For a standard 1.00 cm cuvette, determine the minimum and maximum dye concentrations (in mol L⁻¹) that satisfy the required absorbance window. Present both values in scientific notation.
(b) Microvolume analyses will instead be performed in a 2.00 mm path-length cuvette. Recalculate the allowable concentration range under this new condition.
(c) Explain qualitatively how changing the path length affects the sensitivity of the measurement and discuss one reason a researcher might nevertheless choose the shorter path-length cuvette.