Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

when constructing a calibration plot (curve) for a FD&C food dye you must ( you

ID: 888178 • Letter: W

Question

when constructing a calibration plot (curve) for a FD&C food dye you must ( you can select more than one answers)

a. Only use solutions with absorbance readings above 1.50
b.Take the absorbance readings at any wavelength, so long as the same wavelength is used in all readings.
c.Prepare a dilution series from a stock dye solution whose concentration is known. That is, given a dye solution of defined concentration, you prepare a set of dilutions in such a way that the concentration of each dilution is known.
d.Plot the absorbance (A) vs. concentration (C), which by Beer's Law will give you a line with slope l

Explanation / Answer

Using solutions with absorbance readings above 1.50, the sample tramsmits so little light that is not measurable.

At the peak absorbance, the absobance strength of light will be at the highest and rate of change in absorbance with wavelength will be the smallest.

The first step in performing the experimentis to determine the calibration curve, by preparing samples with known concentration and measuring their

absorbance values.

The plot produces a linear plotof absorbance versus concentration, with a slope and an intercept of zero.

Therefore, the answers are options b, c and d.