HW #3 for Chem 318 – Analytical Chemistry 2

Solute A has a K = 2.5 for an extraction between water (phase 1) and chloroform (phase 2). If 100 mL of a 0.01M solution containing A in water is extracted one time with 400 mL chloroform, what fraction will be extracted? For the same solute, what fraction will be extracted if 5 extractions with 80 mL chloroform each are used (instead of one 400 mL extraction)?

A solute is separated on a column (length: 25 cm) with a peak at 25.5 minutes (retention time) and the baseline peak width of 0.7 minutes. Calculate the number of theoretical plates and the theoretical plate height of this column.

Two compounds (compound 1 and compound 2) are separated on a column with retention time being 14.6 minutes and 16.8 minutes, respectively. The baseline peak width of the two peaks is 0.8 minutes and 1.0 minutes, respectively. Are these two compounds separated completely? Why or why not?

Describe the factors that contribute to the chromatographic peak broadening (hint: Why bands spread?).

List the types of liquid chromatography (categorized based on separation principles) and briefly describe the principles used for separation for each type.

What are the desirable properties for the immobilized liquid stationary phase in a gas-liquid chromatographic column?

What characteristics does an ideal detector for gas chromatography have?

Briefly describe the principle of operation for the following gas chromatographic detectors: 1).Flame Ionization Detector (FID); 2).Thermal Conductivity Detector (TCD); 3).Electron-Capture Detector (ECD).

What advantages does HPLC possess vs GC?

List the components of an HPLC instrument.

Briefly describe the principle of operation for the following HPLC detectors:

1).UV absorbance detector;

2).Fluorescence detector;

3).Refractive-index detector;

4).Electrochemical detector;

5).Mass spectrometric detector. (In addition to going through the slides, you may need to read the textbook and other reference books to finish this question).