1. A standard addition experiment was done to determine the concentration of calcium, Ca in wastewater samples by using flame atomic absorption spectrometer (FAAS). 10 mL of aliquots were each added into 50 mL volumetric flasks. The response of the aliquots were measured and the following data were obtained.

Solution	Concentration of added Ca2+ standard (ppb)	Absorbance
Blank	0.0	0.018
Addition 1	12.5	0.094
Addition 2	25.0	0.139
Addition 3	37.5	0.179

a. Sketch and label the standard addition graph.

b. Determine the concentration of Ca in the wastewater if the value of x-intercept from the graph, (CSA) is -7.0 ppb

c. The analysis of calcium can also be performed with flame atomic emission spectrometer (FAES). Differentiate between any two (2) principles in FAAS and FAES.

2. Given the following data:

Compound	Retention time (min)
Unretained species	0.87
Methyl paraben	3.23
Propyl paraben	5.16

a) Calculate the capacity factor, k' for methyl paraben and propyl paraben.

b) Calculate the selectivity factor, a for the two-component mixture.

3. A sample of mixture consisting of several cooking oils is subjected to gas chromatography analysis.

Type of oils	Smoke point CC)
Flax seed	107
Peanut	160
Almond	216
Avocado	271

a) Construct a temperature programming method of this analysis.

b) Suggest the most suitable detector for this analysis.

c) Briefly justify your answer in (b).

4. a) Briefly explain split and splitless injection.

b) State any two (2) criteria of a carrier gas and give any one (1) example.

5. a. Suggest a stationary phase-mobile phase combination of a normal phase HPLC.

b. Arrange the eluting order of n-hexane, 2-hexanol and pentanoic acid using a nonpolar column (Cl 8).

c. Briefly justify your answer in (b).

6. A student is running an HPLC sugar analysis using a C18 bonded column in a 1:4 water:methanol solvent system. He found two peaks in his chromatogram, D-fructose (labeled as 1) and D-glucose ( labelled as 2).

a) Based on the chromatogram, conclude which sugar is more polar.

b) Suggest a method to decrease the elution time of these sugars.

c) Justify your answer in (b).

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