Question 3 [10] 3.1. (i) Describe the differences between a linear ToF mass spectrometer and an orthogonal ToF instrument. (2) (ii) What are the advantages and limitations of these two geometries? (3) (3) 3.2. Describe three ways of introducing a sample into an ICP torch. 3.3. A chromatogram of a mixture of compound X and Y provided the following data (see Table 3.1): Table 3.1: Chromatographic data for U and V 3 Retention time (min) Mobile phase peak 0.81 Compound X 9.35 Compound Y 10.76 Peak width (at base) 0.01 1.13 1.19 (i) For compound X, calculate (correct to 3 sig figs) its retention factor. (1) (ii) Calculate (correct to 3 sig figs) the selectivity factor for compound X and Y. (1)

A gas chromatogram of a mixture of toluene and ethyl (a) Measure w1/2 for each peak to the nearest 0.1 mm. When the thickness of the pen trace is significant relative to the length being measured, it is important to take the pen width into account. It is best to measure from the edge of one trace to the corresponding edge of the other trace, as shown at the bottom of the left column. (b) Find the number of theoretical plates and the plate height for each peak.

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1) Study the chromatograph (below) of a mixture of Compounds A and B, run on the GCs in the teaching labs at CU Boulder. Compound A has the shorter retention time. STAAT 61 1.11 227 RT TYPE AREA XXXX XXXX XXXX AREAS 0.009 55874 44.117 ARIHT 0.61 XX XX XX 1.11 2.27 XX XX XX TOTAL AREA=XX MUL FACTOR=XX 1. What is the retention time of compound A? Compound B? 2. Which compound is present in a larger amount? 3. Which compound has the lower boiling point? 4. What would happen to the retention times of compounds A and B if the column temperature were raised? 5. You suspect that compound B is octane. What can you do to provide supporting evidence for this hypothesis?

Analysis of an unknown plant extract yield two peaks X and Y in a chromatogram, 15.65 and 17.03 min respectively in a 30.0 cm column. The peak base width for X is 1.06 and 1.15 for Y. The average number of plates in the column is

In a chromatographic separation of two components A and B. Component A has a higher Rf value than component B. This implies that: A. Component B has a higher affinity than A for the mobile phaseB. component B elutes first in the columnC. A has a higher affinity than B for the mobile phaseD. Component A has a higher affinity than B for the stationary phase.

5. Here, you can find an example of a paper chromatography experiment. Use the two Chromatograms below the answer the questions that follow: a) (3p) What are the components of unknown sample (X)? b) (12p) Calculate the Rf values for A, B, C in the first chromatogram. d) (10p) When using the 20% Acetone in Water, are the substances strongly attracted to the stationary phase or the mobile Phase? Briefly explain your reasoning. e) (10p) Which substance does show strongest affinity to the stationary phase in the first chromatogram. Briefly explain your reasoning. wwan www 50 80% Acetone in water 20% Acetone in water Finish line 50 45 45 40 40 35 35 30 30 25 20 15 10 10 Starting line A B C D X A B C D X

1,3,5 what the correct answer?

Analysis of an unknown plant extract yield two peaks X and Y in a chromatogram, 15.65 and 17.03 min respectively in a 30.0 cm column. The peak base width for X is 1.06 and 1.15 for Y. The analysis gave a column resolution equal to?