In the analysis of odorants in tequila in Figure 24-21, tequila was diluted with water and extracted four times with dichloromethane (CH2Cl2, (CH2Cl2, b.p. 40°C)40°C). The 400 mL  400 mL of CH₂Cl₂CH₂Cl₂ was evaporated down to 1 mL, 1 mL, and 1 μL μL of the extract was injected on-column onto a poly(ethylene glycol) open tubular column (30 m longx0.53 mm(30 m long x 0.53 mm diameter, film thickness=1 μm thickness=1 μm) initially at 50°C 50°C and then ramped to 230°C. 230°C.
a. Why was the diluted tequila extracted four times with dichloromethane instead of once with a larger volume?
b. Why was on-column injection used?
c. Why was a poly(ethylene glycol) column chosen for this application?
d. What was the phase ratio of the column?
e. Why was a wide-bore 0.53-mm-diameter 0.53-mm-diameter column chosen for this application?

Figure 24-21

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Flame ionization detector response (a) Odor intensity (b) 280 260 240 220 200 180 160 140 120 100 80 60 40 20 0 12 800 6 400 3 200 1 600 800 400 200 100 50 25 Isoamyl alcohol Propanol Isobutanol ▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬ 0 1 Solvent <100 E 5 2 4 Isovaleral- dehyde (chocolate) 164 Butanol 92 6 Isobutanol (sweet) 400 416 430 6 76 519 10 1 8 10 12 561 600 13b 13a Acetaldehyde disoamy acetal I and II Isoamyl alcohol (sweet, fruity) Ethyl facate Acetoin (butter) 0 2 4 6 8 10 12 Ethyl octanoate Furfural Dimethyl trisulfice (sulfury) 5 ? (earthy) 14 16 1 1 1 1 12 14 16 18 20 22 24 26 28 30 801 Linalool 2-Acetyl 5-Methy! furan furfural 824 836 Ethyl decanoate 20 Linalool (floral) 859 865 901 920 943 a-Terpineol 876. 21 22 041 1 026 000 1013 Phenylethyl acetate 50 PC- p-Damascenone (fruity, woody) 1 1 32 34 36 38 40 1 179 2-Phenylethyl alcohol 2-Methyl butyric acid. (fruity, sweaty) 11361 133 Gualacol (smoky) 225 2-Phenyl- ethyl alcohol (floral) 1215 1252 1241 1 304 60% 322 18 20 22 24 26 28 30 32 34 36 38 40 Time (min)