Question starts from \"the sample injected contained a mixture of C6H14 isomers

Question

Question starts from "the sample injected contained a mixture of C6H14 isomers .." Identify and order in which each isomer present in the sample peak. You do not need to print off a NIST report for each compound... that would generate a lot of unneeded paper. Pre-Lab Questions: Padias p115 #4 and 12 and the following question. Below is a table with the results of the GC trace to the right. The sample injected contained a mixture of C6H14 isomers: n-hexane, 2,3-dimethyl butane, and 3-methylpentane. Identify the order in which the isomers eluted from the column and the relative percentage of each isomer present in the sample. Peak Ret. Time (min) Area (pA) 1.65 5432 2345 1.73 3 4875 2.24 Items to cover in your post-lab report: What substance had the largest peak in the TIC from the GCMS? Which substance came off the column first? Which substance came U off the column last? Why did those two substances elute off the L

Explanation / Answer

Branched alkanes contain weaker van der waals forces because of the smaller area of contact between the molecules. So less energy is needed to overcome the intermolecular force. Lower boiling point compounds eluted first (or more polar compounds elutes first). It depends up on the interaction of the compound with GC stationary phase.

The boiling point order: n-Hexane>3-methyl pentane>2,3-dimethyl butane

Thus, elution order in GCMS: n-Hexane<3-methyl pentane<2,3-dimethyl butane

Related Questions

Navigate

• Browse (All)
• Browse Q
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.