POSTLAB DISCUSSION-THIN-LAYER CHROMATOGRAPHY This form should be filled out usin

Question

POSTLAB DISCUSSION-THIN-LAYER CHROMATOGRAPHY This form should be filled out using PEN only. Mistakes should be crossed through with a single line only. Note: remember no attach your TLC plates to your notebook pages using clear tape (DO NOTuse staples). TABLE 1: RE VALUES OF KNOWN ANAL IN YLACETATEHEXANE SOLVENT Aceto miniphen Aspirin Caffeine Naproxen D. 75. 8 o 125 o $5 TABLE 2: ANALYSIS OF UNKNOWN L QUID IN ETHYL ACETATEMHEXANE SOLVENT Identity of Unknown und Spot 1 Spot 2* o.15 Spot 3 o. nts, Unknown may contain as few as one or as many as three compounds. Based on your understanding of chromatographic theory e. how a TLc plate works). which ofthe four known analgesics in Table 1 is the most polar, and which is the least polar? Explain your reasoning. A diagram of the TLC plate surface has been provided at the right to assist you.

Explanation / Answer

Answer:

1. In above chromatographic separation as per rf values given in the table-I, Caffeine seems to be more polar as it has ,Rf value lower which is the distance travelled by solvent front substance divided by the distance    travelled by the solvent front.This is due to hydrogen bonding with silicate material loaded on the glass plates or aluminium strips then comes acetaminiphen>Aspirin>Naphroxen. Lower the Rf value greater will be the polarity.

2.In table spot (I) is due to Naproxen as the presence of two benzene rings decreases the polarity where as second spot is due to Caffeine which is more polar due to the presence of hetero atoms which form the hydrogen bond with OH groups present in silicate material. Spot-III is due to acetaminiphen due to the presence of hetero atoms which form hydrogen bonds with silica.

3.Among three compounds Lysine is more polar which contains both NH2 & COOH grops due to hydrogen bonding it it is most polar where as Beta-carotene is less polar as it contains C-H C-C ,& C=C covalent bonds only.

Related Questions

Navigate

• Browse (All)
• Browse P
• Subjects

---

---

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