plreasehelp with these labs 11 and 12 yhank you due i 24 hours time olease do it carefully thank youPage |1
CHM 221-02, 03 – Isolation of a Natural Product – Orange Oil
Overview and Instructions for the Lab Report
Posted: Monday, Nov.30 (due Wednesday, Dec. 16)
Overview
Various methods of extraction have been used over the centuries to isolate active ingredients in plant
materials. These natural products have various uses such as for flavorings and medicines. Hot water
often provides a means to remove these products, even though some of them are not actually soluble in
water.
Essential oils are an example of an important group of products obtained by steam distillation. This
process allows hot water to raise the temperature of the plant materials for extraction without the risk
of decomposing the substances at higher temperatures .
Method
A distillation apparatus is used to allow the mixture to heat continually over a period of time. The
product of interest can slowly vaporize. Additional solvent (H2O) can be added as needed keep liquid in
the flask and allow the process of extraction from the plant material.
Instructions – Lab Report
1. Read pp. 1-2 of the “Lab Handout” on Moodle provided for this reaction. Watch the lab video
to see how the glassware is put together. Study the procedure on pp. 3-5 to understand the setup of the distillation.
2. Review the “Background Material” provided for additional information about this process,
including the many different ways in which it can be done!
3. Your report will be to submit the answers to the “Lab Questions” , given below.
Lab Questions
NOTE: Use complete sentences in order to be eligible for full credit. Each question should have at least 3
sentences for a response.
1. Water is used as a solvent, and yet the major products of interest are terpenes, which are not water
soluble. Briefly explain how this process works: Consider the following questions: How does the desired
product material get extracted and where does it go in this method? How is this like brewing tea? How
is it different? (See p. 2 of the lab handout for some information, as well. )
2. A claisen adapter is used as part of the glassware. What is the purpose of this specific design during
the process? (Hint: See Step #13 of the lab procedure, and see the file on Moodle with the description.)
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3. Describe terpenes as a class of compounds, including the general chemical structural features and
their uses.
4. Give three examples of some of the compounds found in essential oils, with chemical structure, and
what they contribute to the resulting oils.
5. Many extraction methods are used today and have been used over the centuries. In particular,
consider two of these methods – the “cold-pressing” method and the “microwave-assisted
hydrodistillation” (as described in the “Methods” background article on Moodle). Write a brief
description of the features and advantages of each of these two methods. NOTE: One of these methods
is considered a traditional and the other an innovative method! The answer to this question must be at
least 6 sentences.
6. There are many commercial kits available today for home use in the process of extraction of essential
oils. Find a reference for such a kit, and describe the equipment that is contained within the kit. Include
an explanation of how the method from the kit follows the same process as described in the scholarly
articles you have read. Hint: Google “distillation of essential oils”. You can even buy them on Amazon,
of course!
7. In the “Methods” article on Moodle, steam distillation (as described in this lab experiment) is actually
called hydrodistillation (HD). Another method in that article is actually called steam distillation. Compare
these two methods, both of which are called steam distillation by some scientists.
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CHM 221-02, 03 – Gas Chromatography
Overview and Instructions for the Lab Report
Posted: Monday, Nov.30 (due Wednesday, Dec. 16)
Overview
Gas chromatography (GC) is an important aspect of chemical analysis of mixtures. The method allows
separation of individual substances which have different degrees of attraction to the substrate of the
packing material in the column, called the stationary phase. Depending on the detector, further analysis
may be done on the identity of the substances. The retention time (time for the substance to completely
pass through or elute from the column) is the variable obtained with any detector, and cal be used to
compare to the retention time for compounds of known structure. A mass spectrometer (MS) is a
common detection system in research labs. A mass spectrometer will provide specific structural
information about the substance for further identification.
Method
The method allows analysis of very small amounts of material, typically a microliter (L), even though
the vial of the mixture contains far more. The sample is injected with a microsyringe, either manually or
by an automated system containing a rack of sample vials.
A column must be chosen which will distinguish among the attractive forces among the possible
substances in the mixture. These columns have a (proprietary) solid packing material, and the sample is
injected, then vaporized into an inert gas stream (the mobile phase), which passes through the column
and then to the detector system. [NOTE: Column packing is chosen based on the recommendations of
the manufacturer of that column packing for the substances of interest supplied by the lab analysts.]
The stronger the interaction of the substance with the solid packing material (stationary phase), the
longer the retention time for that substance.
The amount of a substance can be obtained by determining the area of (integrating ) the peak from the
substance on the chromatogram.
Instructions – Lab Report
1. Read the “Lab Handout” on Moodle provided for this reaction. [Note: There are some typos
with “CG” instead of “GC” in several places!]
2.
Your report will be to submit the answers to the “Lab Questions” , given below.
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Lab Questions
NOTE: Use complete sentences in order to be eligible for full credit, unless the question is presenting a
calculation. Each question should have at least 3 sentences for a response, if an explanation or
description is expected.
1. Complete the calculations for the % of each of components A and C in the chromatogram on p. 5 of
the lab handout. The value for % B is already shown in the example on p. 4.
2. The analysis of the results of the chromatogram in Fig 4 is described on p.5 of the lab handout. Briefly
summarize the assumptions and prior information needed in order to identify the unknown, according
to this description.
3. The following chromatogram shows the effect of changing temperature on the results of a
chromatogram of the sample in each case:
Briefly explain why you think the retention times change as they do with temperature. What does
this show about the experimental conditions needed for a good chromatographic separation and
analysis?
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4. The following chromatogram has included the results from the mass spectroscopy results (the mass
spectrum). Infrared spectroscopy (IR) is another type of detector which is often used and which would
provide additional, structural information about the substance eluting at each time (peak).
.
If you did not have such additional detectors, but only had the retention time, what might you do in the
lab to further characterize the mixture you are interested in? This would include taking advantage of the
information from the retention times of known compounds, such as you see in Figure 4 of the lab
handout. Note: This is a general question about the approach you would use, not specifically to the
compounds in Figure 4.
Think of what we have studied so far this semester, and suggest two or three approaches you would try
in order to confirm the identity of each substance in the mixture. Assume you have enough sample to do
macroscale analyses or procedures.
Note: This question requires at least 6 sentences for a response in order to be eligible for full credit.

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