CHM 3430L Cal Poly Pomona Chemistry Non volatile GC Sample Treatment Lab

  • Butter Flavored Popcorn on Rt-2560
    Time (min)
    Methyl myristate
    Methyl palmitate
    Methyl stearate
    Methyl oleate
    Methyl vaccenate
    Methyl linoleate
    Methyl linolenate
    Inj. Vol.:
    Inj. Temp.:
    Oven Temp.:
    Carrier Gas
    Flow Rate:
    © 2018 Restek Corporation. All rights reserved.
    tR (min)
    C18:1 cis-9
    C18:1 cis-11
    C18:2 cis-9,12
    C18:3 cis-9,12,15
    Rt-2560, 100 m, 0.25 mm ID, 0.20 µm (cat.# 13198)
    Butter flavored popcorn
    1 µL split (split ratio 100:1)
    Topaz 4 mm ID straight inlet liner w/wool (cat.# 23300)
    250 °C
    160 °C to 250 °C at 2 °C/min (hold 5 min)
    H2, constant flow
    2 mL/min
    FID @ 250 °C
    Agilent 7890A GC
    The sample was prepared using sodium methoxide.
    Restek patents and trademarks are the property of Restek Corporation. (See for full list.) Other trademarks in Restek literature
    or on its website are the property of their respective owners. Restek registered trademarks are registered in the U.S. and may also be registered in other countries.
    CHM 3430L Unit #3
    Non-volatile GC Sample Treatment
    One of the most important requirements for GC analyses is that samples for GC analyses
    must be volatile. Not all samples, such as fats and organometallic compounds, however, are
    volatile. Derivatization, which is the process of chemically modifying a species to produce a new
    species which has properties more suitable for analysis, is needed for these non-volatile species.
    Section A. Transesterification of Fatty Acids
    Fats, known as “lipids” in technical term, constitute a major class of biological substances
    that include fatty acids, their naturally occurring compounds, and other substances related to them
    chemically. The simple lipids are esters of various long-chain fatty acids with glycerol. Lipids
    are the fundamental constituents of all biological cell membranes and provide a major portion of
    our caloric intake. Consequently, their accurate characterization is of considerable importance to
    several branches of science and industry.
    The most widely accepted method for the GC analysis of non-volatile lipids involves their
    conversion to the volatile methyl esters of the fatty acids, followed by gas chromatographic
    separation and identification on the basis of their relative retentions under specific
    chromatographic conditions.
    Question 1. The most widely accepted method for converting non-volatile lipids is through
    conversion reaction which produces volatile methyl esters, shown below. This reaction is called
    Question 2. The reaction vessel contains excess lipids, methanol, sodium methoxide, produced
    methyl esters, and glycerol. An aqueous extraction must be performed, following the above
    reaction. Why?
    Question 3. The aqueous extraction will produce two immiscible layers. Why is this happening?
    Question 4. Which layer, organic or aqueous, should be injected into the GC?
    Question 5. In this experiment, the content of myristic (C14:0), palmitic (C16:0), stearic (C18:0),
    oleic (C18:1), linoleic (C18:2), and linolenic (C18:3) in a sample of a fat (unknown) will be
    determined. What do the numbers in each parenthesis stand for?
    Wet Experiment Procedure
    1. Check out the prepared set of standard solutions of each ester (~10 mg/mL; from the
    stockroom). Carefully read the labels on the bottle and do NOT mix the standards.
    2. Inject 0.5 µL of each fatty acid methyl ester (FAME) standard (including methyl myristate,
    methyl palmitate, methyl stearate, methyl oleate, methyl linoleate, and methyl linolenate;
    each ~10 mg/mL) by the air sandwich technique to establish its retention time for
    identification. To save time, run two standards simultaneously. Draw 1 µL of air, 0.5 µL
    of FAME standard #1, 1 µL of air and 0.5 µL of FAME standard #2 into the syringe.
    3. Obtain your unknown sample and weigh out ̴ 25 mg (1 drop) of it into a screw-capped vial.
    4. Perform the transesterification: pipet in 1 mL of methyl tertiary-butyl ether (MTBE) and
    add 100 µL of a 25% sodium methoxide solution in methanol. Cap the vial and shake it
    occasionally for one or two minutes, then allow it to set for five minutes. Perform the
    extraction: add about 1 ml of water to the vial and shake, then allow the top ether layer to
    separate. Centrifuge if layer separation is slow.
    5. Carefully withdraw enough of the upper layer with a plastic eyedropper and transfer it to
    a 1 mL screw-capped vial. Be careful to withdraw only the upper layer.
    6. Inject exactly 1.0 µL of the extract by the air sandwich technique and start the GC run.
    Unit 3 Assignment 1
    Please see Canvas Module 3 L3P1 Assignment for details.
    Section 2. Organometallic Compounds
    With the rapid growth in industry, more and more organometallic compounds are found
    in the environment we all live. The toxicity and mobility that these compounds have raise a great
    concern to environmental chemists. The most important and abundant organometallic
    compounds that are present in the environment are organomercury, organolead and organotin
    species. Although, classically, those compounds are analyzed via inductively coupled plasma
    (ICP) MS or atomic absorption spectroscopy, GC–MS is a powerful tool for organometallic
    compound analysis. Similar to fatty acid analysis, organometallics must be derivatized to form
    volatile or semi-volatile compounds via ethylation or phenylation. Solid phase microextraction
    (SPME) is often used to facilitate the extraction and injection of organometallic derivatives.
    Question 1. A small volume of volatile compound (in the liquid form) is pipetted in a glass vial
    and capped. What is going to happen next?
    Question 2. Sometimes it is necessary to sample the vapor to avoid the impurities in the sample.
    A SPME needle is thus developed. As indicated on the diagram of the needle, which part is
    responsible for sample extraction?
    Question 3. What determines the amount of analyte being absorbed on the fiber?
    Question 4. Should a thin coating or thick coating be used on the fused-silica fiber?
    Question 5. How can you enhance the extraction efficiency of analyte from the liquid?
    Question 6. The figure below indicates the extraction and injection of sample through SPME.
    Following the extraction of analyte onto the fiber in the headspace, the fiber inside the SPME needle
    is introduced into the injector port. The high temperature at the injection port quickly remove the
    analytes from the coating. GC separation of the analytes is hence started. If a trace amount of
    organometallic (

      Don't use plagiarized sources. Get Your Custom Essay on
      CHM 3430L Cal Poly Pomona Chemistry Non volatile GC Sample Treatment Lab
      Just from $13/Page
      Order Essay
      Achiever Essays
      Calculate your paper price
      Pages (550 words)
      Approximate price: -

      Why Work with Us

      Top Quality and Well-Researched Papers

      We always make sure that writers follow all your instructions precisely. You can choose your academic level: high school, college/university or professional, and we will assign a writer who has a respective degree.

      Professional and Experienced Academic Writers

      We have a team of professional writers with experience in academic and business writing. Many are native speakers and able to perform any task for which you need help.

      Free Unlimited Revisions

      If you think we missed something, send your order for a free revision. You have 10 days to submit the order for review after you have received the final document. You can do this yourself after logging into your personal account or by contacting our support.

      Prompt Delivery and 100% Money-Back-Guarantee

      All papers are always delivered on time. In case we need more time to master your paper, we may contact you regarding the deadline extension. In case you cannot provide us with more time, a 100% refund is guaranteed.

      Original & Confidential

      We use several writing tools checks to ensure that all documents you receive are free from plagiarism. Our editors carefully review all quotations in the text. We also promise maximum confidentiality in all of our services.

      24/7 Customer Support

      Our support agents are available 24 hours a day 7 days a week and committed to providing you with the best customer experience. Get in touch whenever you need any assistance.

      Try it now!

      Calculate the price of your order

      Total price:

      How it works?

      Follow these simple steps to get your paper done

      Place your order

      Fill in the order form and provide all details of your assignment.

      Proceed with the payment

      Choose the payment system that suits you most.

      Receive the final file

      Once your paper is ready, we will email it to you.

      Our Services

      No need to work on your paper at night. Sleep tight, we will cover your back. We offer all kinds of writing services.


      Essay Writing Service

      No matter what kind of academic paper you need and how urgent you need it, you are welcome to choose your academic level and the type of your paper at an affordable price. We take care of all your paper needs and give a 24/7 customer care support system.


      Admission Essays & Business Writing Help

      An admission essay is an essay or other written statement by a candidate, often a potential student enrolling in a college, university, or graduate school. You can be rest assurred that through our service we will write the best admission essay for you.


      Editing Support

      Our academic writers and editors make the necessary changes to your paper so that it is polished. We also format your document by correctly quoting the sources and creating reference lists in the formats APA, Harvard, MLA, Chicago / Turabian.


      Revision Support

      If you think your paper could be improved, you can request a review. In this case, your paper will be checked by the writer or assigned to an editor. You can use this option as many times as you see fit. This is free because we want you to be completely satisfied with the service offered.

      Live Chat+1(978) 822-0999EmailWhatsApp

      Order your essay today and save 20% with the discount code RESEARCH

      slot online