Safety Note
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In cases where special safety instructions are not given, use common safety precautions, especially when working with hot, sharp, or breakable items. Be sure to read and follow warning labels on household chemicals.
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Lesson List
Chromatographic Separation of Methylene Blue and Fluorescein
Chromatography Is a Gas: Inquiry-Based Introduction to Gas Chromatography
Drug Analysis Using Thin-Layer Chromatography
Gas Chromatography: Introduction and Application
HPLC Determination of Acetaminophen in an Analgesic
Innocent or Guilty: A Lab on DNA Gel Electrophoresis
Polyacrylamide Gel Electrophoresis (PAGE) of Egg Proteins
Polyacrylamide Slab Gel Electrophoresis of Proteins
Sample Preparation for Hand Lotion Analysis
Lesson Descriptions |
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| Chromatographic Separation of Methylene Blue and Fluorescein |
This lab has been modified from a common cookbook lab on column chromatography to be more of an inquiry-based lab on both thin-layer and column chromatography. The goal of the lab is to help students explore the roles of the stationary and mobile phases in chromatography. The students begin with a TLC lab in which they change the mobile phase and record the effects. They then do the same experiment using a column. The stationary phase is alumina (column) instead of silica gel (TLC). The students witness a reverse of the order in which the components are eluted. They must arrive at a hypothesis on why this happens. They are then given a real-life scenario problem in which they must figure out a method to separate methylene blue from fluorescein with fluorescein being eluted first. They must choose the correct stationary phase and mobile phase to obtain the desired separation.
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Chromatography Is a Gas: Inquiry-Based Introduction to Gas Chromatography
This chromatography exercise was designed to introduce students to the theory of chromatographic separation of mixtures and packed column chromatography. The students will become familiar with basic operation of the gas chromatograph and explore the relationship between temperature and retention time of individual components in a mixture. A section on instrument trouble-shooting may be included as an additional optional activity.
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Drug Analysis Using Thin-Layer Chromatography
The majority of evidence submitted to crime labs comes from drug-related crimes. Often, this evidence includes unidentified powders that may be illegal drugs. In order to prosecute individuals for possession of illegal substances, it is necessary for forensic scientists to positively identify any suspected drugs submitted to the laboratory. In addition, forensic toxicologists must determine the identity of drugs found in the bodies of drug-overdose victims. Although illegal substances can cause overdose, people also overdose on common over-the-counter (OTC) drugs, like aspirin, when attempting to take their own lives. Thin-layer chromatography (TLC) is one technique used to identify unknown drugs. Chromatography is simple to perform, is straightforward to interpret, and works equally well for legal and illegal substances. This experiment uses TLC to identify the active ingredients in some common OTC painkillers.
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Gas Chromatography: Introduction and Application
This laboratory exercise introduces students to gas chromatography using a discovery-based approach. The student is presented with a scenario/industrial application where their job is to verify that the company’s mouthwash contains a specific percentage of ethanol. They must discover that ethanol can be detected by gas chromatography and that peak height can be related to percentage of ethanol. This requires preparation of standard ethanol solutions. A batch of mouthwash is then suspected of isopropyl alcohol contamination and the student must develop a method to determine whether there is contamination. The technique of indirect determination by a standard addition method is introduced here.
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HPLC Determination of Acetaminophen in an Analgesic
High Performance Liquid Chromatography (HPLC) has resulted from the application of gas chromatography instrumental techniques to classical liquid chromatography. This experiment will utilize reverse phase chromatography with an octadecyl (C-18)column and a polar mobile phase consisting of methanol,acetonitrile,and water.
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Innocent or Guilty: A Lab on DNA Gel Electrophoresis
This lesson, based on EDVOTEK Kit #109, "DNA Fingerprinting I: Identification of DNA by Restriction Fragmentation Patterns," presents a simulation of a DNA fingerprint (RFLP—Restriction Fragment Length Polymorphism). The prelab section introduces the importance of DNA fingerprinting—a form of identification that is being accepted by both scientific and legal experts. The procedure is used in forensic work, paternity suits, missing-person cases, archeology, and animal breeding. The protocol for the lab is introduced. The lab involves students preparing a gel for electrophoresis. DNA fragments, which have been predigested using two different restriction enzymes, will be run on a gel electrophoresis apparatus, and the results will be analyzed to determine which suspect committed the crime. The post-lab section concentrates on the ethical implications of DNA fingerprinting.
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Polyacrylamide Gel Electrophoresis (PAGE) of Egg Proteins
Charged groups or ions will migrate in an electric field. Proteins carry a charge (except at their isoelectric point), and they too will migrate in an electric field with the rate of migration dependent upon the ratio of charge to mass. The application of an electric field to a mixture of proteins will result in different proteins moving at different rates within the field. In PAGE, a supporting medium (polyacrylamide) is used so that the proteins can be fixed in their final migration positions and analyzed.
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Polyacrylamide Slab Gel Electrophoresis of Proteins
Polyacrylamide gel electrophoresis (PAGE) is a powerful analytical technique used by biochemists and molecular and cell biologists to characterize and assay the purity of various biological macromolecules. The method is based on the principle that macromolecules can be separated according to their unique size and charge when placed in a gel matrix under an electrical field. In this experiment, the student will become familiar with one of the more popular versions; the sodium dodecyl sulfate (SDS) PAGE.
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Sample Preparation for Hand Lotion Analysis
In this experiment,students prepare a sample of a commercial hand lotion for analysis by HPLC to determine the percent composition of two common cosmetic preservatives,methylparaben and propylparaben.The product will be inspected for uniformity,standards will be prepared,the hand lotion sample will be prepared for analysis,the HPLC analysis will be performed,and the data will be evaluated.The significance and consequences of using syringe filters as a final sample purification step will be explored.In an optional pre-lab assignment,students are challenged to research their choice of syringe filter.