lecture32008 - - OOC N N SO3- - O3S N N OH Separation and...

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Separation and Identification of Separation and Identification of Food Dyes by Food Dyes by (100 points) ELUATE BAND 2 BAND 1 N N N N - O 3 S OH - OOC SO 3 -
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Chromatography and Popular Entertainment
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Lab Expectations Lab Expectations 1. Read Exercise and other assigned readings 1.Attempt Pre-lab exercise Seek help in help room if necessary 3. Attend pre-lab lecture Turn in Pre-lab exercise 4. Attend Laboratory Perform Exercise recording activities in lab notebook Transcribe final data onto data sheets Turn in data sheet with execution plan Lab Expectations
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What is the quantitative basis for chromatographic separation What experimental conditions optimize chromatographic separation? What properties of substances can be used as a basis for their separation? ? QUESTIONS & CONCEPTS ? With what accuracy can you identify the components of a mixture of food dyes by paper chromatography? Questions
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Concepts: chromatography mobile phase migration rate stationary phase solvent front resolution retention factor capillary action solvents Techniques: Preparing a chromatogram optimizing resolution measuring spots Apparatus: solvent chamber (beaker/watch glass) ruler chromatogram
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Chromatographic separation involves TWO PHASES , (i.e., states of matter). MOBILE PHASE (gas or liquid) BACKGROUND STATIONARY PHASE (liquid or solid) Technique has been developed in many different ways: In this exercise: The mobile phase passes through the sample by CAPILLARY ACTION in the paper MOBILE PHASE = Solvents (H 2 O, etc.) STATIONARY PHASE = Chromatography paper ELUATE BAND 2 BAND 1 Column, gas phase, gel, paper, etc. Background
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CAPILLARY ACTION: Spontaneous rising or lowering of a liquid level in a narrow tube COHESIVE FORCES ADHESIVE FORCES and Those that keep a liquid together and try to minimize its surface area Forces of attraction (or repulsion) between a liquid and its container Caused by a BALANCE BETWEEN Capillary Action
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Consider the behaviors of Water and Consider the behaviors of Water and Mercury with respect to Glass Mercury with respect to Glass Adhesive > Cohesive Cohesive > Adhesive Chromatography paper can be thought of as having a very large number of very small capillary channels in each of which the liquid rises Glass Tube Hg Water & Hg
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How does chromatographic separation work? QUALITATIVELY: The interactions can be based on: Therefore, DIFFERENT SUBSTANCES generally have DIFFERENT INTERACTIONS Solute = Dye Paper Solvents Different solute molecules interact differently with the stationary phase and with various mobile phases Molecular size Electrical Charge etc. Solubility
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This note was uploaded on 09/21/2009 for the course CHE 143 taught by Professor Raleigh during the Fall '09 term at SUNY Stony Brook.

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lecture32008 - - OOC N N SO3- - O3S N N OH Separation and...

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