《Paper Chromatography.doc》由会员分享，可在线阅读，更多相关《Paper Chromatography.doc（20页珍藏版）》请在三一办公上搜索。
1、1. Introduction Page 12. TerminologyPage 23.ExperimentPage 3What Color is that Sharpie?4.Alternative ExperimentsPage 9Water Soluble vs. PermanentAlcohol vs. AlcoholPaper vs. PaperFood ColorsFlower PigmentsKool-Aid Food DyesMystery Sample5.Hints, Tips, and ExtrasPage 15Sabrina SchmidtkeProtein Chemis
2、try LaboratoryTexas A&M UniversityPaper Chromatography: IntroductionChromatography is a technique for separating mixtures into the components that they are made from in order to analyze, identify, quantify, or purify the mixture or components.A scientist will use chromatography to: examine a mixture
3、, its components, and their relations to one another (analyze) determine the identity of a mixture or components based on known components (identify) separate components in order to isolate one of interest for further study (purify) determine the amount of the mixture and/or the components present i
4、n the sample (quantify)Real life examples of uses for chromatography include: pharmaceutical companies determining the amounts of each chemical found in a new product hospitals detecting drug or alcohol levels in a patients blood stream law enforcement agencies comparing a sample found at a crime sc
5、ene to samples from suspects environmental agencies determining the level of pollutants in the water supply manufacturing plants purifying a chemical needed to make a productDifferent types of chromatography are used: liquid chromatography, gas chromatography, paper chromatography, and thin-layer ch
6、romatography. While each type of chromatography uses different methods to separate compounds, they all share the same principles. Chromatography utilizes the differential affinities of the components for a gas or liquid mobile medium (mobile phase) and for a stationary adsorbing medium (stationary p
7、hase) through which they pass. The stationary phase holds the mixture until the mobile phase passes through, solubilizes the components, and moves them along at their individual rates. Once components are separated from one another, they can be analyzed.In paper chromatography the stationary phase i
8、s the filter paper and the mobile phase is the solvent. The filter paper holds the components until the solvent dissolves them and carries them up the filter paper. The solvent travels up the filter paper by capillary action. The solvents attraction to itself pulling it up is greater than the force
9、of gravity pulling it down. The separation of components depends on their solubility with the solvent and their affinity to the solvent and filter paper. The solvent can only move the components if they are soluble in it and the more soluble a component is the more there is available to move up the
10、filter paper. Solutes will dissolve into solvents that have similar properties. Polar solvents dissolve polar solutes and non-polar solvents dissolve non-polar solutes. (Like dissolves like.) A component will travel up the filter paper at a rate that is determined by its affinity to the filter paper
11、 and solvent. Since each component has its own solubility with the solvent and its own affinity to the solvent and filter paper, they can be separated in multiple ways by using mixtures of different solvents and different filter papers.Page 1Paper Chromatography: TerminologyAffinity natural attracti
12、on or force between things.Capillary Action the movement of liquid within the spaces of a porous material due to the forces of adhesion, cohesion, and surface tension.Chromatogram the graphic record produced by chromatography. Chromatography a laboratory technique that separates components within a
13、compound by utilizing the differential affinities of the components for a gas or liquid mobile medium and for a stationary adsorbing medium through which they pass.Component a constituent element or part.Differential showing a difference, distinctive.Mixture a material composed of two or more elemen
14、ts or parts.Mobile Medium gas or liquid that carries the components (mobile phase).Solubility the quality, condition, or degree of being soluble or solvable.Solute a substance that is dissolved in another substance to form a solution.Solution a mixture of a solvent and a solute.Solvent a substance t
15、hat dissolves other substances to form a solution. Stationary Medium the part of the apparatus that does not move with the sample (stationary phase).Page 2Paper Chromatography: ExperimentWhat Color is that Sharpie?PurposeTo introduce students to the terminology and principles of chromatography and d
16、emonstrate separation of the dyes in Sharpie Pens with paper chromatography.Time Requiredq Preparatory time 10 minutesq Experiment time 45 minutes Costsq Less than $10Materials Listq 6 beakers or clear jars/cupsq 6 covers or lids (tinfoil is sufficient)q Distilled H2Oq 100% isopropanol or 70% isopro
17、panol (rubbing alcohol)q 10 ml graduated cylinderq 6 strips of filter paperq Different colored Sharpie pensq Pencilq Rulerq Scissors q TapePrepare the Isopropanol Solutionsq Label the beakers with the following: 0%, 5%, 10%, 20%, 50%, and 100%. q Using the 100% isopropanol and distilled H2O, make th
18、e following isopropanol solutions: 0%, 5%, 10%, 20%, 50%, and 100%. Isopropanol Solutions for Paper Chromatography0%5%10%20%50%100%Isopropanol 100%0 ml7.5 ml of 10%*2.5 ml3 ml7.5 ml15 mlDistilled H2O15 ml7.5 ml22.5 ml12 ml7.5 ml0 mlTotal Volume15 ml15 ml25 ml15 ml15 ml15 ml* Use 7.5 ml of the 10% is
19、opropanol solution and 7.5 ml of H2O to make the 5%.Page 3Paper Chromatography: Experiment cont.* When using 70% ispropanol instead of 100%, an adjustment is made in making the 50% *Isopropanol Solutions for Paper Chromatography0%5%10%20%50%70%Isopropanol 70%0 ml7.5 ml of 10%11.25 ml of 20%10.5 ml20
20、 ml 15 ml Distilled H2O15 ml7.5 ml11.25 ml15.75 ml8 ml0 mlTotal Volume15 ml15 ml15 ml15 ml28 ml15 mlq Pour each of these solutions into their labeled beakers just enough to cover the bottom. Cover them immediately because the isopropanol will evaporate. Prepare the Chromatography Stripsq Cut the fil
21、ter paper into 6 strips that are about 5 cm x 8 cm. If the beakers are tall enough you can make the strips longer to allow for more separation. The longer the strips are the longer it will take to develop them. q Draw a line lightly with the pencil across the strips 1 cm above the bottom edge. q Lab
22、el the strip with the corresponding solution that it will be placed in. q Spot each Sharpie pen on the starting line. For better results spot a pen, let it dry and spot it again on top of the first spot. Keep the spots small and space them out as much as possible so that the colors will not run toge
23、ther as they separate. Page 4Paper Chromatography: Experiment cont.Developing the Chromatogramsq Place the strips in the beakers. Make sure the solution does not come above the starting line. If you need to, remove some of the solution. If you use a thin filter paper you may need to support the stri
24、ps to keep them from sliding down into the solution as they get wet. Depending on the type of cover used for your beakers, you can either tape the top of the strip to a pencil sitting on top of the beaker or tape the strip to the sides of the beaker. q Cover the beakers and let the strips develop un
25、til the ascending solution front is about 2 cm from the top of the strip. q Remove the strips and let them dry on a paper towel. q Dispose of the isopropanol solutions down the drain with large amounts of water.Observing the Chromatogramsq Look at the chromatograms and observe: How the spots of dye
26、separated in low concentrations of isopropanol compared to higher concentrations? What colors are each of the dyes made of? In what concentration did the dye of each color start to move and in what concentration had all of the dye from each color moved from the starting line?q Results: Black- dye se
27、parated into purple and black- dye is not soluble in water- dye is partially soluble in concentrations of isopropanol 20%, but does not fully solubilized in 100% isopropanol Green - dye separated into blue and yellow- yellow dye is soluble in isopropanol concentrations 0% - blue dye is less soluble
28、than the yellow, but is completely soluble in 100% isopropanol Blue - dye separated into blue- dye is not very soluble in water- dye is completely soluble in 100% isopropanolPage 5Paper Chromatography: Experiment cont. Red - dye separated into red and yellow- yellow dye is water soluble and shows up
29、 at the top of the 10% and 20% chromatograms, it travels less in the 50% and even less in the 100% because of the increasing isopropanol concentrations- red dye is not very soluble in water and is completely soluble in isopropanol concentrations 20%q Even though all of the dyes are soluble in isopro
30、panol, the different colored pens started to separate at different concentrations of isopropanol. Each color has a slightly different solubility with isopropanol. 0% Isopropanol 5% Isopropanol 10% Isopropanol 20% Isopropanol 50% Isopropanol 100% IsopropanolPage 6Paper Chromatography: Experiment cont
31、.QuestionsBefore Experiment1. What is isopropanol commonly used for?2. Are there any safety precautions that should be taken with isopropanol?3. What colors do you think each pen dye will have?4. Which solution do you think will separate the dyes the best?After Experiment5. What color does each pen
32、dye contain?6. When did each pen start to solubilize in the isopropanol?7. Why does some of the black dye not move?8. Why does the yellow dye move farther than the red dye in the 10% and 20% isopropanol solutions and the red dye move farther than the yellow dye in the 50% and 100% isopropanol soluti
33、ons?9. Are the blue dyes in the blue pen and the green pen the same? How about the yellow dyes in the red pen and the green pen? How do you know?10. Which pen color would be the easiest to wash off your skin with isopropanol? Which would be the hardest to wash off? Why?AnswersBefore Experiment1. Iso
34、propanol is a common disinfectant and skin antiseptic.2. You should not inhale, ingest, or come into contact with the isopropanol because it can be harmful in some cases. Isopropanol is flammable, do not ignite it.3. Students Predictions.4. Students Predictions.After Experiment5. Black purple and bl
35、ack, Blue blue, Green yellow and blue, Red yellow and red.6. Black 50% isopropanol, Blue 20% isopropanol, Green 20% isopropanol, Red 0% isopropanol.7. Some of the black dye is not soluble in isopropanol or in water, so it cannot travel up the filter paper with the solvent.8. The yellow dye is more s
36、oluble in water than the red dye. That is why it moves in low concentrations of isopropanol. The red dye is more soluble in isopropanol than the yellow dye. That is why it moves in high concentrations of isopropanol.9. If the dyes were the same, we would expect the color to be the same and for the d
37、yes to travel the same way in the different solutions. The blue dyes in the blue and green pens Page 7Paper Chromatography: Experiment cont.are not the same. We know this because the color of blue on the chromatograms are different and because the blue dye from the blue pen starts to move up the fil
38、ter paper in a different solution than the blue dye in the green pen. The yellow dyes in the red and green pens are not the same. We know this because the yellow dye in the green pen is more soluble in isopropanol than water. The yellow dye in the red pen is less soluble in isopropanol than water. T
39、he yellow dyes are found in different positions on the chromatograms.10. The red pen would be the easiest to wash off because it is more soluble in isopropanol than the other pens. Look at the 50% isopropanol chromaotogram. There is only a little of the red left at the starting line, while there is
40、still a lot of the other colors. The black pen would be the hardest to wash off because some of the black dye is not soluble in isopropanol. That part of the black dye would stay on your skin and not wash off with just isopropanol.Page 8Paper Chromatography: Alternative Experiments Water Soluble vs.
41、 Permanentq Purpose to compare the solubility of different types of markers in water and isopropanol.q Additional Materials several water soluble markers (washable markers, felt tip pens, ink pens, and highlighters) and several permanent markers. Markers can be different colors or all the same color
42、 as long as they are different brands.q Make the isopropanol solutions as described in the Sharpie experiment. q Prepare the strips and spot them with the water soluble markers and permanent markers as described in the Sharpie experiment.q Develop the strips until the solvent is about 2 cm from the
43、top of the strip.q After developing the strips, you should be able to determine which markers are water soluble and which are permanent.Alcohol vs. Alcoholq Purpose to determine what alcohol separates permanent markers the best.q Additional Materials different types of alcohols including methanol, e
44、thanol, propanol, isopropanol, and/or butanol. WARNING: Be very careful when working with these solvents. Some can be dangerous if not handled properly.q Instead of using different concentrations of each alcohol, use the same concentration of each to separate the spots of permanent markers.q Prepare
45、 the strips and spot them as described in the Sharpie experiment.q Develop the strips until the solvent is about 2 cm from the top of the strip.q After developing the strips, you should be able to determine if the type of alcohol used as the solvent makes a difference in separating the permanent markers.Page 9Paper Chromatography: Alternative Experiments cont.Paper vs. Paperq Purpose to test different type of paper to compare their separation capabilities.q Additional Materials d
