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Paper Chromatography CHEM 221-02 October 31, 2019 Meghan Tillger Dr. Fealy

Abstract: Paper chromatography was performed with three duplicate chromatograms of six dyes (B1, B2, Y5, Y6, R3, R40) and evaluated under different solvent systems: H2O, .1% isopropanol, and 70 % NaCl. Each of these duplicate chromatograms were tested for the separation efficiency and it was proven that NaCl was the best solvent. Because NaCl was the best solvent, it was used to identify other unknown dyes.

Introduction: Paper chromatography is a method to analyze a separation of molecules into their own apparatuses, which aids in identifying compounds. This is possible due to the capillary attractions formed from cohesion and adhesion in the transition from stationary phases to mobile phases. Depending on which compounds are used, the solvent’s efficiency in separating the mixture may be different as well. The best solvent result tested will allow for this process to be more efficient. If H2O, .1% isopropanol, and 70% NaCl are tested as solvents for paper chromatography, then H2O will result as the best solvent because of its polar covalent bonds that allow for better cohesion and adhesion.

Procedure: 1. The first step was to mark each of your chromatography papers with pencil 1.00 cm from the bottom and 1.00 cm from the top. You then made mark 1.50 cm in from side with a distance of about 1.00cm in between each mark. There would be 10 marks. You repeated this step 5 times. 2. You then labeled your spots using pencil.

3. You took each sample and a different toothpick for each one and spotted the mark on the paper with the sample two times and 4 times for B2. 4. You repeated the step above for each of the chromatography paper, the only one that was different was #4 and #5. 5. You then placed each paper that went with the different solutions into the solutions and placed the lid on top. The different solutions were H2O, Iso-propyl alcohol and NaCl. 6. Once the solution reached the top line you created you removed them from the containers and placed them on paper towel to dry. 7. Then you placed the paper with the unknown samples into the solution you thought was the best and waited for the solution to reach the top of the paper. Once that happened you removed the paper and set it on a paper towel to dry. 8. The 5 and final paper was a “fun” paper, you placed your spots wherever you wanted and placed it in a solution to see what would happen. Results: Salt Water

Average ST Deviatio n

B-1

B-2

Y-5

Y-6

.947 .263 U:.965 U:.298

.702 .438 U:.614 U:.526

.956 .009

.658 .044

Water

Average ST

.281 .0175

B-1 B-2 1.02 N/A U:.965 U:.29 8 .992 .0275

.482 .044

Y-5 1.02 U:.61 4 .817 .203

R-3

R-40

B1/R40

B1/Y5

B2/Y6

B2/Y5

.052 U:.08 8 .07 .018

.228 U:.24 5 .236 .0085

B1:.877 R40:.22 8 X .325

B1:.898 Y5:.702

B3:.088 Y6:.438

B2:.263 Y5:.702

X .098

X .175

X .2195

Y-6 R-3 .965 .578 U:.526 U:.08 8 .745 .333 .2195 .245

R-40 B1/R40 B1/Y5 B2/Y6 B2/Y5 .965 B1:1.09 B1:1.08 B3:.526 B2:.929 U:.088 R40:.965 Y5: Y6:.965 Y5:0 .526 .438

X .0625

X

X .2195

X .4645

Deviatio n Isopropyl B-1 Alcohol 1.05 U:.96 5 Average ST Deviatio n

1.01 .0425

B-2

Y-5

Y-6

R-3

R-40

B1/R40 B1/Y5

B2/Y6

.965 U:.29 8

1.02 U:.61 4

0 U:.52 6

.929 U:.08 8

0 U:.08 8

.631 .3335

.817 .203

.263 .263

.508 .4205

.044 .044

B1:1.0 7 R40: . 929 X .0705

X .0615

Relative Average Error:

Conclusion:

B2/Y5

B1:1.05 B3:.947 B2:.912 Y5:1.0 Y6:1.0 Y5:1.0 2 7 2 X .015

X .054

It was proven that many “unknown dyes” are mixtures of the six common dyes mentioned above. The best solvent for the lab that was the salt water mixture. That showed the most movement out of the three and it was the fastest to reach the top of the paper. From the looks of the unknowns on the paper PC Unknown 34 looks as if it is R-40 with the coloring and the distance it traveled. Unknown #6 showed light blue and pinkish color which looked the same as the B1/R40 mixture so that is what I am leaning towards for that one. And lastly the PC Unknown 41 did not really show any color so I am not exactly sure what that one could have been....