6th sub

The TLC plate is show below with pet ether-acetone mixture (3:1) as the mobile phase. Which spot is the most nonpolar? * O A O E 1O D MADE IN ENGLAND L wɔ 0 E.

You spotted a mixture of three compounds, labeled A-C, on a silica plate. The resulting thin layer chromatography (TLC) plate with a mobile solvent mixture of 95 % hexanes and 5 % ethyl acetate is shown below. Which of the spots traveled the furthest up the TLC plate corresponding to spot 3?

How do you calculate the retention factor (Rf) for each spot ? Distance traveled by spot O    5.5cm Distance traveled by spot Y    4.0cm Distance traveled by spot G    3.0cm  Distance traveled by solvent front    6.0cm

6. Say you are trying to separate two compounds by column chromatography. You run a column and collect the eluent in five fractions. You analyze each fraction by TLC on the same plate (shown below). Based on the TLC plate, how effective was your separation? -------1--- 1 2 3 4 5

Which of the following statements regarding thin layer chromatography are correct? O a. The larger a Rf of a compound, the larger distance it travels on TLC plate O b. When comparing two different compounds, the compound with the larger Rf is more polar O c. Larger Rf means compounds interact weaker with polar surface on the TLC O d. Polar compounds interact more strongly with polar surface of TLC and move faster e. a and b f. a and c

a. Say you are trying to separate two compounds by column chromatography. You run a column and collect the eluent in five fractions. You analyze each fraction by TLC on the same plate (shown below). Based on the TLC plate, how effective was your separation? Consider the purity of each fraction. - - - - - - - - ----| 1 2 3 4 5

please answer a,b,c,d

See image below

i need to caluclate a rf value for the tlc plate and i really need help with showing the steps please!   Reduction of 4-Nitrobenzaldehyde to 4-Nitrobenzyl Alcohol and Thin Layer Chromatography

A student used thin layer chromatography to confirm whether he could successfully separate two compounds. Here is the TLC plate he obtained after 30 min. Stationary phase was silica gel and mobile phase was 95 % ethyl acetate and 5 % Hexane mixture.

Qno1: why there is a need of chromatography and chromatography thecniqs. B) when and where we should use normal and reverse phase chromatography

Internal standard. A mixture containing 12.8 mM analyte (X) and 44.4 mM standard (S) gave chromatographic peak areas of 306 for X and 511 for S. A second solution containing an unknown quantity of X plus 55.5 mM S had peak areas of 251 for X and 563 for S. Find [X] in the second solution.

calculate Rfs for each spot on your chromatogram

(please answer all questions) 5-30. When marking the sample line on a TLC plate, why is it inadvisable to use a ball-point pen? 5-31. A series of dyes is separated by TLC. The data are given below. Calculate the Rf value for each dye. 5-32. Why is it important not to let the level of the elution solvent in a packed chromatographic column drop below thetop of the solid-phase adsorbent? 5-33. What are some advantages of using column chromatography to purify reaction products in the microscalelaboratory? 5-34. Discuss the similarities and dissimilarities of TLC, paper, and column chromatography. 5-35. Discuss the similarities and dissimilarities of HPLC and gas chromatography. 5-36. (a) What are the main advantages of using flash chromatography?(b) How can TLC be used in connection with flash chromatography? 5-37. Using the information presented on the right, please identify and explainwhich spot has an Rf value of 0.5.

Match column A with Column B. Everything is all about column Chromatography v Least polar molecules A. Eluate v most polar molecule B. eluted first the mobile phase C. silica v stationary phase D. eluted last molecules eluted together with the solvent E. Eluent v to removelextract/wash F. Elute

30. Can you explain explain liquid chromatographic separation.... And how to solve problems akin to this?

How can we answer

Study the chromatograph (below) of a mixture of Compounds A and B, run on the GCs in the teaching labs at CU Boulder. Compound A has the shorter retention time. You suspect that compound B is octane. What can you do to provide supporting evidence for this hypothesis?

So I completing a lab report and one of the sections is on TLC analysis. In the experiment, the TLC plate was submerged in toluene ethylacetate and had spots of cinnamon leaf oil, cinnamon aldehyde, and cinnamon bark oil. 9 spots total were seen under the UV light, but different spots appeared following a vanillin stain. Why is this so and what does this mean?

1) Aspirin 2) Acetaminophen 3) Ibuprofen 4) Caffeine

Why Rf value is important in Chromatography?  Please shortly answer at your own words. Answer should be the point (specific 4-5 lines).

I just need letter h please

Record your absorbance data for the YELLOW and RED dyes below. Calculate the dye concentration in mM for each cuvette using M1V2 = M2v2 . Remember the concentration of stock solutions (100^ % dye) is 0.020 mM(mM= millimolar =mm /L). Data for YELLOW: peak absorbance used on spectrophotometer =420nm Cuvette 1 - 100% dye = 0.680 absorption Cuvette 2 - 75% dye = 0.510 absorption Cuvette 3 - 50% dye = 0.340 absorption Cuvette 4 - 25% dye = 0.170 absorption Data for RED - peak absorption used on spectrophotometer = 500nm Cuvette 1 - 100% dye: 0.621 absorption Cuvette 2 - 75%: 0.466 absorption Cuvette 3 - 50% dye: 0.311 absorption Cuvette 4 - 25% dye: 0.1555 absorption

Answer sections C, D and E in the same answer book. Section D (Chromatography) Question 8 The following data were obtained for the analysis of a mixture of compounds (A-D) by HPLC: Peak Retention time (min) | Width of peak base (min) non-retained 2.1 A 6.4 10.51 B 11.3 1.03 C 13.1 1.25 D 21.6 1.62 a) Using peak C. calculate the number of plates (N) in this column. b) For peak D, calculate the capacity factor (k'). c) For peak B and C, calculate the resolution (R).

How can I calculate the concentration from a GC/MS chromatogram which is having retention time and peak area only?

A solution was prepared by mixing 12.49 mg of B plus 10.00 mL of unknown containing A and just diluting to 25.00 mL. Peak areas of 5.97 and 6.38 were observed for A and B, respectively. Find the concentration of A (mg/L) in the unknown.

HPLC VFA analysis - why do I get so different peaks for very similar samples?

Please find the Rf values of each drug and the name of the unknown sample!

When the use of 2D Thin layer Chromatography is better than normal TLC?  Please shortly answer at your own words. Answer should be to the point (specific 4-5 lines).

3 Compare: a) Capillary Electrophoresis with GC and HPLC. b) Separation Versus Preconcentration.

See image below

Q1) The chromatogram below show a separation of a mixture of 2 components injected in a 25-1cm column at a flow rate of 0.4 mlmin.Answer the following questions :a. Find the times that components A and B spend in the stationary phase.b. Find the retention times for A and B.c. Determine the retention factors for the two components.d. Find the full widths of each peak and the full width at half maximum values.e. Find the resolution of the two peaks.f. Find the average number of plates for the column.g. Find the average plate height.h. What column length would be needed to achieve a resolution of 1.75?i. What time would be required to achieve the resolution in part h.j. Assume that the column length is fixed at 25 cm and the packing material is fixed. Whatmeasurescould you take to increase the resolution to achieve baseline separation?k. Are there any measures you could use to achieve a better separation in a shorter time withthe samecolumn as in part j?

Olivia developed a new dye called Dye C. It was analyzed against other dyes using paper chromatography. A solution of 1:1 ethyl acetate:hexane was used as the eluent. The resulting chromatogram is shown below. 2 3 4 5 6 0 cm 1 A B C D E F G a. Determine the retention factor (Rf) values of each spot on dye C. Report your answer in 2 decimal places. b. What other dye/s are present in dye C? c. Which dye contains the least number of pigments?

Can you TYPE the definitions of the all of words please Chromatography TLC Stationary phase Mobile phase Elute Eluent Rf Value Elution chamber TLC “spotter”

1) Study the chromatograph (below) of a mixture of Compounds A and B, run on the GCs in the teaching labs at CU Boulder. Compound A has the shorter retention time. STAAT 61 1.11 227 RT TYPE AREA XXXX XXXX XXXX AREAS 0.009 55874 44.117 ARIHT 0.61 XX XX XX 1.11 2.27 XX XX XX TOTAL AREA=XX MUL FACTOR=XX 1. What is the retention time of compound A? Compound B? 2. Which compound is present in a larger amount? 3. Which compound has the lower boiling point? 4. What would happen to the retention times of compounds A and B if the column temperature were raised? 5. You suspect that compound B is octane. What can you do to provide supporting evidence for this hypothesis?

How can you use ion exchange Chromatography to de-ionize water?  Please shortly answer at your own words. Answer should be to the point (specific 4-5 lines).