CHM121 chromatography

use the following chromatogram and table as your data. VWD: Sgrad A 284 nm Retention Time 40- -40 20 20 5 10 15 20 25 30 35 Minuteo VWD: Signal A, 284 nm Retention Area Identity Time (min) 7.867 3214697 Vitamin A 8.493 15687 19.410 140354 19.710 64346 20.803 884315 Vitamin E 21.640 36745 22.100 63054 8.403 L98 ÞI 20.803 ; 84年 81

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

As solvent polarity increases, the Retention Factor (Rf) of compounds on the TLC plate increases. Group of answer choices True False

2. What are mobile and Stationary phases in a chromatogram? Site their nature.

Use a suitable model to explain how separation and identification of a mixture of organic compounds can be achieved with a thin layer chromatographic (TLC) technique.

4) If the classification of the chromatography run is a reverse-phase chromatography, discuss the relative polarities of caffeine, aspartame and benzoate

4) If the classification of the chromatography run is a reverse-phase chromatography, discuss the relative polarities of caffeine, aspartame and benzoate.

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?

Question:  Using a sample of aspirin for HPLC analysis. If the aspirin was contaminated (wet) with trace amounts of a solvent such as ethyl acetate, hexane, or water, would this contaminant be detected and appear as a peak in the HPLC chromatogram? Briefly explain based on the type of detector used in HPLC analysis and what type of compounds can be detected. My Answer: The HPLC analysis detects chromophores, compounds with multiple double bonds. Since water, ethyl acetate, and hexane all lack multiple pi bonds this will not be detected in the HPLC.  -Question for you, is this complete (and correct), and should I include anything about UV detection? Is UV detection used in HPLC? I thought it was only used on TLC to show compunds that arent visable.

In the Thermo Fisher application note about wine analysis (Lesson 3), the following chromatogram was collected of nine components of wine. If peak 3 has a retention time of 3.15 minutes and a peak width of 0.070 minutes, and peak 4 has a retention time of 3.24 minutes and a peak width of 0.075 minutes, what is the resolution factor between the two peaks? [Hint: it will help to review Lesson 2 for this question.] mAU 300 200 100 0 3.22 0.62 1.04 1.24 2.4 2.6 2.8 LO 34 12 ww 3.0 5 3.2 3.4 3.6 3.8 4.0 Minutes 7 8 9 4.2 4.4 4.6 4.8 5.0 5.2

What is the Rf value given the following information: Height of Chromatography Paper: 5.0 cm Distance from Bottom of Paper to Origin: 1.5 cm Distance from Origin to Spot: 1.6 cm Distance from Origin to Solvent Front: 2.9 cm Your Answer: Answer

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?

A GC-MS was used to analyze an unknown sample. Based off the chromatogram, at least how many different compounds were in this sample? Detector Signal u M Retention Time

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

use the following chromatogram and table as your data.       What is the %composition of the Vitamin A peak in the sample?     78.43%        77.73%     7.867%       72.74%

Retention Time 40 20 25 Mntes VWD: Signal A, 284 nm Retention Area Identity Time (min) 7.867 3214697 Vitamin A 8.493 15687 19.410 140354 19.710 64346 20.803 884315 Vitamin E 21.640 36745 22.100 63054 What is the %composition of the Vitamin E peak in the sample? O 21.57% O 20.01% O 22.27% O 20.80% E8.403 89%花

I'm doing lab report for thin layer chromatography right now, but I'm struggling with a question about how the polarity affect separation. Please help me answer and explain it. Thank you so much!

Chemistry Briefly describe the differences between the scanning and SIM approaches with reference to your data. Discuss how and why your scanning (TIC) and SIM (mass chromatograms look different. Pay particular attention to selectivity of compounds detected and signal-to-noise. What are some advantages of SIM? What are some disadvantages?

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

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How does ammonia, dimethylglyoxime (DMG), and 8-hydroxyquinoline (8HQ) interact with your cations, leading to the evolution of colored species?   Context: Paper chromatography experiment (separation of inorganic cations) with a 9:1 acetone/ HCl solvent

Three students did a chromatography experiment, where Rf = distance of solute / distance of solvent. What could be the possible errors why student 3 had results that are quite far from that of students A and B?

Not exactly sure how to fill out the table?

Nonpolar aromatic compounds were separated by HPLC on a C18 column. The eluent was 65 vol% methanol in water, How would the retention times be affected if 90 vol% methanol was used instead? a) There is not enough information given to answer this question b) The retention times would be longer c) The retention times would be shorter d) The retention times would stay the same e) Depends on the structure of the nonpolar aromatic compound

1. An unknown food dye produced two spots on a chromatogram with Rf values of 0.35 and 0.08. Use the table below to identify the unknown compounds. 2. Which dye had the largest Rf value?  Which one had the smallest? Why?

3) What is the approximate retention time of benzoate?

A student 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 in the figure.  Determine the retention factor (Rf) values of each spot on dye C. (use 2 decimal places)  What other dye/s are present in dye C and what is the dye with least number of pigments?

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

A sample is going to be analyzed for trace amounts of ibuprofen using gas chromatography. Which of the following detectors would work best for the detection of ibuprofen? ibuprofen.png Group of answer choices alkali flame detector thermal conductivity detector flame ionization detector flame photometric detector sulfur chemiluminescence detector electron capture detector