CHM121 chromatography

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

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.

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 T 34 5 100- 1 2 CO 6 7 8 9 0 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4 4.6 4.8 5.0 5.2 Minutes 3.22 0.62 1.04 O 1.24

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?

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!

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!

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?

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

Peak Retention Time (minutes) Area 1.201 136501204 acetone 2.011 1253056 toluene ortho-product para-product 3.201 8340750 3.350 14890645 a) What was the relative percent yield of the ortho-product? b) What was the relative percent yield of the para-product? c) What was the relative percent yield of the product?

For what type of chromatography is there no stationary phase? a) HPLC b) GC c) size exclusion chromatography d) capillary electrophoresis e) ion exchange chromatography

Correlate the structures of the standard food dyes to their relative position in the paper chromatogram. Refer to the structures shown below. What are the identities of the unknowns in paper chromatography of food dyes? How did you arrive at this conclusion?

19. What is thin layer chromatography (TLC) LEAST useful for from the list below? A) To determine if crystallization or distillation may be more effective for a separation B) To determine the number of components in a mixture C) To determine the appropriate solvent for column- chromatographic separation D) To monitor the progress of an organic synthesis reaction 14. The solubility of salicylic acid in water is 7.8g/100ml at 100°C and 0.25g/100ml at 25°. Estimate how much water is needed to recrystallize a 19g sample of salicylic acid? A) 150ml B) 250ml C) 300ml D) 400ml

1) Which technique would be best to determine the amount of nitrate in drinking water? Select one. a) Electrophoresis b) UV Spectroscopy c) Reverse osmosis d) Ion Chromatography e) Atomic Absorption 2) Which technique would be best to quantitatively determine the concentration of a substance that absorbs light in the visible range? a) HPLC b) Spectroscopy c) PCR d) Ion chromatography e) Ultracentrifugation

Task: You are a forensic analyst employed at the Baltimore County Forensic Lab. You plan to perform paper chromatography on the ink from the note and a sample from the marker. Permanent marker ink is non-polar. You need to select the best solvent to use as the mobile phase in order to compare the ink sample and determine if they may be a match. The solvents you have available to you are carbon tetrachloride and water.Which solvent would be best to analyze the ink samples using paper chromotography?Your explanation should include:•    the name of the liquid solvent that should be used for the paper chromatography analysis•    scientific reasoning for your choice of the liquid solvent that will be used•    the Lewis structures for carbon tetrachloride, CCl4, and water, H2O•    how the shape and symmetry of each molecule influences its polarity