Experiment 5- TLC

Column Chromatography Alumina Chromatography Mixture 9:1 Hexanes:Ether 8:2 Hexanes:Ether 1:1 Hexanes:Acetone Amount Used 3.962 g 0.143 g 9.50 mL 9.50 mL 11.00 mL Additional Observations (Color, etc.) BIU X₂ X² → BI IU X₂ X² → BI IU X₂ X² → BI IU X₂ X² → BIU X₂ X² →

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.

anch of the following components cannot be detected by gas chromatography? 4 Essential oils Alcohols b) Volatile compounds d) Non-volatile compounds 13- is measured as time elapsed from the point of injection to the peak maximum? a)-Column efficiency d)- Delectability c)-Retention time 14- Which of the following can be used to detect the components in gas chromatography a) non-volatile compounds b) volatile compounds c) Salts d) b&c 15-Which of the following methods is often referred to as mechanical separation processes. a)-Gas Chromatography b)-column chromatography c)- Sedimentation 16- For obtaining better resolution in TLC. and then developed with a second solvent at right angles to the first a) Stepwise b) Descending e) Ascending 17- This is defined as transport of electrically charged particles in a direct-current electric field a) ion exchange chromatography b) Electrophoresis c) ultracentrifuge d) exclusion 18-This figure indicates to schematic Diagram of a) Gas chromatography…

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

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

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%

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

How can you use ion exchange Chromatography to de-ionize water? Please shortly write at your own words. (4-5 lines maximum ).

In molecular exclusion (size exclusion) chromatography, the molecules have the longest retention times. a) the larger molecules b) the smaller molecules

The uses of thin layer chromatography are: 1) To identify unknown compounds 2) Determine purity of products 3) Analyze reaction mixtures 4) To waste time in lab 5) Determine the melting point of the product U 6) Put an astronaut on the moon.

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?

Use the following information collected from a SIZE-EXCLUSION CHROMATOGRAPHY experiment to  answer the questions below.  MW Standards  Molecular Weight (kDa)  Elution Volume (mL) blue dextran  1000  85 myoglobin  17.2  200 TIM  53.3  178 hemoglobin  62.2  156 IgG  140  122 ATCase  307.9  94 Prepare a graph showing the linear relationship between log function of molecular weight against  Ve/Vo. The R2value must be 0.9 or higher. What is the linear equation from the standards given? What is  the R2value?

1a) Hexane, CH3(CH2)4CH3, is found to have a long retention time when separated from a mixture. A column with a C18 (18-carbon chain) stationary phase and a methanol-water modal phase is used for the separation. Explain why hexane has a long retention time. 1b)You wish to chromatographically seperate a mixtureof the follwing compunds. Which of the two compounds will be most difficult to seperatate from one another? Why?

A young researcher set out to develop a method for quantifying the polycyclic aromatic hydrocarbon (PAH) content in a contaminated soil sample using open tubular gas chromatography. During the initial stages of method development, the researcher was unable to separate the early eluting compounds, anthracene and naphthalene, with baseline resolution. Select the possible modifications the researcher could make to improve the resolution. use a column with a smaller inner diameter decrease the column length increase the stationary phase thickness increase the temperature choose a different stationary phase

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

The following data are from the HPLC assay of paracetamol 500 mg tablets using the calibration curve method: - Weight of active ingredient in powdered tablets taken for analysis: 180 mg • Initial extraction volume: 200 mL - Dilution steps: 10 mL into 100 mL, then 5 mL into 100 mL - Linear equation: y = 12000x - 50 %3! - Area of chromatographic peak for sample is 4750. What is the theoretical concentration in final solution in mg/100 mL? (2 decimal places). Please do not write the units, just numerical value. Answer: