Lab 2- TLC

Earth, a CHEM 40.1 student, extracted a mixture of pigments from the roots of Rubiatinctorum, commonly known as rose madder. Earth spotted the root extract on twohydrophobic silica gel plates. He then placed each plate in separate developing chambers,one containing solvent system WHITE and the other housing solvent system MIX. Earthallowed the chromatograms to develop for around five minutes. Afterwards, he removedthe plates from the containers and placed them inside an iodine chamber. Thechromatograms resulting from the TLC experiment after visualization are illustrated asfollows. The distances travelled by each spot and by the solvents were measured andrecorded in the displayed table.

1. For the following chromatography state what the mobile phase is, stationary phase is, and what would elute first for each of the chromatography type... HPLC Gas Chromatography Ion Exchange Chromatography Size Exclusion Chromatography (SEC) Affinity Chromatography Reverse Phase Chromatography Normal Phase Chromatography

Please answer Questions 5-3, 5-4, and 5-5 (GC Gas Chromatography) 5-2. A sample mixture of ethyl benzoate (bp 212 Celsius) and dodecane (bp 216.2 Celsius) is injected on two GC columns.Column A has DC710 silicone oil as the stationary phase, and column B uses polyethylene glycol as the stationaryphase. Which substance would be certain to elute first from column A and would the same material be expected toelute first from column B? Which column, A or B, would be expected to give the better separation of these two substances? 5-3. Question 5-2 refers to separating a mixture of two high boiling liquids by gas chromatography. These materials havesimilar boiling points. List several GC variables and conditions that would make it easier to separate thesesubstances by gas chromatography. 5-4. Capillary GC columns have better resolution than packed columns even though the enormous surface area provided by the packing material is absent in capillary columns. Why? 5-5. Preparative GC requires…

what are key reactions involved in seperation of liquid mixtures by simple and fractional distillation and gas chromatography? chemicals used: 10ml 1:1 mixture of ethyl and butyl acetate techniques: simple and fractional distillation, gas chromatography. target molecules: Ethyl acetate C4H8O2           Butyl acetate C6H12O2

Thin‑layer chromatography (TLC) can be used as a preliminary identification method for many amphetamine‑type stimulants (ATS). Using a 0.25 mm thick silica gel stationary phase and a 98.5:1.5 methanol:concentrated ammonia mobile phase, a spot was observed to have traveled 3.52 cm when the solvent front traveled 8.81 cm. What is the retardation factor (?F)for the compound that composes this spot?

MAKE A METHODOLOGY : MATERIALS/ REAGENTS WITH SCHEMATIC DIAGRAM . THE PICTURE UPLOADED SERVES AS A GUIDE, DO THE SAME THING BASED FROM THE PIC.  Procedure: Place 20 drops of each of 0.2M CuSO4 in a centrifuge tube. Then add 5 drops of freshly prepared 6M (NH4)2S to each centrifuge tube. Record your observation. Centrifuge the mixtures for 3 mins.  and decant the supernatant liquid. Add 10 drops of DI water and 10 drops of 6M HNO3. Stir and boil the mixture in a hot water bath for 5 mins.  centrifuge the mixture for 3 mins. Decant the supernatant solution from procedure 3. Discard the To each of the supernatant liquid, add 6 drops of 6M H2SO4. Allow themixtures to cool and 5 drops of DI water. To the mixtures in procedure 4, add few drops of concentrated NH3 until the solution becomes basic. Confirm using a litmus paper. Record your observation. Add 1 drop of 5M NaOH and 1 drop of 0.1 M SnCl2 to the centrifuge tube containing Bi3+ ion , centrifuge and decant the supernatant liquid. To…

Please answer all 5 questions (it could be short answers). 5-1. What is the main barrier to separating liquid mixtures of less than 500 mL by distillation? 5-2. A sample mixture of ethyl benzoate (bp 212 Celsius) and dodecane (bp 216.2 Celsius) is injected on two GC columns. Column A has DC710 silicone oil as the stationary phase, and column B uses polyethylene glycol as the stationary phase. Which substance would be certain to elute first from column A and would the same material be expected to elute first from column B? Which column, A or B, would be expected to give the better separation of these two substances? 5-3. Question 5-2 refers to separating a mixture of two high boiling liquids by gas chromatography. These materials have similar boiling points. List several GC variables and conditions that would make it easier to separate thesesubstances by gas chromatography 5-4. Capillary GC columns have better resolution than packed columns even though the enormous surface area…

An enzymatic method for determining alcohol in the wine is evaluated by comparison with a gas-chromatography (GC) method. The same sample is analyzed several times by both methods with the following results (% ethanol). The values of alcohol for both enzymatic and GC methods are shown in Table 1. Using a suitable test, determine whether the enzymatic method gives the same value as the GC method at 95% confidence level.

In paper chromatography, which of the following may cause premature separation? Select one: a. Using an open system as the chromatographic chamber b. Using a solvent with high polarity c. Using a solvent with low polarity d. Spotting the concentrate below the solvent level e. Spotting the concentrate on the paper only once

Which of the following chromatographic methods cannot use a mixture of liquid solvents (eluents) during the separation process?     Thin layer chromatography     High pressure liquid chromatography     Column chromatography     Gas chromatography

Preparation of 0.25N NaOH Objective: Apparatus and Materials: Procedure : Calculate the exact mass of NaOH needed to prepare 1.0L of 0.25N NaOH for standardization. Show your computations. Using the triple beam balance, weigh the desired amount of NaOH. Place the weighed amount of NaOH into the 500 mL volumetric flask and add distilled water until it reaches the mark. Agitate and transfer the solution into the reagent bottle. Add again distilled water to the same volumetric flask until it reaches the mark and pour it to the same reagent bottle, thus having a total volume of 1.0 L. Label the reagent bottle, 0.25N NaOH.   Data and Computations:       Conclusion:

Which statement is true? Statement 1: In chromatography, the compound mixture moves along with the mobile phase through the stationary phase and the components get separated depending on the degree of interaction and adhesion Statement 2: Compound A is more soluble in the mobile phase compared to compound B. Thus, compound A would most probably have a higher Rf value.

Tim is interested in analyzing for Pyraclostrobin (pesticide) in strawberries using QuECHers method for extraction and clean up before analysis with HPLC-uv. The concentration of the Pyraclostrobin in the fruits that he sampled is thought to be between 1-10 ng pesticide per g fruit fresh weight. The HPLC-uv instrument he is using has a LoQ of 5 ppb for Pyraclostrobin. Tim is starting out with 500 mg of the sliced fruit

Which of the following could be a consequence of an open and uncovered chromatographic chamber?   I. The travel rate of a component would be faster. II. The chromatographic chamber will not be saturated. III. The mobile phase will take a longer time to reach the end line.   Select one: a. I, II, and III b. I only c. I and III d. II and III

So we lately had a paper chromatography activity and we used a plant with only one pigment (which is red). It was a blot-dry technique using water and ethyl alcohol.    Describe the chromatogram used and the process of indicating the point of origin and the solvent front. Describe how the sample was applied using the "Blot-dry" technique. Describe the solvent system or the solvent used in developing inside the chamber.

Make a schematic diagram for the procedure below: B. % SO3 determination Dry the soluble sulfate sample at 100° C for 1-2 hours, and cool in desiccator. Weigh out 0.5 – 0.7 g (± 0.3 mg) duplicates sample. Transfer to 400-mL beakers. Dissolve each in 200 mL of dist. H2O + 4 mL of 6 m HCl. Precipitant is prepared by dissolving 1.3 g BaCl2 ∙ H2O in 100 mL water. Filter if solution is not perfectly clear. Heat the BaCl2 solution and sulfate sample solution nearly to boiling, and then add the entire amount to the HOT sulfate sample solution while stirring vigorously. Wash stirring rod with distilled water and include washings in your final mixture. Digest by letting stand 1-2 hours. Overnight standing is acceptable. Filter through an ash less filter paper of fine porosity (Whatman no. 42). Slowly pour the supernatant liquid through the filter paper.

Your manager has asked you to develop an analysis method for an ingredient in a perfume product being developed for the cosmetic industry. The ingredient has a high vapor pressure. The lab has instrumental analysis equipment. The manager specifies that in addition to the method being accurate, precise, and specific for the ingredient, it should be inexpensive and generate minimal chemical waste. Select the most promising analysis technique based on the information provided. a) Gas Chromatography (GC) with Flame Ionization Detection b) Liquid-liquid Extraction with Infrared Spectroscopy c) Gel Electrophoresis d) HPLC with Evaporative Light Scattering Detection

Use the following scenario and results to answer the following four questions: Scenario:  It was suspected that a particular drug sample contained three components: X, Y and Z. To check this, the mixture was analyzed by TLC with a nonpolar developing solvent on silica gel. The following TLC plate was obtained. Which components are most likely to be present in the sample?     X and Z     Y only     Y and Z     Y and another unknown component     X and Y

Which of the following statements about the mobile phase in Supercritical fluid chromatography (SFC) is false? A. It requires lower pressures than those needed for HPLC. B. Its mobile phase has the viscosity properties of a gas. C. It has solvent properties of a liquid. D. It has densities similar to a liquid. E. It gives better resolution than GC.

CREATE A SCHEMATIC DIAGRAM USING THE PROCEDURE: Weighing of standard reagents 1. Make an improvised weighing dish for solid samples (i.e. aluminum foil). Put the foil inside the analytical balance. 2. Press TARE. 3. Weigh accurately 0.4000 grams of NaCl powder in the foil. The reading of the weight must not exceed + 0.0030 g. Note that unused or excess chemicals should never be returned to the stock bottle. 4. Close the balance glass door. Note the actual weight of the NaCl powder that is reflecting on the analytical balance. 5. Transfer carefully the contents in a 150-ml beaker.