B. There was big news all over the internet that the Ponkan oranges that were imported from one of our neighboring counties are heavily contaminated with pesticides. Your lab was asked to analyze these samples using a gas chromatographic procedure. 7. Some samples do not show any signal for the pesticides, your boss told you to use a Solid-Phase Microextraction (SPME) for the extraction procedure. Explain how SPME works and what are the advantages of using this over the liquid-liquid extraction method.

B. There was big news all over the internet that the Ponkan oranges that were imported from one of our neighboring counties are heavily contaminated with pesticides. Your lab was asked to analyze these samples using a gas chromatographic procedure. 7. Some samples do not show any signal for the pesticides, your boss told you to use a Solid-Phase Microextraction (SPME) for the extraction procedure. Explain how SPME works and what are the advantages of using this over the liquid-liquid extraction method.

EBK A SMALL SCALE APPROACH TO ORGANIC L

4th Edition

ISBN:9781305446021

Author:Lampman

Publisher:Lampman

Chapter89: Thin-layer Chromatography

Section: Chapter Questions

Problem 1P

See similar textbooks

Similar questions

Give the advantages and disadvantages of sequential injection analyzers compared to traditional flow Injection analyzers.
PART1: Put True (T) or False (F) for the following sentences: 1. chromatography" derived from two Greek words "Chroma" meaning color and "graphein" meaning to write. The stationary phase may be a solid, or a liquid supported on a solid or gel. 3. The mobile phase may be 2. Solid. 4. Silica gel is the most common stationary phase in adsorption chromatography. 5. Liquid Chromatography abbreviated as (GC ). 6. In Thin Layer Chromatography, the mobile phase is gas. 7. a = KB/KA, where Kg is the distribution constant. 8. k'B and k'A are the retention factors. 9. Rf, is the distance traveled by the compound ONLY. 10. Chromatography is a physical method of separation.
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
what is chromatography? Explain different types of chromatography and explain how to seperate compounds. indicate stationary phase mobile phase.
You are given a container with Na3PO3 that is reportedly contaminated. You are asked by your supervisor to determine the percent purity of that sample in order to know the next measures to be taken by the plant. The following are the procedures that you need to do: a. Dissolve sample weighing 1 g in 35 mL water. b. Prepare solution with 45 mL 3% w/v HgCl2, 30 mL 10% w/v C2H3NaO2 and 10 mL CH3COOH. c. Digest sample then filter then rinse the precipitate that weighs 0.2857 g. d. Compute for the % purity.
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.
a) What would you see if you ran a Thin Layer Chromatography (TLC) on a mixture of the three solids shown below using silica gel as the stationary phase and ethyl acetate/hexanes as the mobile phase? Whichsolid would have the highest Rf and which would have the lowest Rf? Explain b) Would changing the mobile phase (from part a) and increasing thepolarity by introducing small amount of methanol to the mobile phase change the order ofRf of the above 3 compounds? Explain c) Another type of chromatography is Reverse Phase Chromatography. In this type ofchromatography, the stationary phase is non-polar and the mobile phase is polar. If astudent performed Reverse Phase TLC on the mixture of 3 solids (from part a),what would be the order of Rf’s of the compounds? Which would have the lowest Rf andwhich would have the highest Rf?
B. There was big news all over the internet that the Ponkan oranges that were imported from one of our neighboring counties are heavily contaminated with pesticides. Your lab was asked to analyze these samples using a gas chromatographic procedure. 9. Substances Chlorobenzilate and BFB have retention times of 17.1 and 17.60 min, respectively, on a 300-cm column. An unretained species pass through the column in 1.30 min. The peak widths (at base) for Chlorobenzilate and BFB are 0.11 and 0.21 min, respectively. Calculate (a) Capacity Factor for compound both compounds, (b) Selectivity Factor (c) Resolution of the column and d) Average Number of Theoretical Plates
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.
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.
The surface of the silica gel has a structure that looks like this diagram below. Suppose you used a plate coated with silica gel, with propanone, CH3COCH3, as the solvent for thin-layer chromatography. Suppose also that the mixture you were trying to identify contained benzaldehyde benzanilide phenol 1) rank the Rf value from large to small 2) name the IMF between each compound and the silica gel OH OH OH -0-Si-O-Si-O-Si-O- O main body of silica structure
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?