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Chromatography of River Water
Please help with the following problem. Suppose that you must go into court and testify as to the level of X in the river water. Your lawyer is concerned that your analytical results are lower than they should be because you cannot extract with benzene (distribution Ratio K=4) all of X from your samples. Assume the concentra
Reversed-phase liquid chromatography Questions
A mixture of organic acids was separated by reversed-phase liquid chromatography. The data obtained for the chart recording were as follows: For acid A, the peak appeared 22 cm after injection with a full width at baseline of 8 cm. For acid B, the peak appeared 34 cm after injection with a full width at baseline of 6 cm. A non-r
The Interpretation of Gas Chromatograms
A chromatogram would feature lines instead of peaks if: a) the best equipment available is used b) the separation is done by capillary electrophoresis c) if the temperature nears (or is equal to) the absolute zero d) neither of the above cases would suffice. B. Most modern chromatography instruments are equipped with: a)
Thin Layer Chromatography Techniques
In thin layer chromatography what is the Rf's mean? How are they used? What factors affect the Rf of a compound?
if can not detect a chemical by UV-VIS detector, what other methods(detector) for getting higher sensitivity can be used?
Surface Acidity and Fluorine-Doping
In the attached paper, the authors claim that F-doping enhanced surface acidity. Why does the presence of fluorine increase surface acidity? Reference: Li, D., Haneda, H., Hishita, S., Ohashi, N., & Labhsetwar, N. K. (2005). Fluorine-doped TiO< sub> 2</sub> powders prepared by spray pyrolysis and their improved photocatalyt
Choose any type of chemical analyte in a food product and please describe in detail how to analyze the analyte using a reverse-phase HPLC. Please include sample preparation, extraction and indicate what mobile phase, column, and detector were used.
GC peak area problem
I have the areas under the peak for unknown and standard + unknown in Gas chromatography. How do you calculate the % analyte? The unknown areas Peak 1 Retention time Peak area %AREA 0.980 16.92 3.79% peak2 3.175 429.71
Please write the expected results (e.g., sensitivity, variance, linearity, application) regarding the extract and analysis of isoflavone from your references and then please write detailed efficiency choose HPLC-PAD efficiency to analysis of isoflavones (sensitivity, variance etc) from snack bar like discussion part.
Please help with the following problem: Refer to the GLC traces given in Figure 6.16. These are analyses of the various fractions collected during the fractional distillation of the mixture of cyclohexane and toluene. The weight and mole correction factors (flame ionization detector) for cyclohexane are 0.84 and 0.78, respec
Solubility of Organic Compounds Lab Report
Lab 3: Solubility of Organic Compounds Objectives: - Understanding the relative solubility of organic compounds in various solvents. - Exploration of the effect of polar groups on a nonpolar hydrocarbon skeleton. Introduction: The solubility of a solute (a dissolved substance) in a solvent (the dissolving medium) is
Organic chemistry pre-lab questions
1. Why is it dangerous to heat a liquid in a distilling apparatus that is closed tightly at every joint and has no vent to the atmosphere? 2. In your distillation of the binary mixture, which fractions contained more of the higher boiling component, the earlier fractions or the later fractions? expriment procedure
Size Exclusion Chromatography and SDS-PAGE
Describe whether, and how, size exclusion chromatography and SDS-PAGE can be used to determine the molecular weight and oligomeric status of a protein. Indicate whether it is necessary to compare the protein's mobility relative to standards of known molecular weight.
Consider immobilized metal affinity chromatography, such as a Ni2+ column. For this type of chromatography, describe the basis of separation of the protein components. Why do the proteins of interest bind to the resin and how are solvent conditions changed to promote elution?
Gel-Filtration / Size Exclusion Chromatography
Why do smaller molecules elute after large molecules when a mixture of proteins is passed through a size-exclusion (gel filtration) column?
Myoglobin and Hemoglobin HPLC
I conducted HPLC analysis of myoglobin and hemoglobin using a C18 and C4 column. Both proteins were in a buffer solution only. On the C4 column the order of the peaks was a reverse of the C18 column. The chromatographic output showed two peaks. Looking at the UV absorbance, I can attribute one of the peaks to the heme group (
Protein Purification Questions
Hey I am did a multiweek experiment doing a protein purification of Glutamate-Oxaloacetate Transaminase (GOT). I have a few questions about my experiment. 1. How does protein purification help in the real world? What's the larger picture? 2. I preformed a GOT Assay, GDH(Glutamate Dehydrogenase) Assay, Folin-Ciocalteau Ass
High-performance liquid chromatography
I recently did an experiment on high-performance liquid chromatography I am having a little trouble in the introduction. The introduction should just be a description of High-performance liquid chromatography and what I will learn from the experiment. I wrote a draft but my TA said that it could use some work. I was wondering if
Questions about HPLC Lab
Hey I am about to do a lab to determine the amount of caffeine and sodium benzoate in soft drinks via HPLC. To prepare I had to answer a series of questions before the lab. I am confused on some of them and request your help. The questions are: Why is it necessary to perform the HPLC separation at a pH of 3? How does the pH a
Quantitative Analysis : HPLC Chromatographs and Beer's Law
Please see the attached file for the fully formatted problems. 1.Based on the following figure explain which particle size produce the best resolution in HPLC and why? 2. To find the Ce4+ content in a solid, 4.37 g were dissolved and treated with and excess of iodate to precipitate Ce(IO3)4. The precipitate was filtered, w
Combined Gas Law and Mixtures of Gases
Introduction to the Ideal Gas Law A balloon is floating around outside your window. The temperature outside is 31 , and the air pressure is 0.700 . Your neighbor, who released the balloon, tells you that he filled it with 3.60 of gas. What is the volume of gas inside this balloon? Express your answer numerically in liters.
NMR Spectrum of Caffeine and Vapor Pressure of Sublimation
A. How many peaks would you expect to fin in the NMR spectrum of caffeine? B. What characteristic absorptions of bands would you expect to find in the infrared spectrum of caffeine?And show the infrared spectrum C. the vapor pressure of 1,2-dipheneylethane, p-dichlorobenzene, and 1,3,5-trichlorobenzene are 0.06, 11.2,
Gas Chromatography Questions
1. in gc (gas chromatography), what is the stationary phase? what is the moving phase? 2. as with the other chromatographic techniques we've studied, the polarity of the compounds affects their separation in gc. what is the other dominant factor that affects separation? 3. what would be the effect of increasing column temperat
Column Chromatography Layers
-Why is a layer of sand above the alumina in the column in column chromatography? - What are the differences between column chromatography and thin layer chromatography? - If a compound had an Rf value of .5 in a particular solvent, how many column lengths of that solvent would it theoretically require for the compound to
Why Didn't my Chromatography Experiment Work Properly?
I did a lab on column chromatography and thin layer chromatography, and our sample was a spinach extract. I am trying to figure out if there is a correlation between the partition coefficient and the Rf used in thin layer chromatography. Is there one? For the column chromatography we used a 9:1 hexane: acetone, thenn 1:1 h
Oxidation or Reductive Process
Is the radical chlorination of methylcyclopentane an oxidation or reductive process?
Silica Gels Formation
Explain the chemistry behind silica gel formation.
VOC Machine Printout
Help my understand and interrupt the VOC machine print out on three water samples.
Conversion of formalin to a solution of methanol
I am a pathologist and would like to know just how hard it would be to convert the used formalin (10% formaldehyde in water) to a solution of methanol. It seems to me that I just need a long column and bubble hydrogen gas through it. When the hydrogen gas is able to make it all the way to the top of the column all the formalin
Rf value on structural basis
1. The relative movement of the substance is related to polarity of the substance. The TLC sheet is coated with highly polar silica gel and the solvent has a much lower polarity. Explain the relative Rf values on a structural basis. 2. Explain why leaves " change color" in the fall. 3. How does the Structure of chlorophyll