Solvent used in the elution process would be the mobile phase and solvents of different polarity would have a significant impact on the separation due to the varying solubility of compounds in different solvents. Hexane, being the less polar solvent, interacts mainly with the less polar analytes but very slowly with polar analytes. Therefore using hexane at the start of the elution process allows the less polar compound to be eluted out first. After the complete collection of less polar analyte, the mobile phase was changed to the more polar hexane/ethyl acetate solvent, which has stronger interaction with the more polar component, allowing it to be eluted out faster. The change in solvents throughout the elution process would allow for an effective and efficient separation of the compounds β-carotene and chlorophyll in the crude extract of green leaves. The polar silica gel in the column is the stationary phase and acts as an adsorbent, depending on the affinity of the component towards the stationary phase. In general, the more polar component would have a stronger interaction with the stationary phase, and the less polar component would be eluted out first. From the observations of the column chromatography, yellow S2 collected is β-carotene, indicating that …show more content…
This problem could have arisen from an overly dilute extract used when running the TLC. Prior to conducting TLC, the extracts S2 and S3 were used in the UV-vis spectroscopic analysis. Failing to consider the use of the samples for TLC afterwards, huge proportions of both extracts were disposed off after the spectroscopic analysis. Even though the remaining extract volumes were concentrated by evaporating off the solvent, the number of moles of compounds present were still not concentrated enough for clear visible spots to be obtained from the TLC
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Tn 4351 was originally isolated from bacteroides fragilis  . The transposon was successfully introduced into Cytophaga succinicans, Flavobacterium meningosepticum, Flexibacter canadiansis, Flexibacter strain SFI and Sporocytophaga myxococcoides by conjugation . Tn 4351carries two antibiotic resistance gene. One of the codes for resistance to erythromycin and clindamycin which is expressed in bactroides but not in E.Coli. The other gene codes for resistance in tetracycline and is expressed in aerobically grpwn E. coli, but not in anaerobically grpwn E. coli or in bacteroides.
The goal of this experiment was to isolate three different molecules (acidic, basic, and neutral) from a mixture and identify their molecular structure. This was accomplished by using acid/base liquid extraction and H NMR analysis. The neutral component of the unknown mixture #191 was fluorenone. This was evident due to an H NMR spectra that had a high presence of hydrogen signals in the 7.2- 7.7 ppm range. Chemical shift values for fluorenone stated in the lab manual were 7.27, 7.47, 7.48, and 7.6 (CITE), indicating that the corresponding H NMR spectra for the neutral unknown is of this chemical.
In this lab experiment, I experimented with 2 different amount of borax (1g and 5g) to see if the amount of borax affects the bounce height of the ball. The ball is made up of polyvinyl acetate (school glue), borax and water. In the experiment the independent variable is borax and the dependent variable is the bounce height. I found out that borax has sort of a protective layer that creates the bounciness. Therefore, I hypothesized that the more borax that is used, it would be more bouncy, because there is more of a protective layer to it.
The Identity of the unknown, in this case unknown A, was determined to be acetyl salicylic acid. This was determined by comparing the melting points of the purified unknown crystals to the crude unknown. The known melting point range for acetyl salicylic acid is 135°C -136°C. The Unknown’s melting point was slightly off at 128.6°C - 132°C. This can be due to impurities of the crystals during the purification process.
Conclusion In this lab, the reactivities of different types of hydrogens, including primary, secondary, tertiary aromatic, aliphatic, and benzylic hydrogens, were analyzed. The experiment was conducted twice, simultaneously. One set of test tubes containing bromine, dichloromethane, and one of toluene, ethylbenzene, tert-butylbenzene, cyclohexane, methylcyclohexane, or more dichloromethane (control), were exposed to UV light; the other equal set of test tubes were placed in a fume hood with the light off. This set of test tubes was not fully in the dark.
Abstract: The purpose of this lab was to separate hexane and toluene from a mixture by collecting fractions of both hexane and toluene through simple distillation. Because hexane and toluene have different boiling points they distill at different times and can be separated easily. We found the refractive index by putting our collected fractions in a refractometer. Once we knew the refractive index we could figure out the percentage of both hexane and toluene in the solution. The first fraction was collected from 66°C to 70°C the temperature then dropped and the rose to 98°C and the second fraction was collected from 98°C - 100°C.
Although the separation and the identity of the products were definite on the TLC plate; to improve the results, the solvent system could have been changed to 7:3 or 5:5 Hexane: Ethyl Acetate. Adding more Ethyl Acetate to the system should have provided more separation and the spots should have moved up the plate
Unknown Lab Report Mikee Lianne Gonzales Biol 351- 1005 Holly Martin Unknown: # 76 Abstract This report is about identifying the respective genus of the given unknown organism. The goal is to show and prove the student’s understanding of microbiology and laboratory learned experimental techniques.
Liquid chromatography is first being discovered by a Russian botanist, Mikhail Tsvet. Tsvet had rose the idea of liquid chromatography when he tried to purify and separate the coloured plant pigments by using a liquid-adsorption column containing calcium carbonate in 1890s. He also applied his observations with filter paper extraction to the new techniques for analysis the components in the petroleum. The filter paper extraction is the precursor of paper chromatography. He also found that the polarities of the solvents were important when during the separation to ensure that the solutes which were non-polar and polar can be separated efficiently.
The purpose of this experiment was to learn about metal hydride reduction reactions. Therefore, the sodium borohydride reduction of the ketone, 9-fluorenone was performed to yield the secondary alcohol, 9-fluorenol. Reduction of an organic molecule usually corresponds to decreasing its oxygen content or increasing its hydrogen content. In order to achieve such a chemical change, sodium borohydride (NaBH4) is used as a reducing agent. There are other metal hydrides used in the reduction of carbonyl groups such as lithium aluminum hydride (LiAlH4).
Unknown Lab Report Unknown # 25 By: Jenna Riordan March 19, 2018 Bio 2843 1. Introduction Microbiology is the study of microorganisms found in all different environments throughout Earth, from the hot thermal vents at the bottom of the ocean to the ice at the top of a mountain.
TLC was used to identify the actual unknown product as well as other products/reactants present in the filtered solution. The procedure was conducted by placing a TLC plate in a developing chamber that is filled with a small amount of solvent. The solvent cannot be too polar because it will cause spotted compounds on the TLC plate to rise up too fast, while a very non-polar solvent will not allow the spots to move. The polarity of the spots also determines how far it moves on the plate; non-polar spots are higher than polar ones. After spots on the TLC form, the Rf values are calculated and used to analyze the similarity of the compounds.
Properties of Substances Express Lab 1)The purpose of this lab was to compare the physical properties of different types of solids and how the properties of solids are determined by their intermolecular forces and their intramolecular bonds. Then we were to classify each type of solid as either ionic, metallic, non-polar molecular, polar molecular, or network. Paraffin wax classified as a non-polar molecular, Silicon dioxide was classifies as a network, Sodium chloride was classified as ionic, Sucrose was classified as polar molecular and Tin was classified as metallic. (2)The intermolecular forces that are present in Paraffin wax are dispersion forces, because it is non-polar and carries a negative charge. Followed by Sucrose that has
DETERMINATION OF PERCENTAGE ETHANOL IN BEVERAGES 1. Introduction to Gas Chromatography Gas chromatography is a very powerful separation technique for compounds that are reasonably volatile. The components of a sample partitions into two phases, the 1st of these phases is a immobile bed with a great surface area, and the other is a gas phase that permeates through the immobile bed. The sample is evaporated and passed by the mobile gas phase or the carrier gas through the column. Samples separates into the stationary liquid phase, based on their solubilities at the given temperature.