...Thin-Layer Chromatography PRELAB READING/VIDEO: See video on Blackboard Zubrick: Cleaning, Chapter 9 pp. 77-79; Chromatography, Chapter 26 pp. 218-221 TLC Chapter 27 pp. 222-235, Melting Point Chapter 12 pp.88-93 PURPOSE: The purposes of this experiment are to: (1) determine the optimal conditions for separating substances in a mixture using thin-layer chromatography (TLC), and (2) use thin-layer chromatography and infrared spectroscopy to identify an unknown solid. EXPERIMENTAL TECHNIQUES: thin layer chromatography, infrared spectroscopy. This is a 2 week experiment. INTRODUCTION Thin-layer chromatography (TLC) is a quick, inexpensive procedure that provides the chemist information on the purity of a sample, while using a minimal amount of that sample. Chemists often use TLC after running a chemical reaction to determine the purity of their product. In this lab, you’ll be (1) determining the best solvent to use for a TLC separation of four known compounds (shown below), (2) studying how experimental parameters (the type of development chamber, the presence of a filter paper “wick,” and how well the development chamber is sealed ) affect the results of a TLC experiment, (3) determining the reproducibility of Rf values, and (4) identifying an unknown compound using TLC. Before the lab, be sure to read the chapter(s) in Zubrick on thin layer chromatography! The four compounds you’ll be studying are shown below. CHM25701 Spring 2015 Thin Layer...
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...BAB I PENDAHULUAN 1.1 LATAR BELAKANG Perkembangan ilmu pengetahuan pada zaman sekarang telah berkembang dengan cukup pesat, terutama di bidang teknologi itu sendiri. Termasuk dalam bidang kedokteran itu sendiri. Pada makalah ini akan dibahas mengenai salah satu teknik ataupun metode yang digunakan dalam bidang kedokteran yaitu kromatografi terutama kromatografi lapis tipis. Kromatografi adalah teknik kromatografi adalah teknik pemisahan suatu zat yang didasarkan pada perbadaan kecepatan migrasi komponen-komponen yang dipisahkan diantara dua fase, yaitu fase gerak dan fase diam. Istilah kromatografi pertama kali ditemukan oleh Michael Tswatt (1903), seorang ahli botani asal Rusia. Kromatografi sendiri berasal dari bahasa Yunani yang terdiri dari dua kata yaitu, “chromos” yang berarti warna dan “graphos” yang berarti menulis. Jadi kromatografi berarti penulisan dengan warna. Kromatografi sendiri dapat diklasifikasikan lagi menjadi empat teknik yaitu adalah Kromatografi Kertas (KKT), Kromatografi Lapis Tipis (KLT), Kromatografi Gas Cair (KGC), dan Kromatografi Cair Kinerja Tinggi (KCKT). Pada makalah ini akan dibahas mengenai kromatografi lapis tipis (KLT). Kromatografi lapis tipis adalah salah satu teknik kromatografi yang banyak digunakan karena penggunaanya yang mudah dan cukup murah. Metode ini menggunakan lempeng kaca atau lembaran plastik yang ditutupi penyerap untuk lapisan tipis dan kering bentuk silika gel, alomina, selulosa dan polianida. Untuk menotolkan...
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...Abstract Chromatography is a method of separating and analyzing different mixtures of chemicals. You make separation of closely related compounds happen by allowing a mixture to seep through different absorbents such as paper or gel so that each compound is absorbed into a separate often colored layer. Introduction The objective of this preparative experiment is for students to become familiar with a technique known as Chromatography. This technique is used to take mixtures and separate small quantities of them into their component parts. There are many types of chromatographic techniques, but the ones that were used in this experiment were paper chromatography and thin layer chromatography. Paper chromatography was used to analyze food colors, where as thin layer chromatography was used to analyze amino acids. Both of these techniques have two phases, known as the stationary phase and moving phase. The stationary phase is the material used, through which the mobile phase flows. The mobile phase is usually known as the developing phase, and is a solvent or a mixture. The compounds that were synthesized for paper chromatography were 1-propanol and 1-butanol. The compounds that were synthesized for thin layer chromatography were dimethoxyethane and absolute ethanol. In the first experiment, paper chromatography was used to show the separation of food color components. This was done by using different food colorings and determining what colors were mixed in order to get red...
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...from spinach leaves (including chlorophyll a, chlorophyll b and beta carotene). The experiment also compared and contrasted two different methods of separation. The first part of the experiment explored column chromatography and the second part explored thin-layer chromatography. Introduction: (3 marks)* The three pigments that can be extracted from spinach (chlorophyll a, chlorophyll b and beta carotene) all differ based on their polarity, which arises from functional groups in their structure. The most effective way to separate pigments from spinach is based on their differences in their polarities and this lab explored two chromatographic methods to do so. Chromatography is the technique of separating organic mixtures by allowing them...
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...EXPERIMENT 6: THIN LAYER CHROMATOGRAPHY. THE OBJECTIVE OF THE EXPERIMENT. 1. To separate the unknown amino acids mixture into its various components. 2. To identify the amino acids present in the unknown amino acid mixture. THE THEORY BEHIND THE EXPERIMENT. Chromatography is a method of separating a mixture into its components, by use of heterogeneous equilibrium established during the flow of the solvent called a mobile phase through a fixed (stationary) phase. The stationary phase can be either solid or liquid, while the mobile phase can either be a liquid or a gas. Therefore, chromatography can be classified as; solid- liquid, liquid- liquid, or gas- liquid. Experimentally, chromatography can be carried out in columns or in layers. The column chromatography uses a vertical tube packed with a medium/ adsorbent. The layer chromatography uses a thin layer embedded unto a plate unto which the samples are introduced. The thin film stationary phase may be: 1. A liquid (partition chromatography). Example is paper chromatography. 2. A finely divided adsorbent solid. (Adsorption chromatography). Example is Thin Layer Chromatography. INTRODUCTION TO THE EXPERIMENT. Thin layer chromatography (TLC) is a chromatography technique used to separate mixtures.[1] Thin layer chromatography is performed on a sheet of glass, plastic, or aluminum foil, which is coated with a thin layer of adsorbent material, usually silica gel, aluminium oxide, or cellulose (blotter paper). This layer of adsorbent...
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...Erin Mollberg September 14, 2015 TLC Analysis of Analgesic Drugs Introduction The purpose of this experiment was to determine the content of various over-the-counter analgesics using thin-layer chromatography. Experiment Scheme Equation 1: Near the bottom of a TLC plate, a small amount of a known analgesic was spotted about 1.0 cm away from the bottom of the plate along with a reference spot for the control. This was repeated on another plate using unknown analgesics. The plates were then placed in a jar of solvent to develop, where only the bottom of the plates were submerged. Once the solvent reached about 0.5 cm from the top, the plates were removed from the jar and the solvent front was marked on each. The plates were then observed with a UV light where spots were observed and sketched onto the plates. The retention factor (Rf) was then determined by measuring (in millimeters) the distance each spot had traveled relative to the solvent front. An iodine analysis was also done by placing the plates in a jar of iodine crystals until spots began to appear. The visibility and relative color of each spot was observed. Data Name | Formula | MW(g/mol) | Hazards | acetaminophen | C8H9NO2 | 151.17 | Irritant, harmful if excess swallowed. | aspirin | C9H8O4 | 180.16 | Irritant, harmful if excess swallowed. | caffeine | C8H10N4O2 | 194.09 | Irritant, harmful if excess swallowed. | salicylamide | C7H7NO2 | 137.14 | Irritant, harmful if excess swallowed...
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...Separating and Determining the Colored Components of Capsicum fructescens Using Column and Thin Layer Chromatography Duran, K., Ednalino, M., Encarnacion, F., Fernandez, T., Fernando, S., Garcia, D. 2D-Pharmacy, Group 4, Department of Pharmacy, Faculty of Pharmacy, University of Santo Tomas, España Boulevard, 1015 Manila, Philippines ABSTRACT Chromatography was used to separate and determine the purity of the colored components present in a substance. Separation of the colored components of Capsicum fructescens (Red Siling Labuyo) using column chromatography, determining the purity of the components using thin layer chromatography (TLC), and measuring the retention factor (Rf) values of the colored components in TLC were the aims of the experiment. Dichloromethane:Hexane (DCM:Hexane) (1:1) was used to extract the pigments of the red siling labuyo. For the column chromatography, 0.5 mL of the extract was placed on top of the column containing silica gel. DCM-Hexane, DCM, and DCMmethanol was introduced in succession. Colored eluates were collected on separate test tubes and noted the number of drops for each. For the thin layer chromatography, the eluates were spotted on a pre-coated TLC plate and was placed on an equilibrated chamber, with DCM:Hexane as the solvent system. After visualizing the results on the TLC plate, the distance traveled by the pigments were computed for the Rf values. The results showed that the yellow pigment had the greatest distance traveled...
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...THIN LAYER CHROMATOGRAPHY (TLC) Thin Layer Chromatography is a simple, fast, multipurpose, sensitive, inexpensive analytical technique for the separation of substances. TLC has a mobile phase that is a liquid while the stationary phase is an active solid, known as the sorbent. Such sorbents are silica, cellulose, alumina, polyamides, ion-exchangers, and other numerous minor organic and inorganic sorbents. The considerable versatility of the sorbents depends on the type of substances being separated. TLC has been successfully applied to hydrophilic, lipophilic and inorganic separations. HIGH PERFORMANCE THIN LAYER CHROMATOGRAPHY (HPTLC) High Performance TLC can also be taken to be the conventional TLC with increased efficiency without decreasing the resolution and selectivity. To increase the efficiency of Thin Layer Chromatography, a couple of issues must be looked into. Efficiency is the kinetic variable determined primarily by the physical characteristics of the chromatographic systems, such as the size and uniformity of the adsorbent particles and the flow rate of the mobile phase. The efficiency of the system is slightly dependent on the nature of the solute. Efficiency is calculated as the theoretical plate number: N=(X/W) 2 Where, X is the distance species moved from the origin W is the zone width. N is the theoretical plate number. * High efficiency...
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...agent. It was synthesized to alter the corrosive nature of Salicylic acid that causes gastric pain in the mouth and esophagus. Aspirin can be synthesized by the reaction of Salicylic acid with acetic anhydride and 85% Phosphoric acid as the catalyst when heated in a water bath at 90°C. The formation of white crystals after scratching the solution and after cooling in an ice bath indicates the presence of the product formed after the reaction. Solubility test with water and toluene, melting point determination by oil bath and thin layer chromatography by different kinds of solvents such as 10%EA in DCM, 30%EA in DCM, 10% hexane in EA and 10% DCM in Acetone are confirmatory tests for the presence of Acetylsalicylic acid. Thin layer chromatography is an analytical technique to determine the identity of the substances and to determine the effectiveness of purification. Keywords: Acetylsalicylic acid, solubility test, melting point, thin layer chromatography Introduction Acetylsalicylic acid, commonly called “aspirin” is an analgesic, an antipyretic and an anti-inflammatory agent. Aspirin was synthesized by Charles Gerdhadt but was patented to the Bayer Company by Felix Hoffman. It was synthesized to alter the corrosive nature of salicylic acid that causes gastric pain in the mouth and esophagus attacking the mucous membrane, which was intended to cure not to worsen the pain. It contains not less than 99.5 percent of 2-(acetyloxy)benzoic acid. Aspirin is a...
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...detecting alkaloids, in particular nicotine, from Nicotiana rustica tobacco seedlings up to 2 mm in length has been developed. Growing tissue is applied (squashed) directly onto silica gel plates for thin-layer chromotographic analysis. The sensitivity of this method permits the detection of quantities of nicotine as small as 0.4 microgram. INTRODUCTION During the course of our study on the chemical patterns of plant growth and development (Peters et al., 1972), it was necessary to use rapid procedures to analyze chemical contents of growing tissues. The present study deals with the development of a procedure for the rapid detection of the alkaloids. The histochemical detection of alkaloids in growing tissues, as demonstrated by others (Chaze, 1932; James, 1950), is based on the reaction with iodine in potassium iodide solution. These methods are complicated by the presence of carbohydrates and proteins, which also react positively to iodine in potassium iodide solution. James (1946) was able to overcome the difficulty of liberating alkaloids from denatured proteins by blotting the tissue on filter paper prior to other treatment; however, the blotting procedure results in partial loss of cellular alkaloid content. A tedious solvent extraction procedure followed by thin-layer chromatography has been used by Speake et al. (1964). Other workers have used the reliable but time-consuming steam-distillation extraction technique (Solt, 1957; Brown and Byerrum, 1952). This paper describes...
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...Chromatography Aim: To test the purity of aspirin using chromatography. Vocational context The results which we have collected while doing this chromatography will be helpful to many different types of people. One group of people who will be interested in the results is doctors when a patient comes to visit the doctor with a virus or something the doctor can look at these results and they will be able to make a decision on how powerful the aspirin to give the patient. Another group of people who might take an interest to these results are drug testers Background science Aspirin also known as acetylsalicylic acid, is a salicylate drug, often used as an analgesic to relieve minor aches and pains, as an antipyretic to reduce fever, and as an anti-inflammatory medication. Aspirin separates and decomposes very quickly in hydroxide and alkali metals. Aspirin is stable in dry air but gradually hydrolyses when it comes into contact with moisture Chromatography can be used to separate mixtures of coloured compounds. Mixtures that are suitable for separation by chromatography include inks, dyes and colouring agents in food. There is two phases the mobile phase which flows through column, carries analyte and the stationary phase which stays in a place, does not move. The separation of the molecules is based on the partitioning between the mobile and stationary phase. Chromatography is used in labs often to separate different compounds A TLC plate is a sheet of glass...
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...biomolecules that are used primarily for structural components of the cell, signaling molecules and energy storage purposes. Lipids are naturally occurring esters of long chain fatty acids with both hydrophobic chains, which is insoluble to polar organic solvents and hydrophilic chains which is soluble to polar organic solvents. Because of this conformation, they can assume a wide range of complex structures including fused rings. Lipids can be isolated from cells through different techniques and their presence can be tested through different qualitative tests. The sample choice is egg yolk and was used as a source of lipids in the experiment. Liquid-liquid extraction, separation of the organic and aqueous layer was used to extract the supernatant or extract. Also, thin layer chromatography or TLC was used to separate the different lipid components by using the Rf values computed. The farther the distance traveled by the compound (higher Rf), the more nonpolar the component, while the smaller the distance traveled, the more polar the component (lower Rf). Lecithin and cholesterol was not able to travel the plate. After, the isolated lipid was subjected to qualitative tests such as Acrolein test, test for phosphates, Leibermann-Burchard test and test for unsaturation. Acrolein tests determine the presence of glycerin; the test for phosphate detects phosphate groups in the structure of the lipid, Leibermann-Burchard uses cholesterol as the standard and detects the presence of steroids and...
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...Name: Srikant Tulsi Reg # 10/0705/0497 Experiment # 4 Date: 5/11/2014 Partners: Shefali Seecharran Pride Ade-Thomas Claude Fraser Title: Synthesis of 9,10-Dihydroanthracene-9,10-Endo-α,β – Succinic Anhydride Reactions: Reaction Mechanism Physical Properties Table: Chemical | Formula | M.W (g/mol) | Quantity (g or ml) | Amount( moles) | Molar Equivalent | M.P(OC) | B.P (OC) | Density\(g/cm3) | Yield (g) | % yield | Anthracene | C14H10 | 178.23 | 2.018 g | 0.0113 | 1 | 215 | 339 | 1.28 | | | Xylene | C8H10 | 106.16 | 2.5 ml | 0.0022 | 1 | -47.4 | 138.5 | 0.864 | | | Maleic Anhydride | C4H2 O3 | 98.06 | 1.001 g | 0.0102 | 1 | 52.8 | 202 | 1.480 | | | Hexane | C6H14 | 86.18 | - | - | | -96 | 68 | 0.655 | | | DCM | C10Cl2 | 84.93 | - | - | | -96.7 | 39.6 | 1.327 | | | Ethyl Acetate | C4H8O2 | 88.11 | - | - | | -83.6 | 77 | 0.897 | | | 9,10-Dihydroanthracene-9,10-Endo-α,β – Succinic Anhydride | C18H12O3 | 276.29 | - | - | | 262-264 | | | 2.326 | 82.43 | Calculations: * Calculating the number of moles of Anthracene Mass of Anthracene Used is 2.018 g Molar Mass is 178.23 g/mol Number of moles = MassMolar mass = 2.018 g 178.23gmol = 0.0113 moles * Calculating the number...
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...3. INTRODUCTION Organic compounds are isolated either from natural sources or from reactions mixtures. These compounds are seldom pure and are usually contaminated with small amounts of other similar compounds, which are found to exist together or formed during the reaction. In order to characterize them, it is important to purify them. 4. PROCESSES FOR PURIFICATION 1. Crystallization 2. Sublimation 3. Distillation 4. Chromatography 5. Differential Extraction 6. Qualitative Analysis 5. 1. CRYSTALLIZATION Aim To separate a solid compound in pure and geometrical form. Principle A saturated solution of the impure substance in a suitable solvent is made at a temperature higher than the room temperature. On cooling this solution, the substance reappears in the form of well shaped crystals. Process Purification by crystallization involves the following steps: Choice of solvent Preparation of solution Filtration of the solution Separating the crystals Drying of crystals Example Crystallisation of Phthalic acid 6. 2. SUBLIMATION Aim To separate volatile solids, which pass directly into vapour state on heating from a non-volatile solid. Principle A mixture of solid substances, such as camphor, benzoic acid, ammonium chloride, iodine etc., containing non-volatile substances, when heated, change directly into vapour without passing through the liquid state. Process 7. Fig :-Sublimation 8. 3. DISTILLATION Aim To separate a solution of a solid in a liquid and for separating a solution...
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...Purity of a substance report Create a report describing the factors that influence the purity of a substance. It is important that chemical substances are as pure as possible. This reduces the chances of unnecessary side-effects and helps ensure an accurate dose in each tablet/substance. The purity of a substance or compound can be established by using data from its melting point or boiling point and from thin layer chromatography. Impure compounds have a range of melting and boiling points, as different substances contain different things they will have different boiling and melting temperatures. Sometimes the different substances may interfere with each other’s melting and boiling points. However the pure compounds have definite boiling and melting points. The presence of an impurity usually lowers the melting point and raises the boiling point. The greater the amount of an impurity, the bigger the differences from the true melting point and boiling point. Thin layer chromatography is similar to paper chromatography, but instead of paper, a thin layer of power is coated onto the plastic plate or glass. Different types of powders and solvents are used; this depends on the type of substance being separated. The results of a pure substance should show that the substance produces just one spot on the plate and the distance travelled by the substance is identical to known sample of that substance on the same plate. Weighing, mixing, heating, cooling, filtration, washing and...
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