Name :SiphesihleGamede
Student number : 213571124
Experiment : #10
Date : 4 March 2015
Experiment Name : High Performance Liquid Chromatography (HPLC), Quantification of caffeine in various drinks
Aim
The aim of this experiment was to ascertain the concentration levels of caffeine in cola soft drink samples such as coke, monster and red bull by utilising the internal standard method using HPLC. The experiment was also aimed at investigating the use of solid phase extraction for sample clean-up.
Figure 1.1 shows a skematic diagram of an HPLC system. Figure 1.2 shows a skematic diagram of a solid phase extraction system.
Introductory Questions
Define SPE and explain the role of each of the steps used to prepare the SPE cartridge for the isolation of the analyte.
Solid phase extraction (SPE) is an extraction method that uses a liquid and solid phase to isolate a single analyte or a specific type of analyte from a solution. It is usually used to clean up a sample before using a chromatographic or other analytical method to quantify the amount of analyte(s) in the sample.
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One of the reasons why SPE is a suitable technique for this analysis is the fact that there should be higher recoveries (% recoveries)since both caffeine and theophylline are polar compounds, with theophylline being more polar than caffeine which tells us that caffeine will have the longer retention time than theophylline. Other reasons include advantages such as SPE provides cleaner extracts and is easier to automate compared to other extraction …show more content…
There is a mathematical treatment called the ‘Fourier transformation’ and it is used to produce a spectrum and to interpret the data, hence the name FTIR spectroscopy. In general, infrared spectroscopy measures the ability of certain molecules to absorb infrared radiation. The radiation beam passes through a sample and then through a detector where the signal being produced is a function of optical path difference called an interferogram. The design of the FTIR is in such a way as to allow the use of capillary columns which produce sharper
This addition aids in controlling the reproducibility and retention. Separation of the mixture via RP-HPLC can be done using continuous gradient or stepwise to move out the sample components. For every separation, the ideal gradient and volume must be
Fourier transform infrared (FTIR) spectroscopy was obtained. FTIR spectroscopy represents transmittance of light, reflection, absorption, and emission indicated in gases, liquids, and solids. At specific wavelengths, infrared (IR) light—an interaction between light and matter— can distinguish types of energized bonds that absorb IR light. However, the bond and electromagnetic radiation frequency must match.
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.
The lab started off by measuring critical materials for the lab: the mass of an an empty 100 mL beaker, mass of beaker and copper chloride together(52.30 g), and the mass of three iron nails(2.73 g). The goal of this experiment is to determine the number of moles of copper and iron that would be produced in the reaction of iron and copper(II) chloride, the ratio of moles of iron to moles of copper, and the percent yield of copper produced. 2.00 grams of copper(II) chloride was added in the beaker to mix with 15 mL of distilled water. Then, three dry nails are placed in the copper(II) chloride solution for approximately 25 minutes. The three nails have to be scraped clean by sandpaper to make the surface of the nail shiny; if the nails are not clean, then some unknown substances might accidentally mix into the reaction and cause variations of the result.
Elijah Brycth B. Jarlos IX-Argon 1. Multicellularity is a condition of an organism to have multicellular cells. An example of a organism who has multicellular cells are plants, animals, and humans. The main reason of why scientists have a hard time finding a good set of existing organisms to compare. Is neither the first set of organisms which is being compared is dying as fast as the second specimen is being examined or they just can’t find the right species.
The objective of the sludge lab was to determine how many different pure substances were in the sludge by using the methods and techniques we have learned throughout the year. We had to pick separation methods so we could separate our sludge and then test characteristic properties on our separated liquids and solids. This experiment made us use our knowledge on characteristic properties to pick the ones we should test to help us identify our pure substances. Characteristic properties are properties that help identify a solid or liquid. Each solid or liquid has a certain density, boiling point, solubility, flammability, so if you know what each one is then you can use that information to help you identify your solid or liquid.
INTRODUCTION A gas chromatograph (GC) can be utilized to analyze the contents of a sample quantitatively or in certain circumstances also qualitatively. In the case of preparative chromatography, a pure compound can be extracted from a mixture. The principle of gas chromatography can be explained as following: A micro syringe is used to inject a known volume of vaporous or liquid analyte into the head or entrance of a column whereby a stream of an inert gas acts a carrier (mobile phase). The column acts as a separator of individual or chemically similar components.
Range: The data generated in precision and linearity was considered for establishment of Range. The sample weight of 1250 mg to 3750 mg was taken for analysis and it was found to be within the linearity and precise. Robustness: Reliability of the method was done about deliberate variations in method parameters like a. Variation in the flow rate of mobile phase (±0.1 ml/min) b. Variation in cooler temperature (±2 nm)
CLAIRE MUNTING 29/01/2018 Criterion C EFFECTS OF SURFACE AREA OF CALCIUM CARBONATE UPON RATE OF REACTION Calcium Carbonate Chips 1 Introduction: Within the current investigation, the effects of the surface area of Calcium Carbonate (CaCO3) in combination with Hydrochloric acid (HCl) upon its rate of reaction. CaCO3, commonly referred to as limestone, is an organic substance and is, in a sense, the crystallised “carbonic salt” of the element, calcium2. In addition to being a salt, the pH level of Calcium Carbonate is 9.91, and it is therefore, a basic substance, due to the fact that it is comprised of a pH level higher than 7, which is neutral3. HCl, however, is the bodily acid found in the stomach of human beings.
Experiment #1 Isolation of Caffeine from Tea Date: 11.09.14 Prepared by: Alibek Abilev Purpose The aim of the experiment was to isolate crude caffeine from tea leaves by using liquid – liquid extraction with methylene chloride, purify the crude substance by performing sublimation and determine the melting point of both crude and pure caffeine. Safety Lab coat, goggles, gloves. Methylene chloride is a carcinogenic substance, therefore should be kept in a well-ventilated place.
Caffeine is a chemical found naturally in few plants all over the world. From these plants it is processed into its pure form and then put into other things such as soda, energy drinks, tea, and pills. Energy drinks and soda are some of the most widely marketed products in the world, even though they contain the highest concentration of caffeine outside of pure caffeine supplements. It is a stimulant that affects everyone in strange but semi predictable ways. Research has been done on this topic since the 1920’s and many different conclusions have been reached.
Experiment #7: Column Chromatography of Food Dye Arianne Jan D. Tuozo Mr. Carlos Edward B. Santos October 12, 2015 Abstract Column chromatography is the separation of mixture’s components through a column. Before proceeding with the column chromatography itself, a proper solvent system must be chosen among the different solvents. The green colored food dye is the mixture whose components are separated.
Introduction The term chromatography actually means colour writing, and signifies a technique by which the substance to be examined is placed in a vertical glass tube containing an adsorbent, the different segments of the substance traveling through the adsorbent at distinctive rates of velocity, according to their degree of attraction to it, and producing bands of colour at different levels of the adsorption column. The substances least absorbed emerge earliest; those more strongly absorbed emerge later. (Wixom et al., 2011) In chromatography of all types, there is a mobile phase and a stationary phase.
The internal standard method allows a very accurate analysis to be performed, since the behaviour of the species of interest is compared to that of a known substance which is present in a specified amount. It is usual to include an identical volume or mass of the internal standard into each prepared standard. This facilitates easier calculations of the composition of the
Biochemical tests are the tests used for the identification of bacterial species based on the differences in the biochemical activities of different bacteria. Bacterial physiology differs from one species to the other. These differences in carbohydrate metabolism, protein metabolism, fat metabolism, production of certain enzymes and ability to utilize a particular compound help them to be identified by the biochemical tests. Gram’s stain was originally devised by histologist Hans Christian Gram in 1884. Gram-positive bacteria stain purple, while Gram-negative bacteria stain pink when subjected to Gram staining.