...Acis CHEMICAL REACTIONS: ACID-BASE BUFFERS Short Overview Acids and bases represent two of the most common classes of compounds. Many studies have been done on these compounds, and their reactions are very important. Perhaps the most important reaction is the one in which an acid and base are combined, resulting in the formation of water (in aqueous solution) and a salt; this reaction is called neutralization. A buffer solution is a solution that contains both an acid and a salt containing the conjugate base anion in sufficient concentrations so as to maintain a relatively constant pH when either acid or base is added. In this experiment you will prepare a buffer solution and observe its behavior when mixed both with an acid and a base. You will also compare the behavior with that of solutions containing only the acid. Theory In his theory of ionization in the 1880’s, Svante Arrhenius defined acids are substances which form H+ and bases as substances which form OH- in water. He further defined a salt as a substance other than an acid or base which forms ions in aqueous solution. Such substances are thus capable of producing an electric current and are called electrolytes. The amount of electricity produced is directly proportional to the concentration of ions in solution. With regard to electrolytes we have learned previously that strong acids and strong bases ionize completely, and are therefore strong electrolytes because they...
Words: 2786 - Pages: 12
...2.1 Chemicals and buffers 2.1.1 Chemicals Chemicals used were of high molecular biology grade unless specified otherwise. A complete list of chemicals is available in Appendix 1. 2.1.2 Buffers Buffers were prepared with molecular biology grade chemicals. Buffer Composition TE Buffer 10mM Tris-Cl (pH 7.4), 1mM EDTA (pH 8.0) Loading buffer 0.25% bromophenol blue, 40% sucrose TAE Buffer 40mM Tris-acetate, 2mM EDTA 2.2 MEDIA 2.2.1 Great Artesian Basin (GAB) media The medium used for this project was designed to allow the growth of thermophiles and mesophiles that were isolated from the Great Artesian Basin. The media was adjusted to support the growth of both aerobic and anaerobic organisms. The media composition as grams/liter is as follows...
Words: 3778 - Pages: 16
...drugs work or increase the risk of unwanted side effects. 3.2 Analytical methods Various methods are reported in the literature for estimation of ETD in dosage from and for its in-vitro and in-vivo estimation. Among those few are as follows. 3.2.1 Spectroscopic Method 3.2.1.1 Colorimeter and Spectrophotometer (M. Dey et al., 1971) The UV spectrum of ETD in methanol is characterized by maxima at 224 ± 1nm (a= 37970) and 279±1 nm (a = 8440), and a minimum at 246 ± 1nm. The absorbance of the 278 nm or 279 nm peak was used to quantitative the amount of drug dissolved from ETD capsules and sustained release tablets in pH 7.5 phosphate buffer. A colorimetric method for the analysis of ETD has been reported which is based on the formation of colored complexes with p-dimethyl-aminobenzaldehyde in the presence of sulfuric acid and ferric chloride. Absorbance measurements were made at 591.5 nm, and the method was found to be linear over the concentration range 10 to 80µg/ml. This method was used to determine ETD in bulk powder and other dosage forms. 3.2.2 Chromatographic Method 3.2.2.1 Thin Layer Chromatography (Kraml et al., 1971) A TLC method has been developed to determine ETD and its metabolites (6-OH-ETD and 7-OH- ETD) in biological fluids and extracts (before and after enzyme hydrolysis). The method used silica gel plates and hexane-ethyl acetic acid (60:40:2 v/v) and hexane-ethyl acetate (70:30 v/v) solvent systems to separate the free carboxylic acid and methyl esters of ETD...
Words: 981 - Pages: 4
...Chemistry Extended Essay “How does pH affect the concentration of trihalomethanes formed in a sample of reservoir water when it is disinfected with chlorine or chloramine and to what extent do both chloramine and free chlorine decompose when exposed to ultraviolet light?” Abstract This investigation aims to find out how pH affects the concentration of trihalomethanes formed in a sample of reservoir water when it is disinfected with chlorine or chloramine and the extent to which both free chlorine and chloramine decompose when exposed to ultraviolet light. Headspace gas chromatography and mass spectrometry were used to measure the concentration of the four main constituents of total trihalomethanes (TTHMs), namely chloroform,...
Words: 2953 - Pages: 12
...enzyme-substrate complex for a very short time, this then becomes part of a new formation and a new product of a specific reaction is formed then released freeing the active site, allowing the enzyme to repeatedly bind another substrate. Enzymes are produced by all living things, and are a necessity to life. They are responsible for constructing, synthesizing, carrying, dispensing, delivering, and eliminating the many chemicals associated in living organisms (Colpa 2014). An example for how enzymes work in living organisms would be the process of food digestion, enzymes work to break down food and speed up the digestion process. Factors that affect enzyme activity deal with environmental conditions, which are temperature, salt concentration, and also pH concentration. These factors influence or alter the shape of the enzyme, and therefore affect the efficiency of binding with a substrate. Changing any of the factors alters the rate of the reaction caused by the enzyme. In this lab, we studied an enzyme known as peroxidase. All peroxidases are remarkably stable and easy to assay,...
Words: 2496 - Pages: 10
...Biology Lab Fall 2014 Determining the properties of an enzyme Abstract: To determine the properties of an enzyme, a peroxidase, turnip extract is used in this experiment Enzymes are large proteins that are responsible for the speed at which chemical reactions they are involved in taking place. Enzymes speed up chemical reactions by lowering the activation energy of a reaction, the amount of energy necessary to trigger a reaction .Using Peroxidase ,Turnip extract which is expermitnatal easy to prepare and examime that is This experiment determines the effects that concentration temperature, ph, boiling have on an enzymes ability to perform its work. It is hypothesized that none of these variables will have any effect on the activity of the enzyme. Introduction : This expermient with present various temperates and ph levels to be teste in order to determine the properties of an enzyme. An enzyme is a protein that acts as a catalyst, that changes the rate of a reaction with no help of energy. Enzymes lower the activation energy of a reaction the amount of energy necessary to trigger a reaction. Most enzymes are proteins that have a unique shapes which are determined by their amino acid sequences.The shape of the enzyme called the active site determines its catalytic effects. The active site of each type of a unique shape that allows the enzyme to bind with only certain kinds of enzymes called the substrate. Smaller molecules are called...
Words: 1757 - Pages: 8
...J. clin. Path. (1963), 16, 12 The haemolytic activity of an iron carbohydrate complex J. FIELDING with the technical assistance of GILLIAN M. SMITH From Paddington General Hospital, London The haemolytic activity of iron-dextran complex is found to be a function of time, temperature, pH, and concentration. The lytic action is enhanced by small amounts of added ferrous sulphate. The lytic action is inhibited by chelating agents such as citrate and sequestrene salts, which bind ionic iron, but not by ferric citrate or ferric sequestrene which do not bind iron. The ionised iron content of iron-dextran is deduced. SYNOPSIS The lytic activity of iron-dextran is also inhibited by iron-dextrin and by an iron-sorbitol-citric acid preparation. It is suggested that the iron-sorbitol-citrate molecular complex contains free chelating groups for iron. The significance of these findings for iron-carbohydrate toxicity and metabolism is briefly discussed. The clinical toxicity of parenteral iron preparations, both intravenous and intramuscular, has been one of the principal problems associated with their use. The toxic manifcstations are varied in kind and tend to form a pattern of reactions characteristic in type for each iron complex. It is unlikely that a single factor is responsible for all or even most of the observed toxic reactions. Instability of the complex in plasma with possible precipitation in vivo is a likely cause in the case of the saccharated...
Words: 3885 - Pages: 16
...Title of Experiment 9: Measurement of Nucleic Acid Solutions Objectives: 1. To study the principle of gel electrophoresis. 2. To use gel electrophoresis method to measure the nucleic acid solutions. 3. To learn the technique of nuclei acid measurement by using gel electrophoresis. Introduction: Gel electrophoresis is a widely used technique for the analysis of nucleic acids and proteins. Most every molecular biology research laboratory routinely uses agarose gel electrophoresis for the preparation and analysis of DNA. The components of gel electrophoresis system is power supply and a chamber, agarose gel which is a porous material that allows molecules migrate through, buffer with a mixture of water and ions, and gel casting tray and comb. Electrophoresis is a method of separating substances based on the rate of movement while under the influence of an electric field. Agarose is a polysaccharide purified from seaweed. An agarose gel is created by suspending dry agarose in a buffer solution, boiling until the solution becomes clear, and then pouring it into a casting tray and allowing it to cool. The result is a flexible gelatin-like slab. Nucleic acids are composed of chains of nucleotides. The ‘backbone’ of the nucleic acid structure is a repeating chain of phosphate groups and pentose sugars. At certain pH values, the oxygen atoms in the phosphate groups ionize, giving the molecule an overall negative charge. If exposed to an electric field, these molecules are attracted...
Words: 1470 - Pages: 6
...Biotechnology is a field of applied biology that involves the use of living organisms and bioprocesses in engineering, technology, medicine and other fields requiring bio products. Father of the term biotechnology is ‘Karl Ereky’ and Father of Biotechnology was ‘Louis Pasteur’. DNA, or deoxyribonucleic acid, is the hereditary material in humans and almost all other organisms. Nearly every cell in a person’s body has the same DNA. Ribonucleic acid or RNA, is one of the three major macromolecules (along with DNA and proteins) that are essential for all known forms of life. A pipette (also called a pipet, pipettor or chemical dropper) is a laboratory instrument used to transport a measured volume of liquid. Pipettes come in several designs for various purposes with differing levels of accuracy and precision, from single piece glass pipettes to more complex adjustable or electronic pipettes. Lab dish washing Cleaning laboratory glassware isn't as simple as washing the dishes. Here's how to wash your glassware so that you won't ruin your chemical solution or laboratory experiment. You can rinse the glassware with the proper solvent, then finish up with a couple of rinses with distilled water, followed by final rinses with deionized water Water Soluble Solutions (e.g., sodium chloride or sucrose solutions) Rinse 3-4 times with deionized water then put the glassware away. Water Insoluble Solutions (e...
Words: 1488 - Pages: 6
...BIOL 3380 Name:_____________________________________ Circle Session: T-PM W-AM W-PM R-AM R-PM F-AM F-PM Experiment 9 – Pre-lab Homework Enzyme Kinetics of LDH This pre-lab homework assignment is due at the beginning of your lab session. You are provided with the following portion of a protocol: • Determine concentration of enzyme stock solution, if unknown, by taking an A280 nm reading of a 1:100 dilution (in water). Use a total volume of 1 ml in the cuvette. • Dilute some of the enzyme stock with buffer A to make a 4 mg/ml solution. • Serially dilute the 4 mg/ml solution with buffer A to make working solutions of 400 µg/ml and 40 µg/ml. • Prepare 30 µl of each working solution for every sample The PI of the lab gives you a tube of enzyme and tells you the following before disappearing into the office to write more grant proposals: ➢ There is 50 µl of enzyme stock solution. The enzyme is expensive to purify, so follow the protocol exactly, using as little of the stock solution as possible. ➢ The concentration of the stock solution is currently not known, but a 1 mg/ml concentration of the pure enzyme has an A280 nm of 2.0. ➢ You’ll be performing the assay on 12 samples. ➢ Make enough of each working solution so that you have at least 400 ul to work with when you do the assay (to cover any waste and/or inefficiencies in pippetting). Using the spectrophotometer to read the absorbance at 280 nm, you get...
Words: 3629 - Pages: 15
...FORMULATION AND EVALUATION OF TOPICAL GEL CONTAINING AZITHROMYCIN AND PREDNISOLONE VESICLES FOR TREATING PSORIASIS Sonia Tomar, Tinku Singhal, ABSTRACT Psoriasis is a chronic, autoimmune systemic inflammatory disease, associated with metabolic syndrome, cerebrovascular disease, diabetes and many other diseases. There is various type of psoriasis but most common type of psoriasis is caused by Psoriasis vulgaris. It is characterized by rigid of skin due to increase in the level of cholesterol and fall in the level of ceramide. Apart from that it is associated with an immune system of the body means movement of immune cells from dermis to the epidermis, where they stimulate skin cells (keratinocytes) to proliferate. Various type of drug delivery system are used for the treatment of psoriasis including topical, oral or systemic but gels prepration of azithromycin and prednisolone are more effective in reduction of purities, scaling and hyperkeratosis of psoriasis plaque. Niosomal/Vesicular gel, has been explored extensively for topical application to enhance skin penetration as well as skin retention. Prednisolone and azithroycin together provide effective results in the treatment of psoriasis. Due to high entrapment efficiency and stability, gel prepration (Azithromycin & Prednisolone) reduce the scaly patches and suppression of humoral immunity. Keywords: Niosome, Immunity, Topical, Psoriasis, Gel, Azithromycin, Prednisolone. INTRODUCTION Psoriasis is recognized...
Words: 7354 - Pages: 30
...SERV ICE & SUPPORT PRINTED IN USA. Revised 6/11 Part# TM040 Dual-Luciferase® Reporter Assay System All technical literature is available on the Internet at: www.promega.com/tbs/ Please visit the web site to verify that you are using the most current version of this Technical Manual. Please contact Promega Technical Services if you have questions on use of this system. E-mail: techserv@promega.com. 1. Description..........................................................................................................2 A. Dual-Luciferase® Reporter Assay Chemistry...................................................3 B. Format of the Dual-Luciferase® Reporter Assay .............................................5 C. Passive Lysis Buffer .............................................................................................6 2. Product Components and Storage Conditions ............................................8 3. The pGL4 Luciferase Reporter Vectors .........................................................9 A. Description of pGL4 Vectors ..............................................................................9 B. Important Considerations for Co-Transfection Experiments ........................9 4. Instrument Considerations ............................................................................10 A. Single-Sample Luminometers...........................................................................10 B. Multi-Sample and Plate-Reading Luminometers...
Words: 9055 - Pages: 37
...EXPERIMENT 1 DETERMINATION OF DISSOLVED OXYGEN IN WATER INTRODUCTION The dissolved oxygen content is an important index when considering its suitability for town supply. A good clean potable water will give dissolved oxygen value close to the theoretical value for the saturated solution of oxygen in water. When there is pollution from organic matter and other trade effluents, the dissolved oxygen is up in various biochemical oxidation processes and its is only slowly replaced through surface absorption. Such water will give a low dissolved oxygen content until oxidation is completed. Adequate dissolved oxygen is necessary for the life of fish and other aquatic organisms. The methods described below for the determination of oxygen in water is based on that devised by Winkler. When manganese hydroxide is precipitated in the water sample it is quickly oxidized to higher hydrated oxides (probably in the four valent state) by the dissolve oxygen. Iodine, equivalent to the dissolved oxygen content, is then liberated on acidification in the presence of iodine, and it may be titrated with standard thio‐sulphate. INTERFERENCES AND PRE – TREATMENT Most oxidising and reducing substances e.g dissolved organic substances, nitrite ions, higher‐valency manganese compounds, active chlorine, sulphide and sulphite ions, iron (II) and irons interfere. The influence of the dissolved organic substances can be excluded by conversion of the manganese hydroxides...
Words: 6038 - Pages: 25
...Detection : 275nm Flow rate : 2ml/min Injection volume : 20µl Column Temperature: 25oC Run Time : 25min Mobile phase preparation It is prepared by mixing 800ml of Tetrahydrfuran and 1200ml of water mixed and filtered. Preparation of Diluent It is prepared by diluting 68ml of water with Isopropyl Alcohol to 1000ml Preparation of Standard stock solution Weighed 20.95mg of propofol standard and transferred to 25ml of volumetric flask. Add 10ml of diluent, sonicate to dissolve and make up the volume with diluent. Preparation of Sample preparation Transfer 2ml of sample solution into 25ml of volumetric flask. Add 10ml of diluent, sonicate to dissolve and make up the volume with diluent Procedure: Inject blank(inj)(diluent) and standard preparation(5inj) Check for the following system suitability parameters The relative std deviation for replication inj is not more than 1.5% If the system suitability parameters pass, then inject Assay preparation(2inj) and report the chromatograms CALCULATIONS: Calculate the quantity in % of propofol in each ml of inj taken by the formulation. Qty of Propofol in % = AT/AS × WS/DS × DT/V × 100/LC...
Words: 1481 - Pages: 6
...4110065A.qxp 9/25/2007 2:39 PM Page 1 ™ Quick Start Bradford Protein Assay Instruction Manual For technical service call your local Bio-Rad office, or in the US, 1-800-4BIORAD (1-800-424-6723) 4110065A.qxp 9/25/2007 2:39 PM Page 5 Table of Contents Section 1 Introduction 1 1.1 Principle 1 1.2 Selecting a Protein Standard 5 1.3 Product Description Section 2 Instructions 9 11 2.1 Standard Assay Protocol 11 2.2 Microassay Protocol 14 Section 3 Data Analysis 18 Section 4 FAQs and Troubleshooting 22 Section 5 Ordering Information 26 Section 6 References 28 Section 7 Appendix 30 4110065A.qxp 9/25/2007 2:39 PM Page 7 Section 1 Introduction The Quick Start Bradford protein assay is a simple and accurate procedure for determining the concentration of protein in solution. It provides ready-to-use convenience by supplying the dye reagent at 1x concentration and two protein assay standards at seven prediluted concentrations. The prediluted standards are conveniently packaged in 2 ml screwcap vials, eliminating wasteful and sharp ampoules, and ensuring protein stability over the shelf life of the product. 1.1 Principle The Bradford assay is a protein determination method that involves the binding of Coomassie 1 4110065A.qxp 9/25/2007 2:39 PM Page 8 Brilliant Blue G-250 dye to proteins (Bradford 1976). The dye exists in three...
Words: 4025 - Pages: 17
