Rapid Determination of Ionization Constants (pk a ) by UV Spectroscopy Using 96-well Microtiter Plates
|
|
- Candace Gordon
- 5 years ago
- Views:
Transcription
1 Supporting Information Rapid Determination of Ionization Constants (pk a ) by UV Spectroscopy Using 96-well Microtiter Plates Carlos H. Ríos Martínez and Christophe Dardonville * Instituto de Química Médica, IQM-CSIC, Juan de la Cierva, E 86 Madrid, Spain. Table of contents: ) Preparation of buffer solutions S ) Experimental procedure S5 ) Data analysis S7 ) Spectra and pk a determination plots for compounds 8 S8 S
2 ) Preparation of buffer solutions The of the buffers was measured with a glass electrode (HANNA HI- meter) at ºC. All the solutions were prepared with distilled water. The. M standard solution of HCl was titrated with K CO (C =.8 M). The. M standard solution of NaOH was sonicated during min and titrated with potassium phthalate (C =. M). The ionic strength of each buffer solution was calculated using equation and the amount of KCl needed to adjust the ionic strength to. M was calculated for each buffer (Table S). () where c i is the molar concentration of ion i, z i is the charge number of that ion, and the sum is taken over all ions in the solution. a) Acetic acid/sodium acetate buffers (AcOH/AcONa) covering the range. to 5.. ml of. M sodium acetate solution was prepared by dissolving sodium acetate (8. mg, mmol) in ml of distilled water. 5 ml of each buffer solution (.,. and 5.) was prepared as follows: 5 ml of. M sodium acetate solution was stirred at ºC. The was adjusted to the required value by adding. M HCl standard solution with a burette. The volume was adjusted to 5 ml with distilled water. Finally, the ionic strength of the buffer solutions was calculated using equation and adjusted to. M by adding KCl (see Table ). S
3 b) Potassium hydrogen phosphate/dipotassium hydrogen phosphate (KH PO /K HPO ) buffers covering the range 6. to 8.. L of 5 M potassium hydrogen phosphate solution was prepared by dissolving KH PO (6.8 g, 5 mmol) in L of distilled water. 5 ml of each buffer solution ( 6. to 8.) was prepared as follows: 5 ml of. M KH PO was stirred at ºC in an erlenmeyer flask. The was adjusted to the required value by adding. M HCl or. M NaOH standard solution with a burette. The volume was adjusted to 5 ml with distilled water. The ionic strength calculated for these buffer solutions (Eq ) were in the range 7 68 M. Hence, the ionic strength was adjusted to. M by adding the necessary quantity of KCl (see Table S). c) Sodium tetraborate decahydrate (Borax)/boronic acid (Na B O 7 /H BO ) buffers covering the range 8. to.8 L of 5 M borax solution was prepared by dissolving borax decahydrate (9.5 g, 5 mmol) in L of distilled water. 5 ml of each buffer solution ( 8. to 9.) was prepared as follows: 5 ml of 5 M borax solution was stirred at ºC. The was adjusted to the required value by adding. M HCl. The volume was adjusted to 5 ml with distilled water. The ionic strength calculated for these buffer solutions were in the range of 5 6 M. Hence, the ionic strength was adjusted to. M by adding the necessary quantity of KCl (see Table S). 5 ml of each buffer solution ( 9. to.8) was prepared using 5 ml of 5 M borax (Na B O 7.H O) stirred at ºC. The was adjusted to the required value by adding. M NaOH. Finally, the ionic strength was adjusted to. M by adding KCl (See Table Sl). S
4 d) Disodium hydrogen phosphate/sodium phosphate (Na HPO /Na PO ) buffers covering the range.9 to. L of 5 M disodium hydrogen phosphate solution was prepared by dissolving Na HPO (7.98 g, 5 mmol) of in L of distilled water. 5 ml of a solution of 5 M Na HPO was stirred at ºC. The was adjusted to the required value by adding. M NaOH. The volume was adjusted to 5 ml with distilled water. The ionic strength calculated for these buffer solutions were in the range M. Hence, the ionic strength was adjusted to. M by adding the necessary quantity of KCl (see Table ). e) Glycine/NaOH buffer (.6) This buffer was commercially available (Fluka 55). Table S. Preparation of buffer solutions of constant ionic strength (I =. M) buffer Target Measured Conc. of salt solution (M) Vol. of salt solution (ml) Vol. of. M* HCl (ml) Vol. of. M** NaOH (ml) Vol. H O (ml) Calculated Ionic strength (M) Conc. of KCl required (M) Mass of KCl (mg) NaOAc/HOAc KH PO /K HPO Borax Na HPO /Na PO * C =.8 M ** C =. M S
5 ) Experimental procedure A small quantity ( mg) of each compound was weighted in an eppendorf tube using a high precision analytical balance (Mettler Toledo XS5). The compound was dissolved in DMSO to a concentration of mm (stock solution). The UV transparent 96-well microplate (Thermo Scientific Nunc) was loaded as shown in Figure S: each line of the plate was loaded with 96 µl of buffer solutions of increasing ( ranging from to.6). Then, µl of the compound stock solutions were added to each well with a micropipette (the resulting analyte solution was premixed with the micropipette). The final concentration of the analyte compound in each well was µm. One blank solution was prepared for each buffer by adding µl of DMSO to 96 µl of the corresponding buffer solution (i.e., free of analyte compounds) in the well. The 96-well plate was loaded into the UV-spectrophotometer (THERMO Multiskan Spectrum apparatus), incubated at ºC and shaken for min before the reading was performed. UV-spectra scans were recorded between nm and nm ( nm resolution). It should be noted that the number and range of buffer solutions needed to determine the pk a (e.g., every., or units) was adjusted depending on the compound tested. In general, a first screening with buffers ranging from to should give an approximate pk a value which can be refined when repeating the experiment using buffers within ± units of the pk a value. S5
6 Figure S. Example of loading of the 96-wells microtiter plate Buffer ( 96 µl) Buf f er : Compound ( µl) Compound ( µl) Compound ( µl) Compound ( µl) Compound 5 ( µl) Compound 6 ( µl) Compound 7 ( µl) Blank: DMSO ( µl) S6
7 ) Data Analysis In the present study we have used a similar data analysis as described by Tomsho et al. for the determination of ionization constants by spectral analysis. The raw UV-spectra scans were imported to the Excel program and processed as follows: ) UV-spectra of the analyte compounds were corrected by subtracting the UVspectra of the blank solutions; ) The raw scans were normalized (Abs nm = ); ) The spectral difference between the acid spectra and the spectra at every other was plotted; ) The wavelengths of maximum positive and negative absorbance were determined graphically from the spectral difference plot; 5) The total absorbance difference at the chosen wavelengths (that is: the sum of the absolute values of the maximum positive and negative absorbance in the spectral difference plot) was plotted against the. 6) These data were imported to the Prism program and the pk a values were worked out by non linear regression using equation : total = ε ΗΑ ε Α [ ( pka ) ] + ( pka ) * [ S t] Eq. ε HA and ε A - are the extinction coefficients of the acid and base forms of the compound, respectively (i.e., the minima and maxima of the absorbance difference curve, respectively), and [S t ] is the total compound concentration. S7
8 ) Spectra and pk a determination plots for compounds 8 o -Methylbenzimidazole (). -Methylbenzimidazole () Methylbenzimidazole () Methylbenzimidazole () 68 nm 78 nm 6 8 Difference. -Methylbenzimidazole () 6 8 o 5-Nitro-H-imidazole () 5-Nitro-H-imidazole () Nitro-H-imidazole () Nitro-H-imidazole () 9 nm 5 nm Difference. 5-Nitro-H-imidazole () 6 8 S8
9 o Clonidine ().5. Clonidine () Clonidine (). - nm Clonidine () nm 5 5 Difference Clonidine () 6 8 o Oxybis(,-phenylene) dicarbamimidate (5).5. (5) (5) - (5) 5 nm 9 nm Difference (5) 6 8 S9
10 o Compound 6a (6a) (6a) - - (6a) 58 nm 8 nm Difference.5. (6a) 6 8 o Compound 6b (6b) (6b) (6b) (6b) - 58 nm nm Difference 6 8 S
11 o Compound 6c 5 - (6c) (6c) - - (6c) 6 nm nm Difference.5. (6c) 6 8 o Compound 6d (6d) (6d) (6d) 6 nm - - nm Difference.5. (6d) 6 8 S
12 o Compound 7a (7a) (7a) - - (7a) 6 nm nm Difference. (7a) 6 8 o Compound 7b (7b) (7b). - (7b) 6 nm 6 nm Difference.5. (7b) 6 8 S
13 o Compound 7c (7c) (7c) - - (7c) 6 nm 6 nm Difference. (7c) 6 8 o Compound 7d (7d) (7d) nm (7d) 6 nm Difference. (7d) 6 8 S
14 o Compound 8a (8a) (8a) - - (8a) 6 nm 9 nm 5 5 Difference (8a) 6 8 o Compound 8b (8b) (8b) - - nm (8b) Spectral difference plot 7 nm 5 5 Difference (8b) 6 8 S
15 o Compound 8d (8d) (8d) - - (8d) 96 nm 58 nm 5 5 Difference. (8d) 6 8 References. Tomsho, J. W.; Pal, A.; Hall, D. G.; Benkovic, S. J. Ring Structure and Aromatic Substituent Effects on the pka of the Benzoxaborole Pharmacophore. ACS Med. Chem. Lett.,, 8-5. S5
AIM To verify Beer - Lambert s law and to determine the dissociation constant (Ka) of methyl red, Spectrophotometrically.
C 141(Expt. No. ) NAME : ROLL No. : SIGNATURE : BATCH : DATE : VERIFICATION OF BEER - LAMBERT S LAW & DETERMINATION OF DISSOCIATION CONSTANT (Ka) OF METHYLRED, SPECTROPHOTOMETRICALLY AIM To verify Beer
More informationDetermination of the Equivalent Weight and Ionization Constant of a Weak Acid
Determination of the Equivalent Weight and Ionization Constant of a Weak Acid Introduction: The object of this experiment will be to determine the ionization constant, K a, and the equivalent weight of
More informationPartner: Alisa 1 March Preparation and Properties of Buffer Solutions
Partner: Alisa 1 March 2012 Preparation and Properties of Buffer Solutions Purpose: The purpose of this experiment is to compare the ph effect on buffered and non-buffered solutions as well as making a
More informationBCH312 [Practical] 1
BCH312 [Practical] 1 Triprotic acid is acid that contain three hydrogens ions. It dissociates in solution in three steps, with three Ka values. phosphoric acid is an example of triprotic acid. It dissociates
More informationEXPERIMENTAL DETAILS
EXPERIMENTAL DETAILS - 32 - 2.1 Preparation Of Solutions:- For the present work all the the solvents, Reagent and chemicals used were of Sdfine / Riedel Make. The purity of the chemicals and reagents were
More informationCHEMISTRY LABORATORY - I
The Great Chemist ALFRED NOBEL CHEMISTRY LABORATORY - I -1- WORK SHEET Titration 1 : Standardization of AgNO 3 Standard Sodium chloride Vs AgNO 3 Sl.No Vol.of Sodium chloride V 1 (ml) Burette reading (ml)
More informationPRACTICAL 3 ph AND BUFFERS
PRACTICAL 3 ph AND BUFFERS ph and Buffers Structure 3.1 Introduction 3.2 ph and Buffers: Basic Concept 3.2.1 ph 3.2.2 Buffers and Buffer Solutions 3.3 Methods for Determining ph Experiment 1: Measurement
More informationBuffers and chemicals
Buffers and chemicals A. Commonly Used Buffers Buffer Synonyms pk Molecular weight Phosphate (pk 1 ) 2.12 98.0, free acid Glycine-HCl 2.34 111.53 Citrate (pk 1 ) 3.14 192.1, free acid Formate 3.75 68.0,
More informationDetermination of the Equilibrium Constant. HIn - + H 2 O = H 3 O + + In 2-, [H 3 O + ][In 2- ] K ai = [HIn - ]
Determination of the Equilibrium Constant Introduction Indicators are substances whose solutions change color due to changes in ph. They are usually weak acids or bases, but their conjugate base and acid
More informationChemistry Determination of Mixed Acids
Chemistry 3200 Acid-base titration is one of the most common operations in analytical chemistry. A solution containing an unknown amount of ionizable hydrogen can be titrated with a solution of standard
More informationTextiles - Determination of ph of Aqueous Extract
Translated English of Chinese Standard: GB/T7573-2009 www.chinesestandard.net Sales@ChineseStandard.net ICS 59. 080. 01 W 04 NATIONAL STANDARD GB OF THE PEOPLE'S REPUBLIC OF CHINA GB/T 7573-2009 Replacing
More informationPractical Note BIOCHEMICAL CALCULATIONS (BCH 312)
I II 2011 King Saud University College of Science kingdom of Saudi Arabia Ministry of Higher Education king Saud University College of Science Practical Note BIOCHEMICAL CALCULATIONS (BCH 312) Prepared
More informationCEE 684 (697K) Dichloropropanone Lab
CEE 684 (697K) Dichloropropanone Lab Laboratory Project Work in groups of three to investigate the kinetics of reaction between aqueous chlorine and 1,1-dichloropropanone (DCP). Use the paper by Guthrie
More informationElectronic Supplementary Information
Electronic Supplementary Information Multicomponent Hydrogels from Enantiomeric amino acid derivatives: Helical Nanofibers, Handedness and Self-Sorting Bimalendu Adhikari, Jayanta Nanda and Arindam Banerjee*
More information1 st European Union Science Olympiad in Dublin, Ireland. task B
1 st European Union Science Olympiad in Dublin, Ireland task B Task B The Properties of Proteins Introduction In this task you will investigate some of the properties of proteins. Proteins consist of a
More informationExperiment 7 Buffer Capacity & Buffer Preparation
Chem 1B Dr. White 57 Experiment 7 Buffer Capacity & Buffer Preparation Objectives To learn how to choose a suitable conjugate acid- base pair for making a buffer of a given ph To gain experience in using
More informationLast Semester: Titration of a weak acid (vinegar) with a strong base. NaOH. Equivalence (End) Point. mols NaOH = mols Acid.
// VIRTUAL LAB & IDENTIFICATION OF AN UNKNOWN WEAK ACID RFS / Purpose: To conduct a titration, to use it to determine the Molar Mass and pk a of an unknown acid & from these two quantities, identify of
More informationPreparation Of Buffer Solutions By Different Laboratory Ways. BCH 312 [Practical]
Preparation Of Buffer Solutions By Different Laboratory Ways BCH 312 [Practical] Dissociation of Triprotic acid Triprotic acid is acid that contain three hydrogens ions. It dissociates in solution in three
More informationTable of Contents. Purpose... 2 Background... 2 Prelab Questions... 3 Procedure:... 3 Calculations:... 4
Table of Contents Purpose... 2 Background... 2 Prelab Questions... 3 Procedure:... 3 Calculations:... 4 CHM 212 Experiment 4 Determination of the Ka of Potassium Hydrogen Phthalate (KHP) Using a Gran Plot
More informationCertificate of Analysis
Certificate of Analysis 10 Old Barn Road Lake Placid, NY 12946 Technical Support: T: 800 548-7853 F: 518 523-4513 email: techserv@upstate.com Sales Department: T: 800 233-3991 F: 781 890-7738 Licensing
More informationThermodynamics of Borax Dissolution
Thermodynamics of Borax Dissolution Introduction In this experiment, you will determine the values of H, G and S for the reaction which occurs when borax (sodium tetraborate octahydrate) dissolves in water.
More informationAnalyte: The substance whose concentration is not known in a titration. Usually the analyte is in the flask or beaker beneath the burette.
Key Worksheet 15 Acids & Base Equilibria: Acid Base Titrations Objectives To be able to calculate the ph, poh, and concentrations of all species present at any point of an acid base titration. Vocabulary
More informationEXPERIMENT 14. ACID DISSOCIATION CONSTANT OF METHYL RED 1
EXPERIMET 14. ACID DISSOCIATIO COSTAT OF METHYL RED 1 The acid dissociation constant, Ka, of a dye is determined using spectrophotometry. Introduction In aqueous solution, methyl red is a zwitterion and
More informationFirst week Experiment No.1 / /2013. Spectrophotometry. 1. Determination of copper via ammine complex formation using standard series method
First week Experiment No.1 / /2013 Spectrophotometry 1. Determination of copper via ammine complex formation using standard series method Principal In the standard series method the teat and standard solution
More information5 Acid Base Reactions
Aubrey High School AP Chemistry 5 Acid Base Reactions 1. Consider the formic acid, HCOOH. K a of formic acid = 1.8 10 4 a. Calculate the ph of a 0.20 M solution of formic acid. Name Period Date / / 5.2
More informationANALYTICAL METHOD PROCEDURES
HPLC ASSAY AND RELATED SUBSTANCE Column Eurospher 100, C18, 25 x 0.40 cm 5µ Mobile Phase Buffer ph 2.0*: Acetonitrile (88:12 v/v) * Buffer ph 2 Potassium dihydrogen phosphate (KH 2 PO 4 ) - 0.68g Hepatane
More informationIn vivo monitoring of hydrogen sulfide using a cresyl violet-based ratiometric fluorescence probe
Electronic Supplementary Information for: In vivo monitoring of hydrogen sulfide using a cresyl violet-based ratiometric fluorescence probe Qiongqiong Wan, Yanchao Song, Zhao Li, Xinghui Gao and Huimin
More informationThe texts, tables and images contained in this lecture notes are not my own, they can be found on: References supplied
The texts, tables and images contained in this lecture notes are not my own, they can be found on: References supplied Atlases or The web sites Source: http://www.science.smith.edu/departments/biochem/biochem_353/buffer_pre
More informationCHEM 254 EXPERIMENT 9. Chemical Equilibrium-Colorimetric determination of equilibrium constant of a weak acid
CHEM 254 EXPERIMENT 9 Chemical Equilibrium-Colorimetric determination of equilibrium constant of a weak acid For a weak acid that can only partly dissociate the equilibrium constant is related to activities
More informationAP CHEMISTRY NOTES 10-1 AQUEOUS EQUILIBRIA: BUFFER SYSTEMS
AP CHEMISTRY NOTES 10-1 AQUEOUS EQUILIBRIA: BUFFER SYSTEMS THE COMMON ION EFFECT The common ion effect occurs when the addition of an ion already present in the system causes the equilibrium to shift away
More informationEXPT. 4 DETERMINATION OF pka OF ORTHOPHOSPHORIC ACID
EXPT. DETERMINATION OF pka OF ORTHOPHOSPHORIC ACID Structure.1 Introduction Objectives.2 Principle.3 Requirements. Solutions Provided.5 Procedure.6 Observations and Calculations.7 Result.1 INTRODUCTION
More informationAppendix: 1. Sodium bicarbonate 0.84 gm (10 mm/l) 50ml of 2% sodium carbonate in 0.10N sodium hydroxide
Appendix: 1 Chemicals, Reagents and Buffers 1. BUFFERS FOR WBC EXTRACTION WBC lysis buffer (for 1 liter) Ammonium chloride 8.3 gm (150 mm/l) Sodium bicarbonate 0.84 gm (10 mm/l) 1 X reagent EDTA 29 mg
More information#13 ph-titration of Weak Acids with Strong Bases
#13 ph-titration of Weak Acids with Strong Bases Purpose: A weak acid solution is titrated with a strong base solution. A titration curve is then used to identify the unknown acid and to find its concentration.
More informationph Titration of H 3 PO 4 Mixtures Calculation of K 1, K 2, and K 3
ph Titration of H 3 PO 4 Mixtures Calculation of K 1, K 2, and K 3 Purpose In this experiment the titration of pure H 3 PO 4 and H 3 PO 4 with HCl or NaH 2 PO 4 is followed by measuring the ph of the solution
More informationCHAPTER - 3 ANALYTICAL PROFILE. 3.1 Estimation of Drug in Pharmaceutical Formulation Estimation of Drugs
CHAPTER - 3 ANALYTICAL PROFILE 3.1 Estimation of Drug in Pharmaceutical Formulation 3.1.1 Estimation of Drugs ANALYTICAL PROFILE 84 3.1 ESTIMATION OF DRUG IN PHARMACEUTICAL FORMULATION. Agrawal A et al
More informationExperiment 3: Acids, Bases, and Buffers
Experiment 3: Acids, Bases, and Buffers Reading: Chemistry the Central Science, Chapter 16.1-16.7 Introduction: The reaction of an acid and a base is a neutralization reaction. The technique of accurately
More informationph calculations MUDr. Jan Pláteník, PhD Brønsted-Lowry concept of acids and bases Acid is a proton donor Base is a proton acceptor
ph calculations MUDr. Jan Pláteník, PhD Brønsted-Lowry concept of acids and bases Acid is a proton donor Base is a proton acceptor HCl(aq) + H 2 O(l) H 3 O + (aq) + Cl - (aq) Acid Base Conjugate acid Conjugate
More informationCu-Creatinine- Metol system
Quantification of Creatinine in Human Serum using Metol as a Chromogenic Probe Materials and methods 6.1. Reagents 6.1.1. N-methyl-p-aminophenol sulfate N-methyl-p-aminophenol sulfate also denoted as Metol
More informationChapter 17 Additional Aspects of Aqueous Equilibria (Part A)
Chapter 17 Additional Aspects of Aqueous Equilibria (Part A) What is a dominant equilibrium? How do we define major species? Reactions between acids and bases 1. Strong Acids + Strong Base The reaction
More informationWe need to find the new concentrations of the species in this buffer system. Remember that we also DILUTED the solution by adding 5.0 ml of the HCl.
164 Take 100. ml of the previous buffer (0.05 M tris / 0.075 M tris-hcl), and add 5.0 ml of.10 M HCl. What is the ph of the mixture? The HCl reacts with the tris base, converting it to tris-hcl We need
More information8/2/2017. IDENTIFICATION OF AN UNKNOWN WEAK ACID by ph Titration TEST EXERCISE (105 points) TEST EXERCISE 105 POINTS. PH Titration YOU MUST FINISH
//1? IDENTIFICATION OF AN UNKNOWN WEAK ACID by Titration TEST EXERCISE ( points) [HA] = [A - ] 1 1 TITRATION OF SA AND ASA WITH NaOH vs VOLUME OF NaOH ADDED mg SA VOLUME OF ADDED NaOH TEST EXERCISE POINTS
More informationExperiment 1 (Part A): Plotting the Absorption Spectrum of Iron (II) Complex with 1,10- Phenanthroline
Experiment (Part A): Plotting the Absorption Spectrum of Iron (II) Complex with,0- Phenanthroline Background The first step of an analytical spectrophotometric procedure for quantitative determination
More informationEXPT 11. pk a of ph Indicators
EXPT 11. pk a of ph Indicators [Key Contents] - acid dissociation constant, pk a - buffer, Henderson-Hasselbalch equation - spectrophotometry, Beer's law - ph indicator [References] Principles of Modern
More informationa) most likely to gain two electrons Br O Al Mg b) greatest tendency to form a negative ion Na Li S Mg c) a non-metal Sr S Al K
1. (4 pts) Name the following compounds: Al 2 (SO 4 ) 3 N 2 O 3 2. (4 pts) Give the chemical formulas for the following compounds: chromium (III) carbonate magnesium phosphate 3. (16 pts) Circle the formula
More informationUnderstanding the shapes of acid-base titration curves AP Chemistry
Understanding the shapes of acidbase titration curves AP Chemistry Neutralization Reactions go to Completion Every acidbase reaction produces another acid and another base. A neutralization reaction is
More informationMalachite Green Phosphate Detection Kit Catalog Number: DY996
Malachite Green Phosphate Detection Kit Catalog Number: DY996 This Malachite Green Phosphate Detection Kit employs a simple, sensitive, reproducible, and non-radioactive method for measuring inorganic
More information# 12 ph-titration of Strong Acids with Strong Bases
# 12 ph-titration of Strong Acids with Strong Bases Purpose: A strong acid solution is titrated with a strong base solution. A titration curve is then used to determine the endpoint and find the concentration
More informationA ratiometric fluorescent probe for specific detection of cysteine over. homocysteine and glutathione based on the drastic distinction in the
Supporting Information for A ratiometric fluorescent probe for specific detection of cysteine over homocysteine and glutathione based on the drastic distinction in the kinetic profiles Lin Yuan, Weiying
More informationChapter 2. Materials and Methods
Chapter 2 Materials and Methods 2. Materials and Methods This chapter describes the chemicals, reagents and instruments used for carrying out this study. A brief discussion of the methods used for the
More informationCalibration of a ph Meter and Gravimetric Titrations. by Professor David Cash. September, 2008
CHEMICAL, ENVIRONMENTAL, AND BIOTECHNOLOGY DEPARTMENT Calibration of a Meter and Gravimetric Titrations by Professor David Cash September, 2008 Mohawk College is the author and owner of these materials
More informationExperiment 8 and 9 Weak Acids and Bases: Exploring the Nature of Buffers
Experiment 8 and 9 Weak Acids and Bases: Exploring the Nature of Buffers Pre-Laboratory Assignments Reading: Textbook Chapter 16 Chapter 17:1-3 This Laboratory Handout Pre-Laboratory Assignments: Complete
More informationNational standard of People s Republic of China
National standard of People s Republic of China GB 5413.22 2010 National food safety standard Determination of phosphorus in foods for infants and young children, milk and milk products Issued on 2010-03-26
More informationThis lab will be conducted in groups but the lab report must be completed and submitted individually.
CHM 106 Potentiometric Titration of Phosphoric Acid BACKGROUND Potentiometric titrations are a useful method of determining unknown concentrations in many different types of chemical systems. They may
More informationEXAM 2 CHEMISTRY 224 March 1, Use a #2 pencil to code all information on the answer sheet.
1. Read the following instructions carefully EXAM CHEMISTRY March 1, 01. Write your name and Purdue ID number on the answer sheet 3. Write your Graduate Instructor s name on the line for Instructor on
More informationBioengineering Laboratory I. Enzyme Assays. Part II: Determination of Kinetic Parameters Fall Semester
Bioengineering Laboratory I Enzyme Assays Part II: Determination of Kinetic Parameters 2016-2017 Fall Semester 1. Theoretical background There are several mathematical models to determine the kinetic constants
More informationThermodynamics and the Solubility of Sodium Tetraborate Decahydrate
Thermodynamics and the Solubility of Sodium Tetraborate Decahydrate In this experiment you, as a class, will determine the solubility of sodium tetraborate decahydrate (Na 2 B 4 O 7 10 H 2 O or Na 2 [B
More informationPreparation of a Coordination Compound. Step 1 Copy the balanced equation for the preparation of FeC 2 O 4.. 3H2 O from FeC 2 O 4. Mass of watch glass
Student Name Lab Partner Demonstrator Lab Section DATA SHEET Marking scheme Prelab exercise Lab performance Sig figs, units Calculations Crystals Preparation of a Coordination Compound Step 1 Copy the
More informationChapter 17 Additional Aspects of Aqueous Equilibria (Part A)
Chapter 17 Additional Aspects of Aqueous Equilibria (Part A) Often, there are many equilibria going on in an aqueous solution. So, we must determine the dominant equilibrium (i.e. the equilibrium reaction
More informationIntroduction to biochemical practicals. Vladimíra Kvasnicová
Introduction to biochemical practicals Vladimíra Kvasnicová arrangement of practicals laboratory safety regulations laboratory equipment dealing with automatic pipette instructions: http://vyuka.lf3.cuni.cz/
More informationSo, What Does it Indicate?
So, What Does it Indicate? Introduction Phenolphthalein is a common indicator you may have used in a previous science course, such as Chemistry 184. In solutions with a ph of less then 8.3, this compound
More informationCHM 130 Acid-Base Titration Molarity of Acetic Acid in Vinegar
CHM 130 Acid-Base Titration Molarity of Acetic Acid in Vinegar INTRODUCTION One of the most important techniques for chemical analysis is titration to an equivalence point. To illustrate this procedure,
More information7/30/2015. by ph Titration TEST EXERCISE (105 points) Quiz 2 Tuesday August 4. SUSB013 Colorimetric Determination Aspirin
// Quiz Tuesday August SUSB Colorimetric Determination Aspirin SUSB Colorimetric Iron in Multivitamins SUSB Complexometric Titration Calcium in Antacid? TITRATION OF SA AND ASA WITH NaOH vs VOLUME OF NaOH
More informationSupporting information. Proton-Coupled Electron Transport in Anthraquinone-based Zirconium Metal-Organic Frameworks
Supporting information Proton-Coupled Electron Transport in Anthraquinone-based Zirconium Metal-Organic Frameworks Paula J. Celis-Salazar, Charity C. Epley, Spencer R. Ahrenholtz, William A. Maza, Pavel
More informationVDL ENDOTOXIN ASSAY: ASSAY FOR LIMULUS AMEBOCYTE LYSATE
1. Purpose 1.1. The purpose of this protocol is test purified viral vectors for endotoxin contamination. 1.2. This procedure is routinely performed in the Vector Development Laboratory (VDL) following
More informationComparison of US Pharmacopeia Simulated Intestinal Fluid TS (without pancreatin)
dx.doi.org/10.14227/dt110204p6 Comparison of US Pharmacopeia Simulated Intestinal Fluid TS (without pancreatin) and Phosphate Standard Buffer ph 6.8, TS of the International Pharmacopoeia with Respect
More informationQuestions #4-5 The following two questions refer to the following system: A 1.0L solution contains 0.25M HF and 0.60M NaF (Ka for HF = 7.2 x 10-4 ).
Multiple Choice 1) A solution contains 0.250 M HA (K a = 1.0 x 10-6 ) and 0.45 M NaA. What is the ph after 0.10 mole of HCl is added to 1.00L of this solution? a. 3.17 b. 3.23 c. 6.00 d. 10.77 e. 10.83
More informationDetermination of the Identity of an Unknown Weak Acid
Determination of the Identity of an Unknown Weak Acid Adapted from R. C. Kerber et. al http://www.sinc.sunysb.edu/class/orgolab/che199_susb014.pdf; W.F. Kinard et.al http://www.cofc.edu/~kinard/221lchem/2002chem221labschedule.htm;
More informationMEASUREMENT OF ph: INTRODUCTION TO BUFFER AND BASICS OF ph METER
Theory module: 04(MCQ) METER 1. To prepare 1000 ml of 0.1M phosphate buffer of ph 7.5 (pka of NaH2PO4= 7.2). how many ml of each buffer components will be required? Molecular weight of Na2HPO4 and NaH2PO4
More informationRAPID KJELDAHL BENCHNOTES
RAPID KJELDAHL BENCHNOTES Methodology for the Determination of Alcohol in a Mixture by Direct Distillation with the RapidStill II Principle: This method covers the determination of percent alcohol in distilled
More informationPreparation of different buffer solutions
Preparation of different buffer solutions 1 - Buffers: - All biochemical reactions occur under strict conditions of the concentration of hydrogen ion. - Biological life cannot withstand large changes in
More informationGeneral Practical Chemistry EXPERIMENTS REOPRTS 101 Chem & 104 Chem
King Saud University Faculty of Science Chemistry Department General Practical Chemistry EXPERIMENTS REOPRTS 101 Chem & 104 Chem Text Book: Practical General Chemistry By Dr. Ahmad Al-Owais & Dr. Abdulaziz
More informationSynthesis and Analysis of a Coordination Compound
Synthesis and Analysis of a Coordination Compound In addition to forming salts with anions, transition metal cations can also associate with neutral molecules (and ions) through a process called ligation.
More informationof nm throughout the experimental work.
Difference Spectrophotometric Methods for Pioglitazone Hydrochloride and Metformin Hydrochloride K.Sujana, K.Abbulu, O.Bala Souri, B.Archana, M.Sindu, G.Swathi Rani Department of Pharmaceutical Analysis,
More informationStrikingly different miscibility of n-octanol in highly-confined and quasi-confined water
Electronic Supplementary Material (ESI) for ChemComm. This journal is The Royal Society of Chemistry 2015 Strikingly different miscibility of n-octanol in highly-confined and quasi-confined water Aparajita
More informationTotal, active and effective alkali
Accepted April 1985 White and green liquors Total, actie and effectie alkali Potentiometric titration 0 Introduction This SCAN-test Method has been deeloped for use in laboratories employing electrometric
More informationA near-infrared colorimetric fluorescent chemodosimeter for the detection of glutathione in living cells
Electronic Supplementary Material (ESI) for Chemical Communications Electronic Supplementary Information (ESI) A near-infrared colorimetric fluorescent chemodosimeter for the detection of glutathione in
More information5/10/2017. Chapter 10. Acids, Bases, and Salts
Chapter 10. Acids, Bases, and Salts Introduction to Inorganic Chemistry Instructor Dr. Upali Siriwardane (Ph.D. Ohio State) E-mail: upali@latech.edu Office: 311 Carson Taylor Hall ; Phone: 318-257-4941;
More informationAP Chemistry: Acid-Base Chemistry Practice Problems
Name AP Chemistry: Acid-Base Chemistry Practice Problems Date Due Directions: Write your answers to the following questions in the space provided. For problem solving, show all of your work. Make sure
More informationLABORATORIUM Z CHEMII FIZYCZNEJ POTENTIOMETRIC MEASUREMENTS OF PH POLITECHNIKA ŚLĄSKA WYDZIAŁ CHEMICZNY. Agata Blacha-Grzechnik.
POLITCHNIKA ŚLĄSKA WYDZIAŁ CHMICZNY KATDRA IZYKOCHMII I TCHNOLOGII POLIMRÓW POTNTIOMTRIC MASURMNTS O PH Prowadzący: Miejsce ćwiczenia: Agata BlachaGrzechnik Katedra izykochemii i Technologii Polimerów,
More informationNow, the excess strong base will react: HA + OH - A - + H 2 O Start mol End mol
Chemistry Spring 016 Exam 3: Chapters 8-10 Name 80 Points Complete problem 1 and four of problems -6. CLEARLY mark the problem you do not want graded. You must show your work to receive credit for problems
More informationAcid Base Equilibria
Acid Base Equilibria Acid Ionization, also known as acid dissociation, is the process in where an acid reacts with water to produce a hydrogen ion and the conjugate base ion. HC 2 H 3 O 2(aq) H + (aq)
More informationSo, What Does it Indicate?
So, What Does it Indicate? Introduction Phenolphthalein is a common indicator you may have used in a previous science course, such as Chemistry 130 or Chemistry 170. In solutions with a ph of less then
More informationChapter 4 Materials and Methods
Chapter 4 Materials and Methods 4.1 pka Determination 4.1.1 Overview This experiment determines values for the three pkas and four absorptivity factors of fluorescein by fitting the ph/absorbance profile
More informationChemistry 1B Experiment 17 89
Chemistry 1B Experiment 17 89 17 Thermodynamics of Borax Solubility Introduction In this experiment, you will determine the values of H and S for the reaction which occurs when borax (sodium tetraborate
More informationChem 460 Laboratory Fall 2008 Experiment 3: Investigating Fumarase: ph Profile, Stereospecificity and Thermodynamics of Reaction
1 Chem 460 Laboratory Fall 2008 Experiment 3: Investigating Fumarase: ph Profile, Stereospecificity and Thermodynamics of Reaction Before Lab Week 1 -- ph Profile for Fumarase Read Box 11-1 (page 323)
More informationDETERMINATION OF DRUG RELEASE DURING DISSOLUTION OF NICORANDIL IN TABLET DOSAGE FORM BY USING REVERSE PHASE HIGH PERFORMANCE LIQUID CHROMATOGRAPHY
CHAPTER 9 DETERMINATION OF DRUG RELEASE DURING DISSOLUTION OF NICORANDIL IN TABLET DOSAGE FORM BY USING REVERSE PHASE HIGH PERFORMANCE LIQUID CHROMATOGRAPHY CHAPTER 9 Determination of drug release during
More informationPartner: Judy 29 March Analysis of a Commercial Bleach
Partner: Judy 29 March 2012 Analysis of a Commercial Bleach Purpose: The purpose of this lab is to determine the amount of sodium hypochlorite (NaClO) in commercial bleach. This can be done by forming
More informationLecture 12. Acid/base reactions. Equilibria in aqueous solutions.
Lecture 12 Acid/base reactions. Equilibria in aqueous solutions. Titrations Kotz 7 th ed. Section 18.3, pp.821-832. In a titration a solution of accurately known concentration is added gradually added
More informationAnnex 2 Formaldehyde
Annex 2 Formaldehyde The 2 methods are analytical procedures for the determination of formaldehyde CH2O, PM/Ref. No 17260, and hexamethylenetetramine (HMTA) C6H12N4, PM/Ref. No 18670, in food simulants
More informationElectronic Supplementary Information for. A Redox-Nucleophilic Dual-Reactable Probe for Highly Selective
Electronic Supplementary Information for A Redox-Nucleophilic Dual-Reactable Probe for Highly Selective and Sensitive Detection of H 2 S: Synthesis, Spectra and Bioimaging Changyu Zhang, 1 Runyu Wang,
More informationBuffer solutions Strong acids and bases dissociate completely and change the ph of a solution drastically. Buffers are solutions that resist changes i
18.3 ph Curves Buffer solutions Strong acids and bases dissociate completely and change the ph of a solution drastically. Buffers are solutions that resist changes in ph even when acids and bases are added
More informationRecommended Procedures for Labeling. Labeling Proteins with Amine-Reactive ATTO-Labels (NHS-Esters) Introduction
Recommended Procedures for Labeling Introduction ATTO-TEC offers a large variety of high-quality dyes for labeling amino and thiol groups. ATTO reactive dyes cover the spectral region from 350 nm in the
More informationDetermination of equivalence point using ph titration of Potassium Hydrogen Phalate and 0.1 N Sodium Hydroxide with phenolphthalein indicator
General Chemistry II Spring Semester Bellevue College Department of Chemistry Determination of equivalence point using ph titration of Potassium Hydrogen Phalate and 0.1 N Sodium Hydroxide with phenolphthalein
More informationA dual-model and on off fluorescent Al 3+ /Cu 2+ - chemosensor and the detection of F /Al 3+ with in situ prepared Al 3+ /Cu 2+ complex
Supporting Information (SI) A dual-model and on off fluorescent Al 3+ /Cu 2+ - chemosensor and the detection of F /Al 3+ with in situ prepared Al 3+ /Cu 2+ complex Xiaoya Li, Mingming Yu, Faliu Yang, Xingjiang
More informationLAB 8: DETERMINATION OF ACETIC ACID CONTENT IN VINEGAR
LAB 8: DETERMINATIN F AETI AID NTENT IN VINEGAR Lab format: This lab is designed for delivery using the Remote Web-based Science Laboratory (RWSL) or a lab kit. INTRDUTIN In an acid-base titration, the
More informationUltra-Sensitive ph Control of Supramolecular Polymers and Hydrogels: pk a Matching of Biomimetic Monomers
Electronic Supplementary Material (ESI) for Chemical Science. This journal is The Royal Society of Chemistry 2014 Supplementary Information for Ultra-Sensitive ph Control of Supramolecular Polymers and
More informationAssay procedure for. PeliKine compact TM ELISA kit (288 tests) Research Use Only. Sanquin Reagents
Assay procedure for PeliKine compact TM ELISA kit (288 tests) Research Use Only Sanquin Reagents Plesmanlaan 125 1066 CX Amsterdam The Netherlands reagents@sanquin.nl www.sanquinreagents.com For The Netherlands
More informationChapter 4 Reactions in Aqueous Solutions. Copyright McGraw-Hill
Chapter 4 Reactions in Aqueous Solutions Copyright McGraw-Hill 2009 1 4.1 General Properties of Aqueous Solutions Solution - a homogeneous mixture Solute: the component that is dissolved Solvent: the component
More informationH + [ ] [ ] H + NH 3 NH 4. = poh + log HB +
Titration Lab: Determination of a pk a for an Acid and for a Base Theory A Brønsted-Lowry acid is a substance that ionizes in solution (usually aqueous, but it doesn t have to be, ammonia is often used
More informationAcid-Base Equilibria. And the beat goes on Buffer solutions Titrations
Acid-Base Equilibria And the beat goes on Buffer solutions Titrations 1 Common Ion Effect The shift in equilibrium due to addition of a compound having an ion in common with the dissolved substance. 2
More information