This document introduces zeta potential and its importance in optimizing formulations of suspensions and emulsions. It discusses how zeta potential can be used to predict stability and reduce trial formulations. It then covers colloid science fundamentals and theories like DVLO theory that relate zeta potential to colloidal stability. Specifically, it states that zeta potential indicates the stability of the system, with values above +30 mV or below -30 mV generally indicating stability.
The document discusses various concepts related to compaction, compression, and consolidation in pharmaceutical tableting including definitions, mechanisms, factors affecting the processes, and instrumentation used to measure forces. It describes the key steps in compression as transitional repacking, deformation, fragmentation, bonding, deformation of the solid, decompression, and ejection. It also discusses factors that influence consolidation and methods for measuring the distribution of forces within powder masses undergoing compression.
The document discusses dissolution as a tool in pharmaceutics. It defines dissolution as the process where a solid substance solubilizes in a solvent, transferring from the solid surface to the liquid phase. This is the rate-determining step for poorly soluble drugs. The document discusses three main mechanisms of dissolution - the diffusion layer model, Danckwert's model, and the interfacial barrier model. It also covers factors influencing dissolution such as drug properties, apparatus factors, and dissolution media properties. Finally, it provides details on three common dissolution apparatus - the basket, paddle, and reciprocating cylinder methods.
This document discusses the concept of zeta potential, which is the electric potential at the boundary between the particle surface and the surrounding liquid. It defines zeta potential and explains factors that affect it such as pH and ionic strength. The document also describes how zeta potential is measured using electrokinetic phenomena like electrophoresis. Finally, it discusses applications of zeta potential measurement and DLVO theory of colloid stability.
This document discusses rheology, the science of deformation of matter under stress. It defines tensile and shearing stresses and explains reversible and irreversible deformations. Viscosity is introduced as the resistance of fluids to flow, with Newtonian fluids obeying the law of proportionality between stress and shear rate. Non-Newtonian fluids are divided into time-dependent categories like thixotropy and time-independent types including plastic, pseudoplastic and dilatant flows. Specific examples and rheograms are provided to illustrate different fluid behaviors.
“It is a process by which a drug leaves a drug product
& is subjected to ADME & eventually becoming
available for pharmacological action.”
It involves the study of drug release rate, dissolution
/diffusion/erosion studies and the study of factors
affecting release rate of the drug.
A contact angle goniometer measures the contact angle of a liquid on a solid surface and can
obtain surface energy of a solid. This instrument is used in all the major industries; especially
where research is done in coming up with newer materials. Low values of contact angle indicate
greater wettability and higher values mean that the solid doesn’t attract the liquid as much. This
instrument already exists but with my design it costs over ten times less, which will make it more
accessible to school labs and small-scale industries.
Filtration is a process that separates solids from liquids or gases using a porous medium. As the suspension passes through the medium, solids are retained while the liquid or gas passes through. Key factors that affect the filtration rate include properties of the fluid and solids, concentration of solids, filter area, and resistance of the filter medium and cake buildup. The two main types of liquid filtration are cake filtration, where particles build up on the surface of the medium, and deep bed filtration, where particles penetrate the medium pores to remove fine particles from dilute suspensions. Proper filter selection depends on required filtrate quality, throughput, and operating costs. Common industrial filters include bag, plate and frame, pressure leaf,
Dissolution testing conventional and controlled release productsMd Fiaz
Dissolution testing is important for quality control and predicting in vivo performance of drug products. It quantifies the rate and amount of drug released from solid oral dosage forms under standardized conditions. Key factors in designing a dissolution test include the apparatus, media, and acceptance criteria. The most common apparatuses are USP Type I (baskets), Type II (paddles), and Type IV (flow-through cells). Media include water, buffers, and simulated gastric/intestinal fluids. Acceptance criteria ensure a minimum percentage of drug dissolves within a specified time for quality batches. Dissolution testing is critical for developing and evaluating conventional and controlled-release drug products.
The document discusses various concepts related to compaction, compression, and consolidation in pharmaceutical tableting including definitions, mechanisms, factors affecting the processes, and instrumentation used to measure forces. It describes the key steps in compression as transitional repacking, deformation, fragmentation, bonding, deformation of the solid, decompression, and ejection. It also discusses factors that influence consolidation and methods for measuring the distribution of forces within powder masses undergoing compression.
The document discusses dissolution as a tool in pharmaceutics. It defines dissolution as the process where a solid substance solubilizes in a solvent, transferring from the solid surface to the liquid phase. This is the rate-determining step for poorly soluble drugs. The document discusses three main mechanisms of dissolution - the diffusion layer model, Danckwert's model, and the interfacial barrier model. It also covers factors influencing dissolution such as drug properties, apparatus factors, and dissolution media properties. Finally, it provides details on three common dissolution apparatus - the basket, paddle, and reciprocating cylinder methods.
This document discusses the concept of zeta potential, which is the electric potential at the boundary between the particle surface and the surrounding liquid. It defines zeta potential and explains factors that affect it such as pH and ionic strength. The document also describes how zeta potential is measured using electrokinetic phenomena like electrophoresis. Finally, it discusses applications of zeta potential measurement and DLVO theory of colloid stability.
This document discusses rheology, the science of deformation of matter under stress. It defines tensile and shearing stresses and explains reversible and irreversible deformations. Viscosity is introduced as the resistance of fluids to flow, with Newtonian fluids obeying the law of proportionality between stress and shear rate. Non-Newtonian fluids are divided into time-dependent categories like thixotropy and time-independent types including plastic, pseudoplastic and dilatant flows. Specific examples and rheograms are provided to illustrate different fluid behaviors.
“It is a process by which a drug leaves a drug product
& is subjected to ADME & eventually becoming
available for pharmacological action.”
It involves the study of drug release rate, dissolution
/diffusion/erosion studies and the study of factors
affecting release rate of the drug.
A contact angle goniometer measures the contact angle of a liquid on a solid surface and can
obtain surface energy of a solid. This instrument is used in all the major industries; especially
where research is done in coming up with newer materials. Low values of contact angle indicate
greater wettability and higher values mean that the solid doesn’t attract the liquid as much. This
instrument already exists but with my design it costs over ten times less, which will make it more
accessible to school labs and small-scale industries.
Filtration is a process that separates solids from liquids or gases using a porous medium. As the suspension passes through the medium, solids are retained while the liquid or gas passes through. Key factors that affect the filtration rate include properties of the fluid and solids, concentration of solids, filter area, and resistance of the filter medium and cake buildup. The two main types of liquid filtration are cake filtration, where particles build up on the surface of the medium, and deep bed filtration, where particles penetrate the medium pores to remove fine particles from dilute suspensions. Proper filter selection depends on required filtrate quality, throughput, and operating costs. Common industrial filters include bag, plate and frame, pressure leaf,
Dissolution testing conventional and controlled release productsMd Fiaz
Dissolution testing is important for quality control and predicting in vivo performance of drug products. It quantifies the rate and amount of drug released from solid oral dosage forms under standardized conditions. Key factors in designing a dissolution test include the apparatus, media, and acceptance criteria. The most common apparatuses are USP Type I (baskets), Type II (paddles), and Type IV (flow-through cells). Media include water, buffers, and simulated gastric/intestinal fluids. Acceptance criteria ensure a minimum percentage of drug dissolves within a specified time for quality batches. Dissolution testing is critical for developing and evaluating conventional and controlled-release drug products.
A presentation on Diamond-like Carbon Thin Film with Controlled Zeta Potential for Medical Application made by Deepak Rajput. It was presented as a course requirement at the University of Tennessee Space Institute in Fall 2008.
Large scale manufacturing processes &; equipments for Tablets Rohan Jagdale
This presentation gives general ideas about tablet formulation on large scale and gives information about modern Pharma equipments for Tablets manufacturing.
1) Tablet compression involves the application of force to reduce the volume of powder materials through three main processes: compression, compaction, and consolidation. Compression removes air, compaction rearranges particles, and consolidation increases strength through bonding.
2) Key forces involved in compression include inter-particulate and die wall friction, which can be reduced by adding glidants and lubricants, respectively. Distribution forces transmit pressure from the punches to the powder bed and die wall.
3) Compaction profiles examine the relationship between axial and radial pressure. They provide information on elastic versus plastic deformation and ejection forces.
1. Dissolution is the process by which a solid substance dissolves in a solvent to form a solution. The rate of dissolution depends on factors like temperature, solvent composition, and the liquid/solid interface area.
2. There are several theories that describe the drug dissolution process, including the diffusion layer model, penetration or surface renewal theory, and interfacial barrier model. The most common model is the diffusion layer model, which involves the formation of a saturated film at the solid/liquid interface and diffusion of the drug through this layer.
3. Key factors that affect drug dissolution include the solubility and permeability of the drug substance, the pH and volume of the dissolution medium, and the design of
Physics of tablet compression, mechanism of tablet
formation, bonding in tablets, the effect of compressional force on tablet properties, effect
of lubricants on tablet compression, binding, instrumented tablet machines and tooling,
problems associated with large scale manufacturing of tablets.
This presentation discusses zeta potential and its determination. Zeta potential is defined as the potential difference between the dispersion medium and stationary layer of fluid attached to dispersed particles. There are several methods to determine zeta potential including electrophoresis, streaming potential, and electro-osmosis. Zeta potential is a key indicator of stability in colloidal dispersions - higher zeta potential leads to more electrostatic repulsion and stability against aggregation. Zeta potential has applications in areas like water purification, minerals processing, emulsions, and pharmaceuticals.
The document discusses key topics in powder compression:
1. Compression properties like compressibility and compactibility are important for forming tablets.
2. Axial and radial forces are exerted during compression and must be withstood for decompression.
3. The compression process involves stages like particle rearrangement, deformation, fragmentation, and bonding which increase density and form strong tablets.
1. Filtration is used to separate solids from liquids using a porous medium, and is affected by factors like thickness of the filter medium, viscosity of the fluid, pressure difference, and area.
2. Darcy's equation quantifies the factors that affect filtration rate. Methods to increase rate include increasing pressure/area or decreasing thickness/viscosity.
3. Filter aids like diatomaceous earth are added to improve flow rate and decrease cake thickness. They are commonly used in pharmaceutical, chemical and food industries.
4. Key filtration methods are gravity, vacuum, centrifugal and pressure filtration. Filter presses use pressure and plates to filter large volumes.
Introduction,Drug- Excipient Compatibility Experimental Design ,Excipient role in drug destabilization,DRUG EXCIPIENT COMPATIBILTY IN PARENTERAL PRODUCTS.This topic are described.
Overview of Zeta Potential Concept, Measurement Use, and ApplicationsHORIBA Particle
This document provides an overview of zeta potential, which is a measure of the surface charge of particles in suspension. It discusses how particle surfaces acquire charges in water through various mechanisms and how factors like pH, electrolyte concentration, and surface modifications can affect zeta potential. The document also explains how zeta potential relates to particle stability and interactions, with higher zeta potential generally leading to better dispersion stability. Measurement of zeta potential can provide useful insights into suspension behavior and material performance.
1) Solubility is the maximum amount of a substance that dissolves in a solvent to form a saturated solution at a given temperature and pressure.
2) Solubility is ideally measured at 4°C and 37°C to ensure physical stability and support biopharmaceutical evaluation. Solubility below 1 mg/ml indicates poor absorption and need for preformulation studies.
3) Preformulation solubility studies focus on the drug solvent system and include determining properties like intrinsic solubility, pH solubility profiles, effects of surfactants, and temperature dependence to understand a drug's solubility and dissolution behavior.
WHAT IS LIQUID LIQUID EXTRACTION?
STEPS OF LIQUID LIQUID EXTRACTION
SCHEMATIC DIAGRAM OF EXTRACTION PROCESS
WHERE WE CAN USE LIQUID LIQUID EXTRACTION
TERNARY SYSTEM
LIQUID LIQUID EQUILIBRIA
EXPERIMENTAL DETERMINATION OF LLE DATA
GRAPHICAL REPRESENTATION OF LLE DATA
EQUILATERAL TRIANGULAR DIAGRAM
EFFECTS OF TEMPERATURE ON ETD
RECTANGULAR TRIANGULAR DIAGRAM
CRITERIA FOR SOLVENT SELECTION
The document discusses the Van Deemter equation, which relates the height equivalent to a theoretical plate (HETP) in gas chromatography to experimental parameters like particle diameter, diffusion coefficients, and flow rate. It explains that HETP is affected by eddy diffusion, longitudinal diffusion, and mass transfer between phases. The Van Deemter equation can be used to optimize chromatographic performance by identifying conditions that minimize band broadening like adjusting flow rates and using smaller stationary phase particles.
Chromatography is a technique used to separate mixtures by distributing components between two phases - a stationary phase and a mobile phase. Mikhail Tswett discovered chromatography in 1906 when separating plant pigments. There are various types of chromatography classified by mobile phase (liquid, gas), stationary phase material (thin layer, paper, column), or separation mechanism (adsorption, partition, ion exchange, size exclusion, affinity). Chromatography has many applications in science and industry, including purification of antibiotics, vaccines, enzymes, and other biomolecules.
Dynamic light scattering measures the fluctuation changes in the intensity of scattered light to determine particle size and properties. It works by measuring the rate at which the intensity of scattered light fluctuates due to Brownian motion of particles. Larger particles diffuse more slowly than smaller particles, so intensity fluctuations are slower for large particles. The correlation function contains information about particle diffusion, with steeper curves indicating more monodisperse samples and more extended decay indicating greater polydispersity. Dynamic light scattering can determine particle size distribution, hydrodynamic radius, and diffusion coefficient.
This document discusses co-processed excipients. Excipients are added to active pharmaceutical ingredients to facilitate drug delivery and manufacturing. Co-processing involves combining two or more excipients through solvent dissolution and drying to create new excipients with improved properties. Co-processed excipients can improve flow, compressibility, reduce lubricant sensitivity and provide multiple functionalities from a single excipient. They are evaluated based on parameters like particle size distribution, Carr's index and Hausner ratio. Co-processing offers benefits like improved formulation properties and palatability.
This presentation contains all the topics related to column chromatography. That includes introduction, principle,apparatus, experimental aspects of column chromatography, application of column chromatography, advantage and disadvantage of column chromatography with reference.
This document discusses mechanisms of drug dissolution from solid oral dosage forms. It begins with an introduction on the importance of dissolution testing. It then covers several theories of dissolution mechanisms including diffusion layer theory, reaction limited models, and the Carstensen scheme. Mathematical models of drug release kinetics are also discussed, including zero-order, first-order, Higuchi, Korsmeyer-Peppas, and Hixson-Crowell models. The document provides details on each model and their applications and limitations in describing drug dissolution and release profiles from different drug delivery systems.
This document provides an overview of chromatography techniques. It defines chromatography as a physical separation method that distributes components between two phases, one stationary and one mobile. It then classifies chromatography based on the stationary and mobile phases used as well as the instruments involved. Several chromatography techniques are described in detail, including thin layer chromatography. The principles, components, preparation, and considerations for thin layer chromatography are explained.
A aluna Justine do 1o ano E marcou o ônibus como o meio de transporte que mais utiliza. Ela listou carro e moto como meios terrestres, avião e foguete como meios aéreos e navio e submarino como meios aquáticos. O documento solicita informações sobre os principais meios de transporte.
Abs 497 week 5 discussion question macro social systemselclipymov1981
This document outlines discussion questions and assignments for a course on macro social systems theories and applied behavioral science. It includes prompts to discuss functionalism, conflict theory, and interactionism perspectives on crime and delinquency. Other assignments involve describing the field of applied behavioral science, professional values and ethics, empowerment theory, theories on how groups function, evidence-based practice, and power in organizations. Students are to write on these topics, citing scholarly references and responding to classmates. The document also provides instructions for outlining a final paper on a topic related to applied behavioral science.
A presentation on Diamond-like Carbon Thin Film with Controlled Zeta Potential for Medical Application made by Deepak Rajput. It was presented as a course requirement at the University of Tennessee Space Institute in Fall 2008.
Large scale manufacturing processes &; equipments for Tablets Rohan Jagdale
This presentation gives general ideas about tablet formulation on large scale and gives information about modern Pharma equipments for Tablets manufacturing.
1) Tablet compression involves the application of force to reduce the volume of powder materials through three main processes: compression, compaction, and consolidation. Compression removes air, compaction rearranges particles, and consolidation increases strength through bonding.
2) Key forces involved in compression include inter-particulate and die wall friction, which can be reduced by adding glidants and lubricants, respectively. Distribution forces transmit pressure from the punches to the powder bed and die wall.
3) Compaction profiles examine the relationship between axial and radial pressure. They provide information on elastic versus plastic deformation and ejection forces.
1. Dissolution is the process by which a solid substance dissolves in a solvent to form a solution. The rate of dissolution depends on factors like temperature, solvent composition, and the liquid/solid interface area.
2. There are several theories that describe the drug dissolution process, including the diffusion layer model, penetration or surface renewal theory, and interfacial barrier model. The most common model is the diffusion layer model, which involves the formation of a saturated film at the solid/liquid interface and diffusion of the drug through this layer.
3. Key factors that affect drug dissolution include the solubility and permeability of the drug substance, the pH and volume of the dissolution medium, and the design of
Physics of tablet compression, mechanism of tablet
formation, bonding in tablets, the effect of compressional force on tablet properties, effect
of lubricants on tablet compression, binding, instrumented tablet machines and tooling,
problems associated with large scale manufacturing of tablets.
This presentation discusses zeta potential and its determination. Zeta potential is defined as the potential difference between the dispersion medium and stationary layer of fluid attached to dispersed particles. There are several methods to determine zeta potential including electrophoresis, streaming potential, and electro-osmosis. Zeta potential is a key indicator of stability in colloidal dispersions - higher zeta potential leads to more electrostatic repulsion and stability against aggregation. Zeta potential has applications in areas like water purification, minerals processing, emulsions, and pharmaceuticals.
The document discusses key topics in powder compression:
1. Compression properties like compressibility and compactibility are important for forming tablets.
2. Axial and radial forces are exerted during compression and must be withstood for decompression.
3. The compression process involves stages like particle rearrangement, deformation, fragmentation, and bonding which increase density and form strong tablets.
1. Filtration is used to separate solids from liquids using a porous medium, and is affected by factors like thickness of the filter medium, viscosity of the fluid, pressure difference, and area.
2. Darcy's equation quantifies the factors that affect filtration rate. Methods to increase rate include increasing pressure/area or decreasing thickness/viscosity.
3. Filter aids like diatomaceous earth are added to improve flow rate and decrease cake thickness. They are commonly used in pharmaceutical, chemical and food industries.
4. Key filtration methods are gravity, vacuum, centrifugal and pressure filtration. Filter presses use pressure and plates to filter large volumes.
Introduction,Drug- Excipient Compatibility Experimental Design ,Excipient role in drug destabilization,DRUG EXCIPIENT COMPATIBILTY IN PARENTERAL PRODUCTS.This topic are described.
Overview of Zeta Potential Concept, Measurement Use, and ApplicationsHORIBA Particle
This document provides an overview of zeta potential, which is a measure of the surface charge of particles in suspension. It discusses how particle surfaces acquire charges in water through various mechanisms and how factors like pH, electrolyte concentration, and surface modifications can affect zeta potential. The document also explains how zeta potential relates to particle stability and interactions, with higher zeta potential generally leading to better dispersion stability. Measurement of zeta potential can provide useful insights into suspension behavior and material performance.
1) Solubility is the maximum amount of a substance that dissolves in a solvent to form a saturated solution at a given temperature and pressure.
2) Solubility is ideally measured at 4°C and 37°C to ensure physical stability and support biopharmaceutical evaluation. Solubility below 1 mg/ml indicates poor absorption and need for preformulation studies.
3) Preformulation solubility studies focus on the drug solvent system and include determining properties like intrinsic solubility, pH solubility profiles, effects of surfactants, and temperature dependence to understand a drug's solubility and dissolution behavior.
WHAT IS LIQUID LIQUID EXTRACTION?
STEPS OF LIQUID LIQUID EXTRACTION
SCHEMATIC DIAGRAM OF EXTRACTION PROCESS
WHERE WE CAN USE LIQUID LIQUID EXTRACTION
TERNARY SYSTEM
LIQUID LIQUID EQUILIBRIA
EXPERIMENTAL DETERMINATION OF LLE DATA
GRAPHICAL REPRESENTATION OF LLE DATA
EQUILATERAL TRIANGULAR DIAGRAM
EFFECTS OF TEMPERATURE ON ETD
RECTANGULAR TRIANGULAR DIAGRAM
CRITERIA FOR SOLVENT SELECTION
The document discusses the Van Deemter equation, which relates the height equivalent to a theoretical plate (HETP) in gas chromatography to experimental parameters like particle diameter, diffusion coefficients, and flow rate. It explains that HETP is affected by eddy diffusion, longitudinal diffusion, and mass transfer between phases. The Van Deemter equation can be used to optimize chromatographic performance by identifying conditions that minimize band broadening like adjusting flow rates and using smaller stationary phase particles.
Chromatography is a technique used to separate mixtures by distributing components between two phases - a stationary phase and a mobile phase. Mikhail Tswett discovered chromatography in 1906 when separating plant pigments. There are various types of chromatography classified by mobile phase (liquid, gas), stationary phase material (thin layer, paper, column), or separation mechanism (adsorption, partition, ion exchange, size exclusion, affinity). Chromatography has many applications in science and industry, including purification of antibiotics, vaccines, enzymes, and other biomolecules.
Dynamic light scattering measures the fluctuation changes in the intensity of scattered light to determine particle size and properties. It works by measuring the rate at which the intensity of scattered light fluctuates due to Brownian motion of particles. Larger particles diffuse more slowly than smaller particles, so intensity fluctuations are slower for large particles. The correlation function contains information about particle diffusion, with steeper curves indicating more monodisperse samples and more extended decay indicating greater polydispersity. Dynamic light scattering can determine particle size distribution, hydrodynamic radius, and diffusion coefficient.
This document discusses co-processed excipients. Excipients are added to active pharmaceutical ingredients to facilitate drug delivery and manufacturing. Co-processing involves combining two or more excipients through solvent dissolution and drying to create new excipients with improved properties. Co-processed excipients can improve flow, compressibility, reduce lubricant sensitivity and provide multiple functionalities from a single excipient. They are evaluated based on parameters like particle size distribution, Carr's index and Hausner ratio. Co-processing offers benefits like improved formulation properties and palatability.
This presentation contains all the topics related to column chromatography. That includes introduction, principle,apparatus, experimental aspects of column chromatography, application of column chromatography, advantage and disadvantage of column chromatography with reference.
This document discusses mechanisms of drug dissolution from solid oral dosage forms. It begins with an introduction on the importance of dissolution testing. It then covers several theories of dissolution mechanisms including diffusion layer theory, reaction limited models, and the Carstensen scheme. Mathematical models of drug release kinetics are also discussed, including zero-order, first-order, Higuchi, Korsmeyer-Peppas, and Hixson-Crowell models. The document provides details on each model and their applications and limitations in describing drug dissolution and release profiles from different drug delivery systems.
This document provides an overview of chromatography techniques. It defines chromatography as a physical separation method that distributes components between two phases, one stationary and one mobile. It then classifies chromatography based on the stationary and mobile phases used as well as the instruments involved. Several chromatography techniques are described in detail, including thin layer chromatography. The principles, components, preparation, and considerations for thin layer chromatography are explained.
A aluna Justine do 1o ano E marcou o ônibus como o meio de transporte que mais utiliza. Ela listou carro e moto como meios terrestres, avião e foguete como meios aéreos e navio e submarino como meios aquáticos. O documento solicita informações sobre os principais meios de transporte.
Abs 497 week 5 discussion question macro social systemselclipymov1981
This document outlines discussion questions and assignments for a course on macro social systems theories and applied behavioral science. It includes prompts to discuss functionalism, conflict theory, and interactionism perspectives on crime and delinquency. Other assignments involve describing the field of applied behavioral science, professional values and ethics, empowerment theory, theories on how groups function, evidence-based practice, and power in organizations. Students are to write on these topics, citing scholarly references and responding to classmates. The document also provides instructions for outlining a final paper on a topic related to applied behavioral science.
The document describes the migration patterns of the author's Mexican and German family sides. The Mexican family originally came from Zacatecas, Mexico and settled in La Puente, California before splitting up to locations including Orange County, Chino, Ontario, and Pomona. The German family came from Germany and settled in Pennsylvania before relocating to Alhambra, California, with half the family then moving to Idaho and the other half remaining in California, where the author now lives in Ontario.
This document discusses production and processing of unripe bananas into value-added products to reduce post-harvest losses. It describes how unripe bananas can be processed into chips, flour, and jam. The process for each product is outlined, along with their health benefits and uses. Challenges in production such as maintaining quality and shelf life are discussed along with recommendations to address them like careful handling, proper drying and storage. The document concludes that banana processing can provide opportunities for rural entrepreneurs given growing demand for healthy banana products.
The document discusses how successful global companies identify opportunities in foreign markets. It outlines a 5-step process: 1) identify relevant criteria, 2) assign weights to criteria, 3) narrow down alternatives, 4) systematically compare alternatives, and 5) evaluate ability to exploit opportunities. The document provides a table comparing economic and demographic data of several countries and regions to illustrate applying the process and identifying the most attractive market opportunities.
O documento é um questionário sobre meios de transporte preenchido por um aluno chamado nicoly do 1o ano. Ele marcou o carro como o meio de transporte que mais utiliza e listou carro e ônibus como transportes terrestres, avião e balão como transportes aéreos e barco e navio como transportes aquáticos.
The trailer begins by establishing the main character John McGill as intelligent and from an upper-class background, but he is punished in school for his intelligence. He is warned to not follow the path of his older brother, implying his brother is violent. John joins a gang and becomes increasingly violent, throwing lit fireworks into a house. The trailer ends with two gangs charging at each other on a bridge, highlighting the intense violence, and John is shown dead under a statue of Christ with a knife by him.
The NET position at AIESEC in Georgia is responsible for raising partnerships through sales campaigns with companies and NGOs for programs like the Global Management Program and Incoming Global Internship Program. The position is open for 6 months and will be evaluated after 3 months, with the potential for restructuring or reopening if performance is low. Members from all AIESEC Georgia departments can apply. Filling this role would help AIESEC Georgia meet their midterm goal for 2015 and become the preferred partner by the end of next year.
Zeta potential is a scientific term for electrokinetic potential (Zeta) in colloidal dispersions.
• Electrokinetic potential refers to a potential difference in a liquid characterizing electrochemical equilibrium on interfaces.
• Zeta potential is the charge that is located at the slipping point of a particle in the shear plane.
• Zeta potential is the Colloidal chemistry.
• It is usually denoted using the Greek letter zeta (ζ) hence ζ-potential.
• (ζ), is the potential difference between the dispersion medium and the stationary layer of fluid attached to the dispersed particle.
• Zeta Potential is the potential difference across an electrostatic double layer of ions that surround a solid particle dispersed in a polar liquid. In short, it is a measure of the surface charge of a particle.
• The electric potential at the boundary of the double layer is known as the Zeta potential of the particles and has values that typically range from +100 mV to - 100 mV
The document discusses the properties of food colloids and emulsions. It describes the electrical double layer that forms around colloidal particles when dispersed in a medium. The zeta potential, which is the electric potential at the boundary of the double layer, determines whether particles will repel or attract each other. A high zeta potential leads to stability as particles repel, while a low zeta potential allows particles to flocculate. The document outlines several factors that influence zeta potential such as pH and ionic strength of the medium.
This document outlines objectives and concepts related to colloids and their importance in environmental engineering. It discusses the electrical double layer theory of colloidal surface charge and how colloids can be destabilized through processes like increasing ionic strength or adjusting pH. It also addresses turbidity in water supplies and its environmental significance.
Stabilization of emulsion via electrostaticLing Ling Ng
This document discusses the stabilization of emulsions via electrostatic forces. It defines emulsions as dispersions of one liquid in another immiscible liquid, and describes the electrical double layer that forms around dispersed droplets consisting of surface charges and layers of counterions. The document outlines DLVO theory, which states that emulsion stability is determined by a balance between attractive van der Waals forces and repulsive electrostatic forces. It also discusses how zeta potential measurement relates to stability, and how pH and ionic strength can affect zeta potential and thus the stability of emulsions.
Stabilization of emulsion via electrostaticLing Ling Ng
This document discusses the stabilization of emulsions via electrostatic forces. It defines emulsions as dispersions of one liquid in another immiscible liquid, and describes the electrical double layer that forms around dispersed droplets consisting of surface charges and layers of counterions. The document outlines DLVO theory, which states that emulsion stability is determined by a balance of attractive van der Waals forces and repulsive electrostatic forces. It also discusses how zeta potential measurement relates to stability, and how pH and ionic strength can affect zeta potential and thus the stability of emulsions.
This document provides an introduction to coagulation in water treatment and describes an atomic force microscopy study of bacterial interactions. It discusses the coagulation process and how coagulants work by reducing particle repulsion through charge neutralization. The document then describes growing and immobilizing E. coli bacteria to study bacterial interactions using atomic force microscopy under varying conditions of coagulants like aluminum sulfate and sodium chloride. The goal is to better understand bacterial interactions at the nano-scale to optimize coagulation processes.
Module 1 e (theory of disperse system).pptxDipti Nigam
1) The document discusses key concepts related to disperse systems including particle properties, surface and interfacial phenomena, and instability and stabilization.
2) Particle properties like shape and size distribution impact properties like viscosity, packing stability, and drug delivery. Surface charge and interfacial forces including van der Waals, electrical double layer, and DLVO theory also influence stability.
3) Instability occurs when attractive forces outweigh repulsive forces due to changes in surface energy. Stabilization techniques add electrostatic or steric repulsion to prevent aggregation. The zeta potential and energy barrier height indicate stability according to DLVO theory.
The document discusses coagulation and flocculation in water treatment. It explains that colloidal particles carry an electrokinetic charge that causes them to repel each other and prevent aggregation. Coagulation aims to reduce or eliminate this charge. The double layer model describes the ionic environment around charged colloids, with a Stern layer of firmly attached ions and a diffuse layer of ions in equilibrium with the solution. The thickness of the double layer depends on ion concentration and type. Zeta potential measures the electrical potential at the boundary between the Stern and diffuse layers, and indicates the strength of repulsive forces between particles.
This theory is explain by Derjaguin , Landau , Verway , Overbeek So it is known as DLVO Theory.
According to this theory , The forces on colloidal particles in a dispersion medium are due to –
1. Electrostatic Repulsion
2. London type Vander Waals Attraction
This document discusses colloids and factors that influence the stability of disperse systems such as suspensions. It covers topics like classification of colloids, sedimentation rates, DLVO theory, effects of electrolytes, and factors that influence stability. Suspension preparations are discussed, including issues like sedimentation, caking, and Ostwald ripening. Methods to improve stability include using flocculating agents and modifying the zeta potential.
Module 1 e (theory of disperse system).pptxDipti Nigam
The document discusses key concepts related to disperse systems, including:
- Particle properties like shape and size distribution impact properties like viscosity, packing, and stability.
- Surface charge and interfacial phenomena like van der Waals forces, electrical double layers, and zeta potential determine whether attractive or repulsive forces dominate between particles.
- The DLVO theory describes how the total interaction potential (VT) is determined by a balance of attractive van der Waals forces (VA) and repulsive electrostatic forces (VR), with stability requiring the maximum repulsion (Vmax) to exceed ~50 mV.
- Systems can be stabilized against instability through electrostatic or steric repulsion between particles.
1) Colloidal particles can be stabilized through Brownian motion if particle collisions do not result in sticking.
2) The key forces between colloidal particles include van der Waals attraction, electrostatic repulsion, steric repulsion, and solvation forces.
3) The stability of colloids is determined by factors such as salt concentration, particle charge (zeta potential), particle size, and addition of flocculating agents which can reduce zeta potential leading to aggregation.
Colloids are dispersions of particles between 1-1000 nanometers in diameter. Thomas Graham first distinguished colloids from crystalloids based on their ability to diffuse through membranes. Colloids exhibit unique optical, kinetic, and electrical properties due to their intermediate size. They scatter light, undergo Brownian motion, carry surface charges, and more. The behavior and stability of colloidal dispersions can be influenced by electrolytes, protective macromolecules, and coacervation of oppositely charged particles.
It is the electrokinetic potential in colloidal dispersions.
Zeta potential is the potential difference between the dispersion medium and the stationary layer of fluid attached to the dispersed particle.
When a colloidal suspension is placed in an electrical field, the colloidal particles move in one direction (toward the positive pole).
The counter ions move is another direction (toward the negative pole).
The electric potential developed at the solid liquid interface is called Zeta (ζ )potential.
Zeta potential is not equal to surface potential.
Zeta potential is less than electro chemical potential.
Increasing the concentration of electrolytes in the solution results in the decrease in thickness of double layer.
Thickness is also influenced by increasing valency of ions.
Isoelectric point:
At this point electrolyte concentration is maximum, thickness of double layer becomes neligible . Particle replusive force minimum. Zeta potential is equal to zero.
This document provides an overview of suspensions, including their classification, properties, formulation, and stability. Key points include:
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- Particle size, concentration, and Brownian motion influence sedimentation rates. Flocculated particles settle faster but are easier to redisperse than deflocculated particles.
- Stable suspensions are formulated using vehicles to
Pharmaceutical dispersed systems consist of a dispersed particulate phase and a continuous dispersion medium. They are classified based on particle size as molecular, colloidal, or coarse dispersions. Colloidal systems exhibit optical properties like the Tyndall effect and light scattering. They demonstrate kinetic properties including Brownian motion, diffusion, and osmotic pressure. Colloidal particles often carry an electric charge, forming an electric double layer that can electrostatically stabilize the system. The physical stability of colloids depends on a balance of electrical repulsive forces and attractive van der Waals forces between particles.
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Zeta
1. Zeta Potential
An Introduction in 30 Minutes
Introduction
Zeta potential is a physical property
which is exhibited by any particle in
suspension. It can be used to
optimize the formulations of
suspensions and emulsions.
Knowledge of the zeta potential can
reduce the time needed to produce
trial formulations. It is also an aid in
predicting long-term stability.
Colloid Science
Three of the fundamental states of
matter are solids, liquids and gases. If
one of these states is finely dispersed
in another then we have a ‘colloidal
system’. These materials have special
properties that are of great practical
importance.
There are various examples of
colloidal systems that include
aerosols, emulsions, colloidal
suspensions and association colloids.
In certain circumstances, the
particles in a dispersion may adhere
to one another and form aggregates
of successively increasing size, which
may settle out under the influence of
gravity. An initially formed aggregate
is called a floc and the process of its
formation flocculation. The floc may or
may not sediment or phase separate.
If the aggregate changes to a much
denser form, it is said to undergo
coagulation. An aggregate usually
separates out either by sedimentation
(if it is more dense than the medium)
or by creaming (if it less dense than
the medium). The terms flocculation
and coagulation have often been used
interchangeably. Usually coagulation
is irreversible whereas flocculation
can be reversed by the process of
deflocculation. Figure 1 schematically
represents some of these processes.
Figure 1: Schematic diagram
showing various mechanisms where
stability may be lost in a colloidal
dispersion
Colloidal Stability and
DVLO Theory
The scientists Derjaguin, Verwey,
Landau and Overbeek developed a
theory in the 1940s which dealt with
the stability of colloidal systems.
DVLO theory suggests that the
stability of a particle in solution is
dependent upon its total potential
energy function VT. This theory
recognizes that VT is the balance of
several competing contributions:
VT = VA + VR + VS
VS is the potential energy due to the
solvent, it usually only makes a
marginal contribution to the total
potential energy over the last few
nanometers of separation. Much more
important is the balance between VA
and VR, these are the attractive and
repulsive contributions. They
potentially are much larger and
operate over a much larger distance
VA = -A/(12 π D2)
where A is the Hamaker constant and
D is the particle separation. The
repulsive potential VR is a far more
complex function.
VR = 2 π ε a ζ2 exp(-κD)
where a is the particle radius, π is the
solvent permeability, κ is a function of
the ionic composition and ζ is the zeta
potential.
Figure 2(a): Schematic diagram of the
variation of free energy with particle
separation according to DVLO theory.
DVLO theory suggests that the
stability of a colloidal system is
determined by the sum of these van
der Waals attractive (VA) and
electrical double layer repulsive (VR)
forces that exist between particles as
they approach each other due to the
Brownian motion they are undergoing.
This theory proposes that an energy
barrier resulting from the repulsive
force prevents two particles
approaching one another and
adhering together (figure 2 (a)). But if
the particles collide with sufficient
energy to overcome that barrier, the
1 Zetasizer Nano series technical note MRK654-01
2. attractive force will pull them into
contact where they adhere strongly
and irreversibly together.
Therefore if the particles have a
sufficiently high repulsion, the
dispersion will resist flocculation and
the colloidal system will be stable.
However if a repulsion mechanism
does not exist then flocculation or
coagulation will eventually take place.
Figure 2(b): Schematic diagram of the
variation of free energy with particle
separation at higher salt concentrations
showing the possibility of a secondary
minimum.
If the zeta potential is reduced (e.g. in
high salt concentrations), there is a
possibility of a “secondary minimum”
being created, where a much weaker
and potentially reversible adhesion
between particles exists (figure 2 (b)).
These weak flocs are sufficiently
stable not to be broken up by
Brownian motion, but may disperse
under an externally applied force such
as vigorous agitation.
Therefore to maintain the stability of
the colloidal system, the repulsive
forces must be dominant. How can
colloidal stability be achieved? There
are two fundamental mechanisms that
affect dispersion stability (figure 3):
• Steric repulsion - this involves
polymers added to the system
adsorbing onto the particle
surface and preventing the
particle surfaces coming into
close contact. If enough polymer
adsorbs, the thickness of the
coating is sufficient to keep
particles separated by steric
repulsions between the polymer
layers, and at those separations
the van der Waals forces are too
weak to cause the particles to
adhere.
• Electrostatic or charge
stabilization - this is the effect on
particle interaction due to the
distribution of charged species in
the system.
Each mechanism has its benefits for
particular systems. Steric stabilization
is simple, requiring just the addition of
a suitable polymer. However it can be
difficult to subsequently flocculate the
system if this is required, the polymer
can be expensive and in some cases
the polymer is undesirable e.g. when
Figure 3: Steric and electrostatic
stabilization mechanisms of
colloidal dispersions
a ceramic slip is cast and sintered, the
polymer has to be ‘burnt out’. This
causes shrinkage and can lead to
defects.
Electrostatic or charge stabilization
has the benefits of stabilizing or
flocculating a system by simply
altering the concentration of ions in
the system. This is a reversible
process and is potentially
inexpensive.
It has long been recognised that the
zeta potential is a very good index of
the magnitude of the interaction
between colloidal particles and
measurements of zeta potential are
commonly used to assess the stability
of colloidal systems.
Origins of Surface Charge
Most colloidal dispersions in aqueous
media carry an electric charge. There
are many origins of this surface
charge depending upon the nature of
the particle and it’s surrounding
medium but we will consider the more
important mechanisms.
Ionisation of Surface Groups
Dissociation of acidic groups on the
surface of a particle will give rise to a
negatively charged surface.
Conversely, a basic surface will take
on a positive charge (figure 4). In both
cases, the magnitude of the surface
charge depends on the acidic or basic
strengths of the surface groups and
on the pH of the solution. The surface
charge can be reduced to zero by
suppressing the surface ionisation by
decreasing the pH in case of
negatively charged particles (figure
4(a)) or by increasing the pH in the
case of positively charged particles
(figure 4(b)).
Figure 4(a): Origin of surface
charge by ionisation of acidic
groups to give a negatively
charged surface
Figure 4(b): Origin of surface
charge by ionisation of basic
groups to give a positively charged
surface
2 Zetasizer Nano series technical note MRK654-01
3. Differential loss of ions from
the crystal lattice
As an example, consider a crystal of
silver iodide placed in water. Solution
of ions occurs. If equal amounts of
Ag+ and I- ions were to dissolve, the
surface would be uncharged. In fact
silver ions dissolve preferentially,
leaving a negatively charged surface
(figure 5). If Ag+ ions are now added
the charge falls to zero. Further
addition leads to a positively charged
surface.
Figure 5: Origin of surface charge
by differential solution of silver
ions from a AgI surface
Adsorption of charged species
(ions and ionic surfactants)
Surfactant ions may be specifically
adsorbed on the surface of a particle,
leading, in the case of cationic
surfactants, to a positively charged
surface (figure 6(a)) and, in the case
of anionic surfactants, to a negatively
charged surface (figure 6(b)).
Figure 6(b): Origin of surface
charge by specific adsorption
of an anonic surfactant. R =
hydrocarbon chain
The Electrical
Double Layer
The development of a nett charge at
the particle surface affects the
distribution of ions in the surrounding
interfacial region, resulting in an
increased concentration of counter
ions, ions of opposite charge to that of
the particle, close to the surface. Thus
an electrical double layer exists round
each particle.
Zeta Potential
The liquid layer surrounding the
particle exists as two parts; an inner
region (Stern layer) where the ions
are strongly bound and an outer
(diffuse) region where they are less
firmly associated. Within the diffuse
layer there is a notional boundary
inside which the ions and particles
form a stable entity. When a particle
moves (e.g. due to gravity), ions
within the boundary move it. Those
ions beyond the boundary stay with
the bulk dispersant. The potential at
this boundary (surface of
hydrodynamic shear) is the zeta
potential (figure 7).
The magnitude of the zeta potential
gives an indication of the potential
stability of the colloidal system. If all
the particles in suspension have a
large negative or positive zeta
potential then they will tend to repel
each other and there will be no
tendency for the particles to come
together. However, if the particles
have low zeta potential values then
there will be no force to prevent the
Figure 7: Schematic representation of
zeta potential
particles coming together and
flocculating.
The general dividing line between
stable and unstable suspensions is
generally taken at either +30 or -30
mV. Particles with zeta potentials
more positive than +30 mV or more
negative than -30 mV are normally
considered stable. However, if the
particles have a density different form
the dispersant, they will eventually
sediment forming a close packed bed
(i.e. a hard cake).
Factors Affecting Zeta Potential
(1) pH
In aqueous media, the pH of the
sample is one of the most important
factors that affects its zeta potential. A
zeta potential value on its own without
defining the solution conditions is a
virtually meaningless number.
Imagine a particle in suspension with
a negative zeta potential. If more
alkali is added to this suspension then
the particles tend to acquire more
negative charge. If acid is added to
this suspension then a point will be
reached where the charge will be
Figure 6(a): Origin of surface
charge by specific adsorption
of a cationic surfactant. R =
hydrocarbon chain
3 Zetasizer Nano series technical note MRK654-01
4. neutralised. Further addition of acid
will cause a build up of positive
charge. Therefore a zeta potential
versus pH curve will be positive at low
pH and lower or negative at high pH.
There may be a point where the plot
passes through zero zeta potential.
This point is called the isoelectric
point and is very important from a
practical consideration. It is normally
the point where the colloidal system is
least stable.
A typical plot of zeta potential versus
pH is shown in figure 8. In this
example, the isoelectric point of the
sample is at approximately pH 5.5. In
addition, the plot can be used to
predict that the sample should be
stable at pH values less than 4
(sufficient positive charge is present)
and greater than pH 7.5 (sufficient
negative charge is present). Problems
with dispersion stability would be
expected at pH values between 4 and
7.5 as the zeta potential values are
between +30 and -30mV.
2. Conductivity
The thickness of the double layer (κ-1)
depends upon the concentration of
ions in solution and can be calculated
from the ionic strength of the medium.
The higher the ionic strength, the
more compressed the double layer
becomes. The valency of the ions will
also influence double layer thickness.
A trivalent ion such as Al3+ will
compress the double layer to a
greater extent in comparison with a
monovalent ion such as Na+.
Inorganic ions can interact with
charged surfaces in one of two
distinct ways (i) non-specific ion
adsorption where they have no effect
on the isoelectric point. (ii) specific ion
adsorption, which will lead to a
change in the value of the isoelectric
point. The specific adsorption of ions
onto a particle surface, even at low
concentrations, can have a dramatic
effect on the zeta potential of the
particle dispersion. In some cases,
specific ion adsorption can lead to
charge reversal of the surface.
3. Concentration of a formulation
component
The effect of the concentration of a
formulation component on the zeta
potential can give information to assist
in formulating a product to give
maximum stability. The influence of
known contaminants on the zeta
potential of a sample can be a
powerful tool in formulating the
product to resist flocculation for
example.
Electrokinetic Effects
An important consequence of the
existence of electrical charges on the
surface of particles is that they
interact with an applied electric field.
These effects are collectively defined
as electrokinetic effects. There are
four distinct effects depending on the
way in which the motion is induced.
These are:
Electrophoresis: the movement of a
charged particle relative to the liquid it
is suspended in under the influence of
an applied electric field
Electroosmosis: the movement of a
liquid relative to a stationary charged
surface under the influence of an
electric field
Streaming potential: the electric field
generated when a liquid is forced to
flow past a stationary charged surface
Sedimentation potential: the electric
field generated when charged
particles sediment
Electrophoresis
When an electric field is applied
across an electrolyte, charged
particles suspended in the electrolyte
are attracted towards the electrode of
opposite charge. Viscous forces
acting on the particles tend to oppose
this movement. When equilibrium is
reached between these two opposing
forces, the particles move with
constant velocity.
The velocity is dependent on the
strength of electric field or voltage
gradient, the dielectric constant of the
medium, the viscosity of the medium
and the zeta potential.
The velocity of a particle in a unit
electric field is referred to as its
electrophoretic mobility. Zeta potential
is related to the electrophoretic
mobility by the Henry equation:-
4 Zetasizer Nano series technical note MRK654-01
UE = 2 ε z f(κa)
3η
where UE = electrophoretic mobility, z
= zeta potential, ε = dielectric
constant, η = viscosity and f(κa) =
Henry’s function.
The units of κ, termed the Debye
length, are reciprocal length and κ-1 is
often taken as a measure of the
“thickness” of the electrical double
layer. The parameter ‘a’ refers to the
radius of the particle and therefore κa
measures the ratio of the particle
radius to electrical double layer
thickness (figure 9). Electrophoretic
determinations of zeta potential are
most commonly made in aqueous
media and moderate electrolyte
concentration. F(κa) in this case is
1.5, and this is referred to as the
Smoluchowski approximation.
Therefore calculation of zeta potential
Figure 8: Typical plot of zeta potential
versus pH showing the position of the
isoelectric point and the pH values
where the dispersion would be
expected to be stable
5. from the mobility is straightforward for
systems that fit the Smoluchowski
model, i.e. particles larger than about
0.2 microns dispersed in electrolytes
containing more that 10-3 molar salt.
For small particles in low dielectric
constant media (eg non-aqueous
media), f(κa) becomes 1.0 and allows
an equally simple calculation. This is
referred to as the Huckel
approximation.
Figure 9: Schematic illustrating
Huckel and Smoluchowski's
approximations used for the
conversion of electrophoretic mobility
into zeta potential
Measuring Electrophoretic
Mobility
The essence of a classical micro-electrophoresis
system is a capillary
cell with electrodes at either end to
which a potential is applied. Particles
move towards the electrode, their
velocity is measured and expressed in
unit field strength as their mobility.
Early methods involved the process of
directly observing individual particles
using ultra-microscope techniques
and manually tracking their progress
over a measured distance. This
procedure, although still being used
by many groups world wide, suffers
from several disadvantages, not least
that of the strenuous effort required to
make a measurement, particularly
with small or poorly scattering
particles. The technique used in
Malvern’s Zetasizer Nano range of
instruments is laser Doppler
electrophoresis in combination with
M3-PALS.
The M3-PALS Technique
The Zetasizer Nano Series uses a
combination of laser Doppler
velocimetry and phase analysis light
scattering (PALS) in a patented
technique called M3-PALS to
measure particle electrophoretic
mobility. Implementation of M3-PALS
enables even samples of very low
mobility to be analysed and their
mobility distributions calculated.
PALS can give an increase in
performance of greater than 100
times that associated with standard
measurement techniques. This allows
the measurement of high conductivity
samples, plus the ability to accurately
measure samples that have low
particle mobilities, such as samples
dispersed in non-aqueous solvents.
Low applied voltages can now be
used to avoid any risk of sample
effects due to Joule heating.
Further information discussing the
techniques of laser Doppler
electrophoresis and M3-PALS can be
found in various articles available on
the Malvern Instruments web-site
Optical Configuration of a
Zeta Potential Instrument
A zeta potential measurement system
comprises of six main components
(figure 10). Firstly, a laser 1 is used
to provides a light source to illuminate
the particles within the sample. For
zeta potential measurements, this
light source is split to provide an
incident and reference beam. The
incident laser beam passes through
the centre of the sample cell 2, and
the scattered light at an angle of
about 13o is detected 3. When an
electric field is applied to the cell, any
particles moving through the
measurement volume will cause the
intensity of light detected to fluctuate
with a frequency proportional to the
particle speed and this information is
passed to a digital signal processor 4
and then to a computer 5. The
Zetasizer Nano software produces a
frequency spectrum from which the
electrophoretic mobility and hence
zeta potential is calculated. The
intensity of the detected, scattered
light must be within a specific range
for the detector to successfully
measure it. This is achieved using an
attenuator 6, which adjusts the
intensity of the light reaching the
sample and hence the intensity of the
scattering. To correct for any
differences in the cell wall thickness
and dispersant refraction,
compensation optics 7 are installed
to maintain optimum alignment.
Figure 10: Optical configuration of
the Zetasizer Nano series for zeta
potential measurements
References
Derjaguin, B.V. and Landau, L. (1941)
Acta Physiochim. URSS, 14, 633.
Verway, E.J.W. and Overbeek, J. Th.
G. (1948) Theory of the Stability of
Lyophobic Colloids, Elsevier,
Amsterdam.
Hunter, R.J. (1988) Zeta Potential In
Colloid Science: Principles And
Applications, Academic Press, UK.
5 Zetasizer Nano series technical note MRK654-01
6. Shaw, D.J. (1992) Introduction To
Colloid And Surface Chemistry,
Butterworth Heinemann, UK.
Everett, D.H. (1994) Basic Principles
Of Colloid Science, The Royal Society
of Chemistry, UK.
Ross, S. and Morrison, I.D. (1988)
Colloidal Systems and Interfaces,
John Wiley and Sons, USA.
Lyklema, J. (2000) Fundamentals of
Interface and Colloid Science: Volume
1 (Fundamentals), Academic Press,
UK.
Measuring Zeta Potential: Laser
Doppler Electrophoresis, Technical
Note available from
www.malvern.co.uk
Measuring Zeta Potential Using
Phase Analysis Light Scattering
(PALS), Technical Note available from
www.malvern.co.uk
Measuring Zeta Potential: A New
Technique, Technical Note available
from www.malvern.co.uk
Simplifying the Measurement of Zeta
Potential Using M3-PALS, Technical
Note available from
www.malvern.co.uk
Malvern Instruments Ltd
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more information at www.malvern.co.uk
6 Zetasizer Nano series technical note MRK654-01