DVS Application Notes

DVS Application Note 01 – Validation of Relative Humidity using Saturated Salt Solutions pdf
DVS Application Note 02 – Moisture Sorption of EC Standard Reference Material RM 302 on a DVS-1 Instrument DVS Application Note 02 PDF pdf
DVS Application Note 10 – Direct Visualization of Moisture Induced Morphological Transformations using a combination of DVS and in-situ Colour Video Microscopy DVS Application Note 10 PDF pdf
DVS Application Note 46 – Combining Raman Spectroscopy with Gravimetric Vapour Sorption Analysis for Pharmaceutical Materials DVS Application Note 46 PDF pdf
DVS Application Note 57 – Characterization of Wheat Straw for Biofuel Application DVS Application Note 57 PDF pdf
DVS Application Note 104 – Vapor Sorption Properties of Building Materials using Gravimetric Sorption Instrumentation – an Overview DVS Application Note 104 PDF pdf

Application Notes by Request

DVS Application Note 03 Polymorphism in Spray Dried Lactose – The presence of amorphous material in spray-dried powders is of great interest to the pharmaceutical industry. Even small amounts can significantly change the physico-chemical properties of materials. This application note describes the use of DVS water vapor sorption analysis to demonstrate the behavior of a highly amorphous lactose powder using a rapid humidity ramping method.
DVS Application Note 05 Adsorption of High Concentrations of Organic Vapours on Activated Carbon – This application note describes how a standard DVS gravimetric vapor adsorption analyzer system may be used to study the adsorption of organic vapours at high concentrations on activated carbons and other porous solid substrates.
DVS Application Note 07 Measurement of Diffusion of Liquids and Vapours Through Real Polymer Tube Packaging Devices – Measuring diffusion and permeation of vapours and liquids through real packaging devices is important of both pharmaceutical and food packaging solutions. In this study DVS vapor sorption analysis was used to measure the diffusion of saturated vapours through real polymer packaging systems.
DVS Application Note 08 Moisture Sorption of Coffee Granules studied using DVS and in-situ Video Microscopy – Moisture sorption properties of food materials are fundamental considerations for improving stability, storage and product use.  In this application note we use the integrated video-microscope in a DVS Advantage vapor sorption analyser to describe gravimetric changes in coffee granules while ramping humidity.
DVS Application Note 09 Measuring the Moisture Sorption Kinetics of Cements using DVS – Moisture uptake in cements is an important factor in its long term storage stability and is typically measured by storing large containers in controlled conditions over long periods of time.  In this application note we show how Dynamic Vapor Sorption (DVS) analysis is a rapid method for obtaining the same measurements.
DVS Application Note 11 Moisture Stability of Powdered Milk Formulations – Safe storage life of powdered milk formulations depends on moisture stability particularly if exposed to prolonged periods of high humidity and temperature.  In this note we performed moisture sorption analysis using DVS to determine if unbound moisture would be released, which could encourage microbial growth.
DVS Application Note 12 Absolute Measurement of Moisture Diffusion into Blister Packaging Systems – Blister packaging systems are often used as a primary barrier to the ingress of moisture into moisture sensitive products. These blister packaging systems often show substantial differences in barrier properties to the unformed polymer film due to localised defects/stresses in the polymer material as a result of the forming process. The DVS results may be used to assess batch-to-batch quality variations, or may be used to predict product life under a wide range of storage conditions for example.
DVS Application Note 13 Moisture Sorption of Hydrophobic Pharmaceutical Substances – DVS is commonly employed to measure the moisture sorption properties of hygroscopic pharmaceutical materials. The affinity of these materials for the sorption of moisture is often due to a degree of amorphous character present in the material. Highly crystalline materials such as salts of drugs may have very low affinities for moisture sorption due to the low surface energy of the particles formed during the crystallisation process.
DVS Application Note 14 Moisture Sorption of Activated Carbon – Activated carbons are used throughout industry in various applications including environmental air filtration to solvent and heavy metal recovery.  In this study we measure the moisture sorption properties of activated carbon using DVS analysis.
DVS Application Note 16 Calculation of Diffusion Constants in Thin Polymer Films using DVS – Moisture diffusion in thin polymer films is of interest to a variety of different industrial sectors including packaging materials and membrane technologies.  In this application note we calculated the diffusion constants using the gravimetric measurements made by DVS moisture sorption analysis.
DVS Application Note 17 Measurement of the Surface Energies of Powders using Organic Vapour Probes
and DVS – Measuring the surface properties of powders is important for many industries.  In this application note we present a novel method for determining the surface energy of powders by measuring the adsorption isotherms of organic vapours using a DVS vapour sorption analyser.
DVS Application Note 18 Measuring BET Surface Areas Using Organic Probe Molecules – As powder processsing increases in importance, measuring the surface properties of those powders increases.  This application note describes the measurement of BET surface area using organic sorption analysis in a DVS Advantage at ambient temperature and pressure.
DVS Application Note 19 Determining the Heat of Sorption on Organic and Inorganic Powders using DVS – Understanding the interactions between vapours and solid materials is very important to a number of industries including pharmaceuticals, foods, flavours, porous materials and catalysts. Dynamic Vapour Sorption (DVS) allows a simple and accurate determination of the heat of sorption for a wide range of solid-vapour systems. This paper describes heat of sorption measurements on an alumina and a crystalline lactose sample using water and 1-butanol.
DVS Application Note 20 Caking of Lemon Flavour Powdered Drink Using DVS Humidity Cycling – The moisture sorption properties of foods are critical for their shelf-life stability. This is especially true for powdered products which are vulnerable to either temperature or humidity shocks. Products can cake, become sticky and collapse thus rendering them unsaleable. This paper demonstrates the effect of relative humidity pulse length and cycling methods at different temperatures.
DVS Application Note 21 Moisture Sorption on Tobacco of Various Origins – Moisture sorption properties are important for determining the shelf life stability of tobacco products.  Once tobacco becomes wet it can lose taste, added flavor or lose combustibility.  This application note demonstrates the application of the DVS Advantage-2 for high mass tobacco sample size using relative humidity steps and cycling methods.
DVS Application Note 22 A Simple Shelf Life Prediction of Crackers – The moisture sorption properties of foods are critical for their shelf-life stability. This is especially true for materials like biscuits or crackers which are vulnerable to either temperature or humidity shocks. These products can take up a high amount of water, melt and collapse thus rendering them unsalable.  This application note analyses the moisture sorption properties of cracker material to determine shelf life stability.
DVS Application Note 23 The Water Sorption Properties of Ramyun Noodles – Moisture uptake in noodles is important for predicting stability and quality after storage.  Excess water uptake may cause poor texture, dissolution or mould growth.  In this application note we used DVS with a video microscope to analyse the stability of food materials at various humidities.
DVS Application Note 24 Moisture Sorption on Commercial Humic Acids – The sorption properties of humic acids are important and are widely studied and reported in the literature.  This application note describes how DVS moisture sorption analysis is used to study humic acids to better understand the possible complexation of water by humic acids.  Batch to batch variability and the effects of humidity perturbations were also studied.
DVS Application Note 25 Moisture Sorption on Bohemian Brown Coal Humic Acids – This application note continues our study on humic acids by measuring the water sorption by humic acids of Bohemian brown coal origin.
DVS Application Note 26 Isotherm Types and Adsorption Mechanisms of Solvents on Pharmaceutical Excipients – The interaction of organic solvents and water with pharmaceutical powders is highly important for the understanding of solvent-based processes, e.g. wet-granulation, crystallization, drying or prediction of product stability and shelf life. For these reasons information about the adsorption mechanism of these solvents on powder surfaces is required. This information can often be obtained from the shape of the vapour sorption isotherm.
DVS Application Note 27 Hygroscopicity of Japanese Green Tea Powder – The water uptake in food products is key to determining their stability. In many cases, excess water uptake will lead to caking, dissolution or even mould growth. The Dynamic Vapour Sorption (DVS) machine enables real time measurements to be undertaken of the water sorption kinetics on food materials over a wide range of relative humidities (from 0% RH to 98% RH) and temperatures.
DVS Application Note 28 Water pickup in Monosodium Glutamate – The water uptake in flavour delivery systems is key to their performance. Monosodium glutamate (MSG) is widely used in hot, humid Asian countries where flavour enhancers can become extremely unstable. The Dynamic Vapour Sorption (DVS) machine is designed to take real time gravimetric measurements on the kinetics of water sorption of food products. This encompasses the typical heat and humidity conditions for storage of food materials and will give directions to product developers in their search for greater product stability.
DVS Application Note 29 Moisture Desorption of Creams and Calculation of Diffusion Constants – Cream formulations are widely used in a variety of applications, from cosmetics such as hand cream and suntan cream to medical uses such as antiseptic cream. The moisture content of creams and the rate of moisture loss under different conditions are important for determining factors such as the texture, the feeling on the skin and the efficacy of the cream. In this application note, we describe the measurement of moisture (and organic vapour) loss in creams using DVS and apply it to the calculation of diffusion coefficients.
DVS Application Note 30 Calculation of Diffusion Constants in a Pharmaceutical Powder using DVS – Vapour diffusion rates are of interest in a wide range of applications including: polymers, pharmaceuticals, flavours, and foods. This application note describes the measurement of water vapour diffusion coefficient and its activation energy of diffusion into an amorphous pharmaceutical powder by measuring water vapour sorption kinetics using a DVS instrument.
DVS Application Note 31 Measurement of Moisture Ingress in Microelectronic Device Packaging – In this paper DVS ET(Elevated Temperature) is used to study the moisture sorption of a standard 16 pin DIL IC package under precisely controlled temperature and humidity conditions to demonstrate the capacity of the instrument to overcome the challenges of measuring very small weight changes in samples over a long period of time under highly aggressive conditions such as 85% RH and 85°C .
DVS Application Note 32 Accelerated Moisture Sorption Measurements by DVS Microsample Analysis – A key requirement in the development of new pharmaceutical products is the screening of large numbers of candidate substances for potentially undesirable physical properties such as moisture sorption/stability. This application note describes the approach to reduce analysis times by up to ten times by utilising the very high sensitivity of the ultra-balance employed in the DVS instrument.
DVS Application Note 33 Moisture Sorption Measurements on a Lyophilised Bovine Serum Albumin Sample – In the development of solid-state dosage forms of biopharmaceuticals the effect of moisture on the stability and structure have become increasingly important. This paper investigates the affects of bovine serum albumin (BSA) loading on the moisture sorption behaviour with co-lyophilised sugars. For maltose and sucrose, increasing BSA content increased the moisture-induced crystallization humidity. For mannitol, the water sorption results indicate a higher mannitol amorphous content is possible with higher BSA loadings.
DVS Application Note 34 A New Gravimetric Method to Calculate Low Levels of Amorphous Content – A new method to quantify low amorphous contents using DVS was developed using organic vapours. The difference in sorption capacity between crystalline and amorphous phases was used to determine amorphous contents below 1%. This new method is compared with four established methods for measuring amorphous contents using gravimetric vapour sorption techniques.
DVS Application Note 35 Determining the Moisture-Induced Glass Transition in an Amorphous Pharmaceutical Material – A new method to determine the onset relative humidity for a glass transition in an amorphous material was developed using the DVS. Water vapour can act as a plasticising agent in amorphous materials, causing a recrystallisation event below the glass transition temperature. This method calculates the threshold relative humidity for this moisture-induced glass transition at a particular temperature.
DVS Application Note 36 Investigation of Hydrate Formation and Loss Using DVS – Water vapour can associate with solids in many ways, including adsorb on the surface, absorb deep into the bulk structure, chemisorb to the surface, act as a plasticizing agent forcing a glass transition and potentially inducing spontaneous recrystallization, or chemically react with the solid. Dynamic Vapour Sorption (DVS) allows the fast and accurate determination of hydrate/solvate stoichiometry for a wide range of solid-vapour systems. This paper describes hydrate loss and formation on naloxone HCl and nedocromil sodium samples.
DVS Application Note 37 Hysteresis Effects in Vapour Sorption – Hysteresis effects in vapour sorption on solid materials can have different causes. Four different mechanisms responsible for fundamental hysteresis effects are described and discussed in this paper. Although hysteresis can occur as a combination of different causes, misinterpretation occurs quite regularly in literature. For this reason it is important to analyse the hysteresis shape carefully.
DVS Application Note 38 Determination of Mesopore Size Distribution by Organic Vapour Sorption – Alumina samples have been investigated by organic vapour sorption. Mesoporous structures were studied and pore size distributions have been calculated based on octane adsorption experiments at ambient conditions. The results were in good agreement with standard low temperature nitrogen adsorption measurements.
DVS Application Note 39 Measuring Moisture Sorption and Diffusion Kinetics on Proton Exchange Membranes Using the DVS – Proton Exchange Membrane Fuel Cells (PEMFC) are an expanding area of research for use as low pollution power generators for mobile and stationary applications. Dynamic Vapour Sorption (DVS) analysis allows the fast and accurate determination of water sorption isotherms and diffusion kinetics over a wide temperature and humidity range. This paper describes the water sorption behaviour on three Nafion® based fuel cell membranes.
DVS Application Note 40 Using the DVS to Study the Water Sorption Properties of Multi-Component Systems – In this study Dynamic Vapour Sorption (DVS) was used to measure the water sorption isotherms of two pharmaceutical formulations and were compared to the moisture isotherms of the individual components. The first formulation was granules consisting of microcrystalline cellulose, hydroxypropylcellulose (HPC), and Lovastatin. The second mixture consisted of co-lyophilised bovine serum albumin (BSA) and mannitol.
DVS Application Note 41 Using the DVS to Study the Formation of Solvates – Pharmaceutical solids can often form solvated species which can affect the material’s physical and chemical stability. Dynamic Vapour Sorption (DVS) allows the fast and accurate determination of solvate stoichiometry for a range of solid-vapour systems. This paper describes acetone solvate formation of anhydrous carbamazepine and ethanol solvation of erythromycin. A 1:1 carbamazepine-acetone solvate and a 1:3 erythromycin-ethanol solvate were observed in this study.
DVS Application Note 42 Using the DVS to Investigate Moisture-Induced Crystallization Kinetics – Many amorphous solids will revert to more theremodynamically stable crystalline forms if exposed to conditions above their glass transition.  The rate of crystallization can be influenced by temperature, relative humidity and other neighbouring materials.  We performed water sorption analysis using a DVS instrument to study the crystallization behaviouor of amourphous spray-dried lactose over a wide range of temperature and humidity conditions.
DVS Application Note 43 Determination of Surface Energetics of Mineral Aggregates used in Asphalt by DVS – The quality of asphalt depends strongly on the affinity of the mineral aggregates to the bitumen binder. This affinity is directly related to the surface energetics of the individual components. Dynamic gravimetric vapour sorption is an accurate and reliable method for the characterisation of solid powders. In the current study dispersive and specific (acid-base) contributions to the surface energy have been measured for six different mineral aggregates.
DVS Application Note 44 Determining Amorphous Contents without a Standard: Hydrate/Solvate Stoichiometry – A method to quantify low amorphous contents using DVS was developed based on the formation of a stoichiometric hydrate or solvate. If only the amorphous phase hydrates/solvates upon exposure to the appropriate vapour, then the amorphous content of a partially amorphous material can be determined. This method does not require any amorphous standards. Theophylline hydrate formation and carbamazepine-acetone solvate formation were used as examples.
DVS Application Note 45 Investigation of Desolvation Kinetics Using the DVS – The rate of solvation/desolvation for pharmaceutical solids can often affect the material’s physical and chemical stability. Dynamic Vapour Sorption (DVS) allows the fast and accurate determination of solvation/desolvation kinetics for a range of solid-vapour systems. This paper describes acetone desolvation behaviour for a 1:1 carbamazepine:aceteone solvate.
DVS Application Note 46 Combining Raman Spectroscopy with Gravimetric Vapour Sorption Analysis for Pharmaceutical Materials – Raman spectroscopy is a widely used physical characterization technique used in the pharmaceutical industry. The combination of Raman spectroscopy and Dynamic Vapour Sorption (DVS) allows for a more complete understanding of vapour-solid interactions for pharmaceutical materials as it relates to structural properties. This paper overviews the DVS-Raman capabilities and gives several examples
DVS Application Note 47 Determination of True Density by Dynamic Vapour Sorption – The versatility and impact of Dynamic Vapour Sorption (DVS) for the true density measurements of solid powder materials have been investigated. True density measurements on different amounts of Lactose and Avicel (microcrystalline cellulose) samples were successfully determined using DVS and a gas Pycnometer for comparison.
DVS Application Note 49 Measuring Water Vapor Flux Across Model Proton Exchange Membranes – Water content and flux are important properties for proton exchange membrane fuel cell performance. This application note describes the use of a novel cell to measure vapour flux or permeation rates across polymer films. Nafion® membranes were used as model membranes. Water vapour flux measurements were performed at three temperatures for three Nafion® membranes.
DVS Application Note 50 An Overview of Dynamic and Gravimetric Vapor Sorption Vacuum System – SMS DVS Vacuum system makes use of Dynamic and gravimetric vacuum methods which offer a number of advantages over other sorption methods for studying vacuum adsorption processes. SMS DVS Vacuum instrument can offer measurements on vapour pressure and heat of evaporation of solids, low pressure vapour/gas sorption and vacuum drying.
DVS Application Note 51 Gas Capture and Vapour Separation by Microporous Materials – Metal Organic Frameworks (MOFS) as well as inorganic solids are of great importance due to their high adsorption capacity and surface reactivity and are used for various applications. Dynamic vapour sorption (DVS) methods have been a very useful tool for the characterization of these properties using water and organic vapours at process relevant temperatures.
DVS Application Note 52 Vapour Permeability of Porous Materials using Payne Diffusion Cell – Vapour permeability in porous materials is of interest to a variety of different industrial sectors including packaging materials, membrane technologies, tissue engineering scaffolds etc. This application note describes the measurement of moisture vapour transmission rates (MVTR) through porous materials (i.e. silicone membranes/human skin and electrospun polymer fibre mats), using a Payne type diffusion cell and DVS instrument.
DVS Application Note 53 Moisture Sorption and Pore Collapse of Coals – Porosity is a common characteristic of many natural and man-made systems. The pores in these systems can have significant impact on the way materials behave and react to conditions in the environment. Coals are known to be porous in nature. This application note investigates the moisture sorption properties and pore collapse of different coal samples.
DVS Application Note 54 Detecting and Modelling Porosity in Natural and Engineered Materials – Many common materials and foods contain pores and pore networks. These can greatly impact material behaviour. Nature is full of examples where pores are an integral part of living organisms and inert materials.  Dynamic Vapour Sorption (DVS) analysis can be a valuable technique in detecting and characterizing porosity in these systems.
DVS Application Note 55 Measurement of Moisture Uptake Capacity in Human Hair Using Dynamic Vapor Sorption Technique – Water content is one of the most important parameters controlling the condition of skin and hair fibres. Dynamic Vapour Sorption (DVS) analysis was used to investigate the water sorption performance of three types of human hair classified as; Asian (undamaged), Caucasian (undamaged), and bleached Caucasian (damaged) hair.
DVS Application Note 56 Measuring TEWL or Moisture Flux Across Artificial Skin – The measurement of water flux through human skin is important in the cosmetics and pharmaceutical industries. It plays an important role in the evaluation of treatments for skin injuries and diseases. In this note we demonstrate how to measure this quantity using the DVS line of instruments and a Payne type diffusion cell.
DVS Application Note 57 Characterisation of Wheat Straw for Bio-fuel Application – One of the crucial steps of producing bio-ethanol from wheat straw is its pre-treatment which should facilitate the economic feasibility and yield efficient conversion into biofuel. This pre-treatment is expected to increase the accessible chemical sites of the straw to increase convertibility in subsequent hydrolysis and fermentation steps. Dynamic Vapour Sorption (DVS) analysis and UV were used to assess the wheat straw pre-treatment and sugar yield, respectively.
DVS Application Note 58 Use of DVS-NEAR IR Technique for Material Characterization – The combination of dynamic vapour sorption and near infrared spectroscopy ( DVS- NIR) has been considered a novel technique for studying various materials and making in-depth analysis into their sorption/desorption properties. The investigation under this technique would provide a better understanding of solid-state reactions and establish the relationship between the stability of materials and their structural changes
DVS Application Note 59 Investigation of Channel Hydrate Formation and Loss Using the DVS – Dynamic Vapour Sorption (DVS) allows the fast and accurate determination of channel hydrate formation and loss. Channel hydrates typically exhibit characteristic water sorption isotherm behaviour. This paper illustrates channel hydration/dehydration using an active pharmaceutical ingredient (API).
DVS Application Note 60 Iso-activity Analysis of Phenol Crystals – An iso-activity is essentially the inverse of an isotherm. It records the equilibrium uptake at different temperatures and constant vapor concentration. A combination of Raman Spectroscopy and Dynamic Vapour Sorption (DVS) iso-activity analysis has been used to study Phenol crystals.
DVS Application Note 61 Characterizing the Restoration Materials for Historic Buildings Using Dynamic Vapor Sorption Technique – It is important to choose the right building materials for restoration of buildings and heritage structures. Old and new materials with near identical properties, especially relating to moisture ingress and water holding capacity are desirable to avoid ominous deterioration. DVS studies on various materials have been conducted to obtain their hygroscopic behaviour which are indicative of their suitability at site.
DVS Application Note 103 Organic Solvent Sorption using a Dynamic Vapor Sorption Instrument-an Overview – Dynamic Vapour Sorption (DVS) has long been used for investigating the interaction of water vapour with solid materials. However, the versatility and impact of DVS can be greatly expanded by also studying organic vapour sorption phenomena. This overview application note summarises several examples of using organic vapours with the DVS: solvate formation, amorphous contents, BET surface areas, porosity, and surface energies.
DVS Application Note 104 Vapour Sorption Properties of Building Materials using Gravimetric Sorption Instrumentation – an Overview – Dynamic Vapour Sorption (DVS) has long been used for investigating the interaction of water and organic vapours with solid materials. The versatility and impact of DVS has particular importance in the study of building materials. This overview application note summarises several examples of using DVS to study cements, wood, insulation, and other building materials.
DVS Application Note 108 Amorphous Content Determination using Amorphous and Crystalline Standards – This application note will discuss methods to measure amorphous contents of pharmaceutical materials, focusing on the DVS method devised by Mackin et al. Amorphous contents can be determined using this method via measurement of solvent uptake before and after a crystallization event with a limit of detection as low as 0.5% w/w.

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