Surface Measurement Systems

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Benjamin Paul
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1 Surface Measurement Systems Euro Food s Water, Brussels, Belgium: March 2006 pattwool@smsuk.co.uk

2 SMS - History Company formed in 1992/university spin-off Hotbed of innovation 10 Ph.D. s First Product Dynamic Vapour Sorption (DVS) 1993 DVS Microscope and Organic Vapour Options 1996 First commercial Inverse Gas Chromatograph 2000 Vapour Generator Instrument 2001 DVS High Throughput 2005

3 DVS Introduction Materials and Moisture How do materials interact with moisture in the environment? Effects stability, performance and safety of many materials. Isotherm - Equilibrium moisture content as a function of Relative Humidity. How much is taken up. Kinetics Moisture transport properties, how fast.

4 Limitations of Existing Techniques Saturated salt solutions: Very slow: weeks for one isotherm using static gravimetric saturated salt solution techniques. Labour intensive if many humidity levels required. Not able to study kinetics of sorption/desorption. Limited accuracy/precision.

5 DVS - Flowing Gas System Weigh sample continuously. Fully automated gravimetric instrument. Fast kinetics. Caking. Dynamic system - constant flow of gas ensures optimal mass transfer rate to and from sample - i.e. reaches equilibrium faster.

6 Dynamic Vapour Sorption Experiments may be completed in less than 24 hours. Entire system enclosed in temperature controlled environment - prevents condensation. Small sample size ( typically 1-100mg ) reduces time needed to establish equilibrium. Continuous monitoring of mass allows computer to decide when equilibrium is reached. Full control and monitoring of sample environment.

7 DVS Flow - Microbalance Digital recording ultra-microbalances: DVS Advantage - 1 Sample size up to 1.5 gm Mass change of +/- 150 mg with 0.1 µg resolution. DVS Advantage - 2 Ideal for larger food samples.

8 Kinetics of Moisture Sorption of Microcrystalline Cellulose % Change in Mass Relative Humidity (%) Time/mins 0 Moisture sorption behaviourofmicro crysta line ce lulose at25c-sorption onlyshown

9 Microcrystalline Cellulose - Isotherms Change in Mass (%) Desorption Sorption Target RH (%)

10 Water Uptake Kinetics of Monosodium glutamate Kinetics of water sorption for monosodium glutamate dm - dry TargetRH Change In Mass (%) - Dry Target RH (%) Time in minutes

11 Spray Dried Milk Powder - Kinetics Collapse of Amorphous Lactose Component Relative Humidity (%) Time/mins 0

12 DVS- HT - The Next Generation

13 DVS-HT the High Thoughput Solution All new design. Fully automated operation. Multi-sample, high speed isotherm generation. 10 to 20 fold increase in efficiency over existing systems and technology. Designed for routine sorption analysis. No compromise data quality.

14 Carousel and sample pan

15 Avicel 10 HT samples Moisture Uptake for Avicel at 25C : 10 Sample Pans % Change in Mass Sam ple 1 Sam ple 2 Sam ple 3 Sam ple 4 Sam ple Target % P/Po Sam ple Sam ple 7 Sam ple 8 Sam ple 9 20 Sample % P/Po W ater Time / min 0

16 Avicel 10 HT samples + 1 DVS-1 sample Water Sorption Isotherms for Avicel at 25C: 10 DVS-HT Samples and 1 DVS-1 Samples % Increase in Mass DVS-1 HT Pan 1 HT Pan 2 HT Pan 3 HT Pan 4 HT Pan 5 HT Pan 6 HT Pan 7 HT Pan 8 HT Pan 9 HT Pan % Saturated Partial Pressure of Water

17 DVS-HT Dramatic lactose photos 29.1%RH versus 59.0%RH

18 Spray Dried Lactose/DVS-HT Dynamic Vapour Sorption High Throughput (DVS-HT) data Different amorphous contents % Amorphous+duplicate ChangeInMass(%)- Dry DVS - TheSorptionSolution Target% RelativeHumidity Time/mins 75% Amorphous +duplicate 50% Amorphous 25% Amorphous 0% Amorphous SurfaceMeasurementSystemsLtdUK Relativehumidityin%

19 Sustained Release Capsules 90% RH t=0 hours 90% RH t=10 hours 1000µm

20 DVS - Applications Fast and Accurate Sorption Isotherms High Throughput option now available Caking, shelf-life and hygroscopicity measurements Dr. Philip Attwool pattwool@smsuk.co.uk

DVS Intrinsic Compact and Economical Dynamic Vapor Sorption System

DVS Intrinsic Compact and Economical Dynamic Vapor Sorption System The easy-to-use solution to complex water sorption challenges from SMS: High quality water isotherms and efficient water activity measurements