Routine Maintenance Taking Samples Sample Insertion Unattended Operation Thermal Analysis Guide Tips and Hints for Routine Analysis Editorial Dear Reader Since the first experiments by Henry Louis Le Chatelier in 1887 thermal analysis has developed to a group of measuring techniques undispensable for material characterization of polymers, metals and inorganics, oils and fats, pharmaceuticals as well as food A major breakthrough was the invention of heat flow DSC in 1955 by S L Boersma The heat flow principle is still applied by present day instruments and reached its top with the recent introduction of the Flash DSC by METTLER TOLEDO The model Flash DSC allows ultra high heating rates of up to 2 400 000 K/min in the temperature range of -95°C up to maximum 500 °C The availability of powerful computer hardware and software influenced thermoanalytical methods enormously It simplified method setup and instrument operation and turned curve evaluation and result calculation into common and easily understandable tasks However, thourough thermal analysis knowledge and diligent instrument operational skills remain essential to achieve meaningful and precise results This guide presents some solutions to perform thermal analysis tests safely and easily in the daily routine METTLER TOLEDO Disclaimer The information contained in this guide is based on the current knowledge and experience of the authors The guide represents selected, possible application examples The experiments were conducted and the resulting data evaluated in our lab with the utmost care using the instruments specified in the description of each application The experiments were conducted and the resulting data evaluated based on our current state of knowledge However, this guide does not absolve you from personally testing its suitability for your intended methods, instruments and purposes As the use and transfer of an application example are beyond our control, we cannot accept responsibility therefore When chemicals, solvents and gases are used, the general safety rules and the instructions given by the manufacturer or supplier must be observed ® ™ All names of commercial products can be registered trademarks, even if they are not denoted as such Content Content Introduction Taking Samples Starting a Measurement Sample Insertion Unattended Measurement 10 Ensure Measurement Accuracy 11 Conclusions 13 More Supporting Information – Stay up to Date 14 METTLER TOLEDO Thermal Analysis Guide Introduction Introduction When it comes to analyze many samples in limited time, analytical instruments have to be well "calibrated" and need to perform at their best These requests are typical for the quality control of received goods, intermediate specimen taken from a production line, produced parts and failure analysis and material research Furthermore, operation of the instruments should be as simple and safe as possible Basic maintenance tasks executed periodically assure good working conditions of the instruments A seamless workflow takes care that an analysis can be done without any interrupting delays Automation accessories help avoiding error-prone manual steps The METTLER TOLEDO Thermal Analysis Excellence systems offer new possibilities to achieve exactly such targets Test methods include several work steps and can be set to high automation levels if desired Few basic skills and a minimum of training are necessary to conduct a complete thermal analysis Routine tests can be executed with one click from the instrument's touch screen terminal without the need to have access to the controlling PC Efficient and reliable day 24 hours operation is supported by a sample changer robot Thanks to its clever design, the robot offers flexible crucible handling and reliable single axis movement It is factory endurance tested On the following pages we will show selected routine maintenance tasks as easy and convenient tools to achieve good thermal analysis results METTLER TOLEDO Thermal Analysis Guide Taking Samples Taking Samples A sample has to be representative, clean and original Thus, good laboratory and good manufacturing practice guidelines (GLP, GMP) point out sampling rules to assure that final results are meaningful and characteristic For thermal analysis, sample size and shape are two additional important aspects Size When other analytical techniques such as titration or pH value can accommodate sample of up to 100 g or 100 mL, small sized samples can undergo thermal analysis only Hence, the selection of the right part of the sample is crucial for the analysis Shape Flat surface to allow for good thermal contact Thermal analysis Typical sample size DSC 5–50 milligrams Flash DSC 20–100 nanograms TGA 10–1000 milligrams TMA Depends on mode and sample, e.g Dilatometry of polymers: x x millimeters (LxWxT) DMA Depends on sample, clamp and instruments For point bending of thermosets: 50 x x millimeters (LxWxT) Table 1: Typical sample size for thermal analysis For TGA measurements in addition, the sample's minimum weight has to be considered The minimum weight depends on the type of the built-in balance and the uncertainty requirements for a certain weight step or the weight of the residue Also the upper sample size limit is defined based on available crucible volume, desirable heating rate and analysis time Both values can be entered into the method in form of sample limits This means that an operator having prepared too small or too large a sample is not allowed to start the measurement Good thermal analysis measurements depend also on the correct choice of crucibles and lids Typical crucible materials are aluminum, alumina, platinum, steel, gold plated steel, copper, etc They are selected according to the maximum temperature and to avoid Figure 1: Selection of crucibles for thermal analysis or minimize reactions with the sample Lids seal the crucible hermetically to avoid evaporation of the sample and to avoid interferences with the surrounding atmosphere Lids with a small hole e.g a pre-punched 50 µm hole, allow for a self-generated atmosphere in the crucible due to restricted exchange with the ambient On the other hand, open crucibles without a lid or with a lid with a big hole allow the ambient atmosphere to come into contact with the sample METTLER TOLEDO Thermal Analysis Guide Taking Samples Crucible material Volume µL Recommended use Limits Aluminum 40 Default for DSC 640 °C Aluminum 20 For DSC of polymer films, disks and powders 640 °C Platinum 40 TGA and DSC, better DSC signal than alumina >640 °C Gold 40 high chemical resistance 750 °C Stainless steel 120 Medium pressure DSC applications 250 °C, MPa Stainless steel 40 High pressure DSC applications 400 °C, 15 MPa Alumina 70 Default for TGA 2000 °C Alumina 900 TGA for big sample volumes 2000 °C Table 2: Selection of TA crucibles and recommended use How different types of samples are filled into crucibles can be watched in the DSC sample preparation video www.mt.com/ta-videos More details, tips and hints see Thermal Analysis in Practice, Application Handbook, chapters 7.3, 9.3, 10.3 and 11.3 Figure 2: Weighing samples for DSC tests on a microbalance METTLER TOLEDO Thermal Analysis Guide Starting a Measurement Starting a Measurement To assure safe and easy starting of analyses, the thermal analysis instruments and methods are prepared accordingly Instruments: Keep instruments idle at starting temperature, assure gas supply, check instrument performance before analyses are due Methods: Select optimal measurement parameters such as heating rate, end temperature, sample size limits, Select suitable evaluation range and procedure, Store method to be available for One Click™ Methods started with One Click™ provide increased safety and efficiency: • No confusion about methods to apply • No operating errors • No time consuming method entry • Minimized error-prone manual data entry The unique One Click functionality introduced by METTLER TOLEDO to a variety of instruments allows easy and safe starting of predefined measuring methods After one click on the instruments’ color touchscreen display the method is started automatically or a next screen asks for further data displaying entry fields for sample name, sample weight and position if a sample robot is used To avoid transcription errors and simplify the task at the utmost we recommend a barcode reader for sample identification entry Figure 3: One ClickTM screen METTLER TOLEDO Thermal Analysis Guide Sample Insertion Sample Insertion Sample insertion to DSC and TGA instruments can be done in two ways: Manual insertion DSC and TGA systems standout by their intelligent ergonomic design This means in particular that a tray with the prepared crucibles can be placed very near to the sensor area where the measurement takes place Hand rests with ergonomically shaped and soft touch coated surfaces support the operator Thus, operators can easily and safely insert the samples into the measurement cell Figure 4: DSC oven ready for manual sample entry Automatic insertion using the sample robot The main advantages of a sample robot are unattended operation for increased efficiency, extended working period to overcome regular shifts and improved repeatability thanks to reduced operator influence The METTLER TOLEDO sample robot can process up to 34 samples even if every sample requires a different method and a different crucible The robot can remove the protective crucible lid from the crucible or pierces the lid of hermetically sealed aluminum crucibles immediately before measurement This unique feature prevents the sample taking up or losing moisture between weighing-in and measurement It also protects oxygen-sensitive samples from oxidation Thanks to a clever design, the piercing pin does not contact the sample and refrains from contamination of the next sample Please see the sample changer robot in action at Figure 5: Sample robot handling several types of crucibles www.mt.com/ta-automation For DMA measurements, the sample needs to be fixed by clamps and then inserted Several insertion modes are applied in TMA measurement Sample insertion modes for TMA Penetration or expansion measurement Figure 6a: Sample placed on sample support and topped by sensor probe Tension measurement Figure 6b: Sample fixed by clamps and hanging in sample support Swellling measurement Figure 6c: Sample in crucible topped by sensor probe METTLER TOLEDO Thermal Analysis Guide Unattended Measurement Unattended Measurement Unattended measurements are a perfect set for error free, safe and reliable experiments All experimental parameters have been entered beforehand to the method and stored for repetitive use Thus, any recall of the method assures correct execution of the test Once the measurement is started, the method is worked off automatically Many features of METTLER TOLEDO's Thermal Analysis Excellence instruments contribute nicely to safe and unattended measurements Here is some selection: • FlexCal®, a functionality of the STARe software, takes care that always the correct calibration data are applied to calculate results It automatically considers variations of gases, crucibles, heating rate etc from one measurement to the next This results in accurate and precise measurements • The gas flow is programmed within the method Thus, no manual flow adjustments are necessary and FlexCal is able to take it into account • Set the TGA instrument for automatic buoyancy compensation This is an easy and effective measure to achieve accurate TGA results Buoyancy compensation reduces the experimental time needed to produce accurate results by more than 50%: • It eliminates the need to run and subtract blank curves • It makes waiting for cooling time between blank and sample measurement obsolete Figure 7: Excellent agreement between the time saving buoyancy compensated and a conventional TGA measurement • After the measurement itself is finished and the resulting curve is recorded, a preprogrammed macro evaluates the effect(s) of interest and performs a conformity check against given limits A result text can be displayed, e.g "The sample has passed" The evaluated curve including results can be printed and/or transferred to a LIMS system automatically Even a good/bad distinction can be executed automatically • When a measurement has ended, the method can be set to inform the user by email This is especially helpful, when operating an instrument manually and one is waiting to insert the next sample Figure 8: Preconfigured gas supply which does not need any user interaction Another aspect of unattended measurement is the application of a sample changer robot It extends the period of unattended operation considerably, even out of regular lab working hours METTLER TOLEDO's sample robot for DSC and TGA stores up to 34 samples Its universal gripper handles various crucible types It even applies lid piercing when specified in the method METTLER TOLEDO Thermal Analysis Guide 10 Ensure Measurement Accuracy Ensure Measurement Accuracy A calibration, also called a "check", determines the difference of a measured value from a reference value The calibration provides information about the current state of the instrument Calibration data must be within the acceptable error limits The adjustment changes the instrument parameters in a way that the measured value agrees with the reference value Adjustments are only made, if the deviation evidenced by the calibration is unacceptable The measured signal (ordinate) and the physical properties in conjunction with the abscissa of a diagram need to be calibrated Typically, one should calibrate temperature and heat flow for DSC and weight for TGA Ordinate • DSC: Heat flow in Watt, normalized heat flow in Joule per gram • TGA: Mass in g (automatically performed in the electronic microbalance, optional manually) • TMA and DMA: Length (displacement) in mm and force in N Abscissa • Temperature in °C, K or F • Time (e.g for isothermal measurements) in second or minutes Since time is derived from the quartz clock of a microprocessor, it is extremely accurate and calibration may be omitted Table 3: Ordinates and abscissae The acceptable deviations of the measured from the reference values depend on the deviation which is later allowed for the measurements of samples, i.e the acceptable measurement uncertainty Also the temperature range of the calibration depends on the range later applied to the sample testing For instance it is not necessary to calibrate a DSC system up to 660 °C (aluminum point) if the sample measurements always end at 200 °C As a check interval, we suggest a period of once a month If the results are repeatedly within acceptable error limits, this interval can be doubled If several measurements with unacceptable results are obtained, the interval should be reduced to half However, the frequency of checks (calibrations) depends on several factors e.g internal regulations, legal requirements, the frequency of use of the instruments, the applications, etc For some users it may be enough to calibrate once per half year, others may require daily calibration In any way, it is recommended to document calibrations to record the calibration history After an adjustment, one should always perform a calibration to verify that correct values are obtained Any combination of a measuring module, type of crucible and atmosphere can be used to perform calibrations and adjustments With the STARe software of METTLER TOLEDO the calibration parameters are stored in the database Example methods are available in the database for the most important standard combination of measurement parameters (e.g DSC, 40 µL Al crucible, air) METTLER TOLEDO Thermal Analysis Guide 11 Ensure Measurement Accuracy Indium Check ^exo Sample: Indium, 6.2800 mg Integral -181.13 mJ normalized -28.84 Jg^-1 Onset 156.57 °C 20 mW The DSC module is within specifications (27.85…29.05 J/g, 156.3…156.9 °C) Figure The results of this DSC calibration are within the permissible error limits An adjustment is not necessary More details see Thermal Analysis in Practice, Application Handbook, chapter 6.5 METTLER TOLEDO Thermal Analysis Guide 12 Conclusions Conclusions Instrument maintenance, test method setup and sample preparation are important pillars of good measurements They have to be carried out carefully and contribute equally to accurate and reliable results They also are prerequisite to lab efficiency and enable seamless workflows Sampling and sample preparation Start experiment with One Click™ Sample identification with barcode Measurement of sample Correct experimental data including - Automatic load of most current calibration data - Automatic gas delivery and control - Automatic buoyancy compensation (in case of TGA) Automatic evaluation of the resulting curve Automatic results calculation e.g for Pass/fail decision, material conformity check, curing rate Printout of the result and/or Transfer to a LIMS system Table 4: A seamless thermal analysis workflow Thermal Analysis Excellence instruments support users in many ways from crucible selection to instrument check and measurement accuracy They help to safely achieve the ultimate target of accurate and reliable test results METTLER TOLEDO Thermal Analysis Guide 13 More Supporting Information More Supporting Information – Stay up to Date Take advantage of our variety of publications and online resources to keep you and your business up to date and well informed 8.1 Videos We provide web-based technical videos on different topics You can watch them at any convenient time and place www.mt.com/ta-videos 8.2 Webinars We provide web-based seminars (webinars) on different topics You can participate in on-demand webinars at any convenient time and place Live webinars offer the added benefit of allowing you to ask questions and discuss points of interest with METTLER-TOLEDO specialists and other participants www.mt.com/webinars Webinars dedicated to thermal analysis are available here www.mt.com/ta-webinars 8.3 Applications and UserComs We offer comprehensive application support for thermal analysis methods Thermal ananlysis applications www.mt.com/ta-applications Thermal analysis UserCom www.mt.com/ta-usercoms 39 Thermal Analysis Information for Users User Com Dear Customer, Contents 1/ 2014 This year, we celebrate two milestone anniversaries, namely 50 years of METTLER TOLEDO thermal analysis and 20 years of UserCom With this in mind, we are delighted to announce a new STARe software version and three new instruments Details can be found in the News section We are convinced that thermal analysis will continue to play an important role in the testing, characterization and development of materials, and in research As in the past, new technologies will lead to new innovations and open up new application areas, in the same way as we have recently seen with the Flash DSC In the twentieth year of UserCom, we hope that we can once again surprise you with interesting application examples and look forward to your comments and feedback TA Tip Curve interpretation, Part 2: Variation of heating and cooling rates Dr Jürgen Schawe In practice, heating measurements are frequently performed at just one heating rate The properties of many substances and materials however depend on their production and storage conditions In such cases, important additional information can be obtained by simply varying the heating and cooling rates These possibilities are illustrated with the aid of typical examples 40 Thermal Analysis Information for Users - Curve interpretation, Part 2: Variation of heating and cooling rates News User Com Dear Customer, Contents 2/2014 Welcome to the 40th edition of UserCom Our well-known thermal analysis journal was first published in spring 1995 Since then it has appeared regularly twice a year in English and several other languages We thank all our readers and the many authors who have presented exciting news and developments from the world of thermal analysis and so contributed to its continued success We would be delighted to hear your thoughts and comments about UserCom In the meantime, we hope you will enjoy reading the interesting articles, tips, and latest news from METTLER TOLEDO on thermal analysis TA Tip - Curve interpretation, Part 3: DSC curves and curves from other thermal analysis techniques - STARe System enhancements - The TGA-IST-GC/MS system – unprecedented detailed insight 10 - 50 years of innovation in thermal analysis 11 - Cooling with the latest instruments from Huber 13 - Characterization of shape memory alloys by DSC and DMA, Part 1: DSC analysis - Quantos HPD – A clever handheld solution for powder dosing 15 - Investigation of the bouncing behavior of two rubber balls 15 Applications - Characterization of the growth of intermetallic phases by DSC 10 - Measurement of vapor pressure curves and the enthalpy of vaporization of liquids by HPDSC - Characterization of biomass using TGA/DSC coupled to a mass spectrometer 18 16 - Composition of water-in-oil ammonium nitrate emulsions using TGA and DSC - Determination of the adiabatic Time to Maximum Rate by DSC for thermal safety assessment 20 18 - Determination of the water content of an ionic liquid Applications - Thermomechanical analysis of natural and cosmetically treated hair 22 - Determination of heat capacity by temperature-modulated DSC at temperatures above 700 °C 24 Dates - Exhibitions - Courses and Seminars 26 27 24 Dates - Exhibitions 26 - Courses and Seminars 27 METTLER TOLEDO Thermal Analysis Guide 14 More Supporting Information 8.4 Handbooks You are welcome to purchase the following handbooks which spread TA knowledge and experience and carefully explain details Application handbook Pages Order number Thermal Analysis in Practice 327 51 725 244 Thermosets 315 51 725 069 51 725 067 51 725 068 Thermoplastics 150 51 725 002 Elastomers 275 51 725 061 51 725 057 51 725 058 Polymers – Selected Applications 38 300 76 210 Pharmaceuticals 100 51 725 006 Food 50 51 725 004 Evolved Gas Analysis (EGA) 65 51 725 056 Validation in Thermal Analysis 232 51 725 141 Details Volumes and Volume Volume Volumes and Volume Volume www.mt.com/ta-handbooks METTLER TOLEDO Thermal Analysis Guide 15 Good Measuring Practices Five Steps to Improved Measuring Results The five steps of all Good Measuring Practices guidelines start with an evaluation of the measuring needs of your processes and their associated risks Using this information, Good Measuring Practices provide straight forward recommendations for selecting, installing, calibrating and operating laboratory equipment and devices • Preservation of the accuracy and precision of results • Compliance with regulations, secure audits • Increased productivity, reduced costs • Professional qualification and training Good Thermal Analysis Practice™ Fast and secure thermal analysis results – with the help of GTAP™ Dependable analysis of thermal material properties starts long before daily routines in the laboratory: a requirements-based selection of the system as well as professional installation, qualification and training form the basis for dependable and error-free thermal analysis measurements METTLER TOLEDO offers comprehensive support for all steps to ensure that you invest in the right area and minimize risks with targeted efforts: It's a long term solution www.mt.com/gtap Learn more about Good Measuring Practices program www.mt.com/gp www.mt.com For more information Mettler-Toledo International Inc Laboratory Division CH-8606 Greifensee, Switzerland Subject to technical changes © 05/2015 Mettler-Toledo AG Global MarCom Switzerland [...]... spread TA knowledge and experience and carefully explain details Application handbook Pages Order number Thermal Analysis in Practice 3 27 51 72 5 244 Thermosets 315 51 72 5 069 51 72 5 0 67 51 72 5 068 Thermoplastics 150 51 72 5 002 Elastomers 275 51 72 5 061 51 72 5 0 57 51 72 5 058 Polymers – Selected Applications 38 300 76 210 Pharmaceuticals 100 51 72 5 006 Food 50 51 72 5 004 Evolved Gas Analysis (EGA) 65 51 72 5...Ensure Measurement Accuracy 6 Ensure Measurement Accuracy A calibration, also called a "check", determines the difference of a measured value from a reference value The calibration provides information about the current state of the instrument Calibration data must be within the acceptable error limits The adjustment changes the instrument parameters in a way that the... results They also are prerequisite to lab efficiency and enable seamless workflows Sampling and sample preparation Start experiment with One Click™ Sample identification with barcode Measurement of sample Correct experimental data including - Automatic load of most current calibration data - Automatic gas delivery and control - Automatic buoyancy compensation (in case of TGA) Automatic evaluation of... system Table 4: A seamless thermal analysis workflow Thermal Analysis Excellence instruments support users in many ways from crucible selection to instrument check and measurement accuracy They help to safely achieve the ultimate target of accurate and reliable test results METTLER TOLEDO Thermal Analysis Guide 13 More Supporting Information 8 More Supporting Information – Stay up to Date Take advantage... measurements with unacceptable results are obtained, the interval should be reduced to half However, the frequency of checks (calibrations) depends on several factors e.g internal regulations, legal requirements, the frequency of use of the instruments, the applications, etc For some users it may be enough to calibrate once per half year, others may require daily calibration In any way, it is recommended... measurements of samples, i.e the acceptable measurement uncertainty Also the temperature range of the calibration depends on the range later applied to the sample testing For instance it is not necessary to calibrate a DSC system up to 660 °C (aluminum point) if the sample measurements always end at 200 °C As a check interval, we suggest a period of once a month If the results are repeatedly within acceptable... Example methods are available in the database for the most important standard combination of measurement parameters (e.g DSC, 40 µL Al crucible, air) METTLER TOLEDO Thermal Analysis Guide 11 Ensure Measurement Accuracy Indium Check ^exo Sample: Indium, 6.2800 mg Integral -181.13 mJ normalized -28.84 Jg^-1 Onset 156. 57 °C 20 mW The DSC module is within specifications ( 27. 85…29.05 J/g, 156.3…156.9 °C) Figure... the twentieth year of UserCom, we hope that we can once again surprise you with interesting application examples and look forward to your comments and feedback TA Tip Curve interpretation, Part 2: Variation of heating and cooling rates Dr Jürgen Schawe In practice, heating measurements are frequently performed at just one heating rate The properties of many substances and materials however depend on... DSC calibration are within the permissible error limits An adjustment is not necessary More details see Thermal Analysis in Practice, Application Handbook, chapter 6.5 METTLER TOLEDO Thermal Analysis Guide 12 Conclusions 7 Conclusions Instrument maintenance, test method setup and sample preparation are important pillars of good measurements They have to be carried out carefully and contribute equally... material properties starts long before daily routines in the laboratory: a requirements-based selection of the system as well as professional installation, qualification and training form the basis for dependable and error-free thermal analysis measurements METTLER TOLEDO offers comprehensive support for all steps to ensure that you invest in the right area and minimize risks with targeted efforts: It's ... Analysis Guide Unattended Measurement Unattended Measurement Unattended measurements are a perfect set for error free, safe and reliable experiments All experimental parameters have been entered... trademarks, even if they are not denoted as such Content Content Introduction Taking Samples Starting a Measurement Sample Insertion Unattended Measurement 10 Ensure Measurement Accuracy... time between blank and sample measurement obsolete Figure 7: Excellent agreement between the time saving buoyancy compensated and a conventional TGA measurement • After the measurement itself