6 mpdp routine maintenance guide EN

Maintenance Guide Performance Verification Day-to-Day Routine Maintenance of Melting & Dropping Point Instruments Content Content Introduction Tips & Hints for Accurate Melting Point Determination Tips & Hints for Accurate Dropping & Softening Point Determination How to Clean the Dropping Point Furnace 11 Performance Verification with MP VPac 13 More Information 14 ™ 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 METTLER TOLEDO Automated Melting & Dropping Point Analysis Introduction Introduction For almost decades METTLER TOLEDO has provided instrumental solutions for the automatic determination of the thermal values melting point, dropping and softening point The MP and DP Excellence lines, METTLER TOLEDO’s latest release of compact instruments for thermal characterization, support the complete analytical workflow with innovative solutions In order to characterize a material aside from chemical analysis, primarily physical methods allow us to differentiate between, identify and classify substances or to describe quality aspects Thermal characteristics, such as melting and dropping point provide valuable and accessible information in this respect This guideline provides advice and tips for the routine maintenance of the melting point and dropping point instruments in the daily use The MP and DP Excellence lines consist of the following instruments: • Melting point: MP50, MP70, MP90 • Dropping and softening point: DP70, DP90 METTLER TOLEDO Automated Melting & Dropping Point Analysis Melting Point Determination Tips & Hints for Accurate Melting Point Determination A practical and rather easy way to check the performance of a melting point instrument is the comparison with standard reference samples A periodically repeated comparison reveals immediately if instruments deviate from the regular and required performance, if calibration is requested or even if service has to be done For comparison purposes several sets of standard reference materials are available 2.1 Melting Point Standards Overview The following table provides an overview of the melting point standards that are important for melting point determination The individual standards specify the measurement parameters, the experimental setup (e.g heating medium; oil bath or furnace), the capillary dimensions and the detection of the melting point event Some of the pharmacopeias offer their own reference substances that are recommended for use in the calibration/adjustment of the instrument The instruments of the MP Excellence line fully comply with these standards Name Detection point Heating rate [°C/min] Own references substances US Pharmacopeia USP 37-NF32 Melting range: Evaluation of collapse and clear point Yes, 6, range 83–237 °C British Pharmacopeia Meniscus point No Japanese Industrial Standard K 0064 Japanese Pharmacopeia 16th edition Clear point No Chinese Pharmacopeia Clear point 0.2 °C/min and °C/min Yes, 12, range 60 –280 °C International Pharmacopeia (WHO) Melting point: Evaluation of clear point Yes, 12, range 69–263 °C European Pharmacopeia 8th edition 8.2 chapter 2.2.60 Clear point No ASTM D1519-95 (2004) Clear point ± 0.2 °C/min No Table 1: Melting point standards overview 2.2 Melting Point Measurement Results The following tables include melting point test results of reference substances from two different suppliers, USP and WHO, that were measured with an MP90 For each reference substance, the measurement was obtained by taking the mean value of six capillaries The results reveal the excellent measurement accuracy and repeatability that can be achieved with MP Excellence instruments The basis of these measurements is careful sample preparation which can easily be achieved using the capillary filling tool METTLER TOLEDO Automated Melting & Dropping Point Analysis Figure 1: USP reference substances 2.2.1 USP References USP specifies that the measured melting range must a) lie within the specified minimum and maximum temperatures (e.g 81–83 °C for vanillin), and b) must not be broader than the specified admissible values (e.g 1.5 °C for vanillin) So, the permitted measured melting range for vanillin could be 81.0–82.5, 81.3–82.8 °C etc Name of USP reference substance Vanillin Assigned MR [°C] min/max Measured MR [°C] admissible range min/max range Repeatability [°C] 81.0–83.0 1.5 82.0–82.6 0.6 TA: 0.13 TC: 0.05 Phenacetin 134.3–136.0 1.5 135.0–135.5 0.5 TA: 0.05 TC: 0.00 Sulfanilamide 164.0–165.7 164.1–165.0 0.9 TA: 0.23 TC: 0.05 Sulfapyridine 190.0–192.0 1.5 191.1–191.9 0.9 TA: 0.05 TC: 0.04 Caffeine 235.6–237.5 235.6–236.1 0.5 TA: 0.07 TC: 0.07 Table 2: USP references (MR: melting range, Repeatability: capillaries) Six capillaries of each USP reference substance were measured simultaneously and the respective transmission curves were evaluated in the melting range mode, meaning the default parameters of points A and C were used Conclusions The accuracy and repeatability of the results obtained from the MP90 are excellent With each of the tested reference substances a melting range smaller than the admissible reference value was reached The absolute melting range values were all within the specification temperatures Hence, the MP90 instrument is ideally suited to determine melting points according to USP METTLER TOLEDO Automated Melting & Dropping Point Analysis Melting Point Determination 2.2.2 WHO References WHO reference substances are specified with a maximum permissible temperature range, in the same way as the METTLER TOLEDO reference substances The melting point criterion is the clear point C, when all solid material has been transformed into the liquid state Figure 2: WHO reference substances Name of WHO reference substance Assigned MR [°C] Measured MR [°C] Repeatability [°C] Azobenzene 69.0 (± 0.4) 69.0 TC: 0.22 Vanillin 83.2 (± 0.6) 83.3 TC: 0.17 Acetanilide 116.0 (± 0.3) 116.1 TC: 0.09 Phenacetin 136.0 (± 0.3) 135.7 TC: 0.15 Sulfapyridine 192.7 (± 1.2) 192.9 TC: 0.10 Saccharin 230.0 (± 0.5) 230.3 TC: 0.09 Table 3: WHO references (MR: melting range, Repeatability: capillaries) Conclusions The MP90 achieved excellent results also with the WHO reference substances The melting points of all tested references were within specifications The achieved repeatability was far better than the assigned values Thus, the MP90 is best suitable to measure melting points following WHO guidelines METTLER TOLEDO Automated Melting & Dropping Point Analysis Dropping & Softening Point Determination Tips & Hints for Accurate Dropping & Softening Point Determination The procedure to check the performance of dropping and softening point instruments is similar to the melting point instrument check However, more strict rules apply in terms of suitable reference materials measurement parameters 3.1 Instrument Performance Verification If we want to make sure that our dropping point instrument functions correctly, we need to verify its measurement accuracy The following section gives valuable tips and hints to help execute the performance verification correctly In order to check temperature accuracy we use reference substances and compare their nominal values, including tolerances, with the measured values ("calibration") If the measured temperature values are outside the values of the certified reference substance, the instrument needs to be adjusted ("adjustment") METTLER TOLEDO reference substances such as Figure 3: METTLER TOLEDO reference substances benzophenone, vanillin, benzoic acid and potassium nitrate provide certified temperature values that can be used for temperature calibration of the DP70 and DP90 furnaces It is highly recommended that METTLER TOLEDO reference substances are used for calibration and adjustment purposes of DP Excellence instruments The substances are securely identified with two barcodes showing the filling code and lot number The quality of the substances is guaranteed and is monitored by DSC measurement The DP70 and DP90 Excellence instruments include an automatic procedure that compares the measured value with the nominal value The basis for comparison is the thermodynamic melting point of the reference substance (referred to as calibration substance) that is detailed on the corresponding certificate and includes measurement uncertainty The thermodynamic melting point is the physically correct melting point temperature of the actual sample, not the furnace temperature, and is independent of the experimental setup The dropping point of a reference substance is not equal to the thermodynamic melting point as the measured temperature is actually the furnace temperature and not the sample temperature Therefore, the furnace temperature value needs to be adjusted using a correction value, which is stored for each reference substance in the instrument The correction factor is substance-specific and heatingrate dependent It corrects the measured furnace temperature to the thermodynamic melting point of the relevant substance The correction factors in the table are valid for a heating rate of 0.2 °C/min Figure 4: DP screen shot Entry field for correction factor and reference substance Reference substance Correction factor [°C] Benzophenone -1.2 Vanillin -1.5 Benzoic acid -1.4 Potassium nitrate -1.4 Table 4: Correction factors based on thermodynamic melting point METTLER TOLEDO Automated Melting & Dropping Point Analysis Dropping & Softening Point Determination Once this is done, the comparison between measured and nominal temperature values is given Furthermore the correction factor takes into account the viscosity of the molten reference sample that drops from the cup, which has an influence on the dropping point temperature The correction factors have been determined empirically by comparing the furnace temperature dropping point with the known thermodynamic melting point of the reference substance If the measured values of the reference substances are (a) within the nominal temperature value ranges, the instrument performance is ok (b) are outside of the nominal temperature value ranges, performance is not ok In this case, the instrument issues a warning It then needs to be adjusted 3.2 Sample Preparation The basis for comparable and reliable results in dropping point and softening point analysis is repeatable sample preparation This is why we recommend to use the accessory box of the DP instruments including the patented sample preparation tool 3.2.1 Excellence Accessory Box The DP accessory box is included in the standard delivery of the DP70 and DP90 It provides useful accessories for reliable sample preparation: • The DP sample preparation tool that enables efficient and clean filling of up to dropping and softening point cups with liquid or solid substances, including a handle to place or remove the tool's plate into an oven or a refrigerator • Two tamping rods to press ground solid samples into dropping or softening point cups • 2 softening and dropping point cups made of chromium-plated brass • 2 stainless steel balls according to ASTM D6090 • 2 cup lids with vent hole to close the sample-containing cup • 6 glass cups for collection of liquefied or softened samples during the respective tests • Sample carrier that holds two dropping or softening point cups with glass collectors and cup lids • A stand that holds two sample carriers • A spatula to transfer the sample into a cup or to remove excessive sample • A rod to remove excessive lubricant grease from a dropping point cup according to the procedure specified in ASTM D556 Cup lids Cups Spatula and rod Handle Balls Sample preparation tool Collector glass Tamping rod Reference substance Benzoic acid Stand METTLER TOLEDO Figure 5: DP accessory box Automated Melting & Dropping Point Analysis Sample carrier 3.2.2 Efficient and Reliable Sample Preparation: The Sample Preparation Tool The basis for comparable and reliable results in dropping point and softening point analysis is repeatable sample preparation With the DP Excellence sample preparation tool this crucial step is perfectly supported: • Efficient sample preparation as four cups can be prepared at a time • Handling errors are minimized and operational security maximized • Contamination of the outer surface of the sample cup is avoided which contributes to result reliability The sample preparation tool consists of four pieces: • A double-sided base plate that holds four dropping point cups on one side and four softening point cups on the other • A support disk with four holes • A disk-like funnel for powdered samples • A handle to carry the whole tool (not shown in the pictures) Dropping point cups are positioned on the side of the base plate with the deepest indentations The shallower indentations on the other side of the plate are used for positioning the softening point cups A support disk is used to fix the cups and to make the upper rim of the cup level with the surface The support disk therefore serves a threefold purpose: first to prevent the sample from contaminating the outer surface of the cups, second to facilitate the removal of excessive sample, and third to facilitate the complete filling of the sample cup with powdered samples 3.2.3 DP Excellence Sample Holder and Standard Compliant Cups Standardized dropping and softening point cups from METTLER TOLEDO are made of chromium-plated brass or aluminium The experimental setup required for an automatic dropping and softening point test consists of the sample-containing cup, closed with a lid, and a collection glass Figure 6: Work sequence with sample preparation tool underneath to collect the liquefied sample The sample carrier allows the efficient, simultaneous measurement of two samples, which are placed with the sample carrier into the DP furnace After test completion the sample carrier is removed from the furnace and securely placed on the stand to cool down to ambient temperature It is then quickly disassembled and the collection glasses are put into the waste with the aluminium dropping or softening point cups Cup lids prevent discharge of expanding sample, which avoids contamination of the Collection glass Cup Lids Stand Cups Figure 7: DP Sample holder and stand Figure 8: Dropping point cups Figure 9: Softening point cups METTLER TOLEDO Automated Melting & Dropping Point Analysis Dropping & Softening Point Determination furnace 10 Tedious and time-consuming work in dropping and softening point analysis involves cleaning the components after completion of the analysis Unhealthy, nonpolar solvents may be required in order to dissolve the sample residues The DP Excellence system provides disposable aluminium sample cups and glass sample-collectors that make cleaning unnecessary The post-treatment process is therefore significantly accelerated and the system is ready for the next measurements within a short time The DP Excellence solution is therefore much more efficient than other competitor systems that require complete cleaning of the sample holder prior to the next analysis METTLER TOLEDO Automated Melting & Dropping Point Analysis How to Clean the Dropping Point Furnaceon How to Clean the Dropping Point Furnaceon Thermal treatment under pure oxygen atmosphere or ambient air is recommended, if the furnace of a DP70 or DP90 Excellence dropping point system is contaminated with decomposition products that originated from thermal decomposition of the samples such as lubricant grease during dropping point tests However, best practice is to avoid having to clean the furnace This is achieved by preparing samples carefully and making sure that the sample carrier, cups and cup lids are free of residue Nevertheless, the area around the sample carrier can still become sticky over time and request removal of such decomposed materials 4.1 Figure 10: Cross section view of a DP70 The furnace and the camera glass that may be contaminated with decomposition products When is furnace cleaning due? • The video image has darkened and may require adjustment of the brightness factor • During startup of the instrument the furnace position may not be accurately detected anymore Then a respective error message will appear to alert the user and to indicate that default parameters for furnace position detection are being used 4.2 Cleaning procedure Please adhere to the general lab safety measures and instrument safety as described in the operating instructions If you are unsure about the cleaning procedure, please contact METTLER TOLEDO first for service advice Instead of disassembling the furnace followed by thorough manual cleaning with solvents or abrasive materials, a thermal treatment is recommended Apply pure oxygen gas and heat the furnace to 400 °C until clean At this temperature the decomposed materials are oxidized to carbon dioxide Usually a one hour treatment is sufficient to clean the contaminated parts If necessary the procedure shall be repeated METTLER TOLEDO Automated Melting & Dropping Point Analysis 11 How to Clean the Dropping Point Furnaceon The instrument shall be placed preferentially in a hood or alternatively in a well ventilated place A slight stream of oxygen (approximately 20 mL/min) from a pressurized gas bomb applied during the whole heating process is sufficient The oxygen stream shall be directed directly into the furnace Let the instrument cool off to room temperature Now, the furnace is clean and ready for the next analyses 4.3 DP cleaning method We recommend to program the following method Figure 11: Setup of dropping point instrument and oxygen gas supply Temperature segments Start temperature: 394 °C Waiting time: 1000 s Heating rate: 0.1 C/min End temperature: 400 °C Evaluation Operation mode: Dropping point Set manually: No Temperature correction: No Brightness: 50% Result round-off: 0.1 Calibration substance: No Termination and end behavior Stop at event: No End behavior: Remove temperature Temperature: 50 °C In order to save the furnace, a lower end temperature of 350 - 380 °C can be applied as long as the decomposed materials are still oxidized Set the start temperature °C lower than the selected end temperature 12 METTLER TOLEDO Automated Melting & Dropping Point Analysis Performance Verification with MP VPac™ Performance Verification with MP VPac™ 5.1 Ready-to-use Kit of Traceable Reference Substances Performance verification by temperature calibration is the recommended workflow to ensure faultless routine operation of a melting point instrument and to secure result reliability The MP VPac provides different certified reference substances in prefilled, sealed capillaries for a simple method of verifying instrument accuracy over the temperature range 40 to 230 °C No sample grinding and time-consuming manual upfront filling of melting point capillaries is required Just take the pre-filled capillaries and insert them into the MP instrument furnace, as in a normal method The preprogrammed performance verification (->calibration method) can be started directly without any modification Each of the three reference substances included in the MP VPac comes with a certificate that states the certified temperature value including measurement uncertainty Figure 12: MP VPacTM contents 5.2 Do-it-yourself Service This is a cost-effective and do-it-yourself service that can be performed on Melting Point Excellence instruments It allows you to: • Have confidence in the accuracy of your results • Control the performance of the melting point system • Receive an unbiased and traceable analysis verification Performance verification is recommended: • After setting up an instrument • In relation with operational qualification of an instrument • For monthly periodic check of the instrument 5.3 Reference Substances The MP VPac™ contains the following melting point reference substances, each in 50 sealed standard METTLER TOLEDO melting point capillaries • Phenyl salicylate: Thermodynamic melting point: 41.8 ±0.2 °C Pharmacopeia melting point (1 °C/min heating rate): 43.8 ±0.2 °C • Benzoic acid: Thermodynamic melting point: 122.4 ± 0.2 °C Pharmacopeia melting point (1 °C/min heating rate): 124.4 ±0.2 °C • Saccharin: Thermodynamic melting point: 228.3 ±0.3 °C Pharmacopeia melting point (1 °C/min heating rate): 230.3 ±0.3 °C METTLER TOLEDO Automated Melting & Dropping Point Analysis 13 More Information More Information Find more information to the following topics: Presentation of all instruments of the MP and DP Excellence instrument line, including technical information (downloadable product brochures) www.mt.com/MPDP Comprehensive product movies showing the operation of the MP and DP Excellence line instruments www.mt.com/one-click-melting www.mt.com/one-click-dropping Good Melting and Dropping Point Practice GMDP™: Service product offering supporting the whole life cycle of the MP and DP Excellence instruments, including risk check, downloadable data sheets and application literature www.mt.com/GMDP Detailed information about the LabX PC Software for the MP 70 and MP90 Excellence instruments www.mt.com/LabXMP Useful accessories which support secure and efficient sample preparation for melting , dropping and softening point determination www.mt.com/MPDPaccessories MPVPac™ performance verification: a unique self service for MP Excellence instrument performance verification based on pre-filled, certified reference substances www.mt.com/MPVPac Comprehensive on-demand webinars that introduce automatic melting, dropping and softening point determination A lot of useful application tips & hints and a concluding knowledge-testing quiz are included Go to • Good Melting Point Practice • Good Dropping Point Practice 14 METTLER TOLEDO www.mt.com/webinar-analytical Automated Melting & Dropping Point Analysis 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 With this information, Good Measuring Practices provide straight forward ­recommendations for selecting, installing, calibrating and operating laboratory equipment and devices • Guaranteed quality • Compliance with regulations, secure audits • Increased productivity, reduced costs • Professional qualification and training Routine Operation Calibration / Qualification Evaluation Good Measuring Practices Learn more about Good Measuring Practices program www.mt.com/gp Selection Installation / Training Good Melting and Dropping Point Practice™ Reliable thermal values – optimized by GMDP™ www.mt.com/GMDP www.mt.com For more information Mettler-Toledo Laboratory Division CH-8606 Greifensee, Switzerland Tel +41 44 944 22 11 Fax +41 44 944 30 60 Subject to technical changes © 05/2015 Mettler-Toledo AG Global MarCom Switzerland / MC [...]... during the whole heating process is sufficient The oxygen stream shall be directed directly into the furnace Let the instrument cool off to room temperature Now, the furnace is clean and ready for the next analyses 4.3 DP cleaning method We recommend to program the following method Figure 11: Setup of dropping point instrument and oxygen gas supply Temperature segments Start temperature: 394 °C Waiting... temperature 6 °C lower than the selected end temperature 12 METTLER TOLEDO Automated Melting & Dropping Point Analysis Performance Verification with MP VPac™ 5 Performance Verification with MP VPac™ 5.1 Ready-to-use Kit of Traceable Reference Substances Performance verification by temperature calibration is the recommended workflow to ensure faultless routine operation of a melting point instrument and... verification Performance verification is recommended: • After setting up an instrument • In relation with operational qualification of an instrument • For monthly periodic check of the instrument 5.3 Reference Substances The MP VPac™ contains the following melting point reference substances, each in 50 sealed standard METTLER TOLEDO melting point capillaries • Phenyl salicylate: Thermodynamic melting point:... More Information Find more information to the following topics: Presentation of all instruments of the MP and DP Excellence instrument line, including technical information (downloadable product brochures) www.mt.com /MPDP Comprehensive product movies showing the operation of the MP and DP Excellence line instruments www.mt.com/one-click-melting www.mt.com/one-click-dropping Good Melting and Dropping... the MP and DP Excellence instruments, including risk check, downloadable data sheets and application literature www.mt.com/GMDP Detailed information about the LabX PC Software for the MP 70 and MP90 Excellence instruments www.mt.com/LabXMP Useful accessories which support secure and efficient sample preparation for melting , dropping and softening point determination www.mt.com/MPDPaccessories MPVPac™... When is furnace cleaning due? • The video image has darkened and may require adjustment of the brightness factor • During startup of the instrument the furnace position may not be accurately detected anymore Then a respective error message will appear to alert the user and to indicate that default parameters for furnace position detection are being used 4.2 Cleaning procedure Please adhere to the general... carbon dioxide Usually a one hour treatment is sufficient to clean the contaminated parts If necessary the procedure shall be repeated METTLER TOLEDO Automated Melting & Dropping Point Analysis 11 How to Clean the Dropping Point Furnaceon The instrument shall be placed preferentially in a hood or alternatively in a well ventilated place A slight stream of oxygen (approximately 20 mL/min) from a pressurized... modification Each of the three reference substances included in the MP VPac comes with a certificate that states the certified temperature value including measurement uncertainty Figure 12: MP VPacTM contents 5.2 Do-it-yourself Service This is a cost-effective and do-it-yourself service that can be performed on Melting Point Excellence instruments It allows you to: • Have confidence in the accuracy of your... Waiting time: 1000 s Heating rate: 0.1 C/min End temperature: 400 °C Evaluation Operation mode: Dropping point Set manually: No Temperature correction: No Brightness: 50% Result round-off: 0.1 Calibration substance: No Termination and end behavior Stop at event: No End behavior: Remove temperature Temperature: 50 °C In order to save the furnace, a lower end temperature of 350 - 380 °C can be applied...How to Clean the Dropping Point Furnaceon 4 How to Clean the Dropping Point Furnaceon Thermal treatment under pure oxygen atmosphere or ambient air is recommended, if the furnace of a DP70 or DP90 Excellence dropping point system is contaminated with decomposition products that originated from thermal decomposition of the samples such as lubricant grease ... Sulfanilamide 164 .0– 165 .7 164 .1– 165 .0 0.9 TA: 0.23 TC: 0.05 Sulfapyridine 190.0–192.0 1.5 191.1–191.9 0.9 TA: 0.05 TC: 0.04 Caffeine 235 .6 237.5 235 .6 2 36. 1 0.5 TA: 0.07 TC: 0.07 Table 2: USP references... Measured MR [°C] Repeatability [°C] Azobenzene 69 .0 (± 0.4) 69 .0 TC: 0.22 Vanillin 83.2 (± 0 .6) 83.3 TC: 0.17 Acetanilide 1 16. 0 (± 0.3) 1 16. 1 TC: 0.09 Phenacetin 1 36. 0 (± 0.3) 135.7 TC: 0.15 Sulfapyridine... reference substance, the instrument needs to be adjusted ("adjustment") METTLER TOLEDO reference substances such as Figure 3: METTLER TOLEDO reference substances benzophenone, vanillin, benzoic