Calibrating Using the Platinum™ Functions

DSC Q2000, Q200, and Q20 Only

The DSC Q2000/Q200/Q20 are equipped with verification/calibration features accessed through the Platinum functions. These features provide the following:

•  Setting Up A Platinum Calibration Sequence

•  Scheduling a Calibration Sequence of verification/calibration experiments

•  Email and/or Windows Messaging of process with results

•  Calibration report

• Indium Tracking

Setting Up A Platinum Calibration Sequence

Platinum functions are designed for automatic conditioning and calibration of your DSC instrument.  If your DSC is equipped with an Autosampler, the calibration sequence can be set up to automatically execute and analyze the resulting data on demand or at a specified day and time.

Before you begin calibrating, follow these steps:

1. If you plan to run the Cell/Cooler Conditioning template, turn off the cooling accessory, if it is on.

2. Remove any samples from the cell and cover the cell.

3. Open the instrument control program for a DSC instrument. See Using the TA Instrument Explorer for instructions.

4. Verify that the correct cooler is specified on the Tools/Instrument Preferences/Cooler page.

5. Verify that the Heat Flow selection is specified on the Tools/Instrument Preferences/DSC page.

6. Check that your purge gas is connected and set to the desired flow rate. If you are using an RCS or LNCS, be sure a Base purge gas is also used.

7. If you plan to run the cell constant/temperature calibration &/or verification, then prepare approximately 1-5 mg of indium in a sample pan. Crimp the pan. Prepare a reference pan using the same pan type used for the sample. Crimp the pan.  If your instrument is equipped with an Autosampler, position the pans in the desired platform positions.

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Creating a New Calibration Run Sequence:

1. Select the Platinum button, , at the bottom left-hand side of the main instrument control window.

2. Click AutoCalibration from the Automatic Tasks list on the left side of the window. Two options will be displayed. Choose the Create New Sequence option.

• Use Existing Sequence: This option leaves the current sequence in place allowing you to customize it or use it as is. After selecting this option, use the Sequence Pane to customize the experiment.

• Create New Sequence:  Used to set up a new test with the Platinum functions. This option will replace the current sequence.

3. Select (check) the desired procedures from the list of Tasks to implement.  This list will vary based on DSC model as well as selected cooler and heat flow selection.  A description of the available items is listed below.

• Cell/Cooler Conditioning: When an instrument and/or cooling accessory is first installed, this procedure should be run to dry the DSC cell and cooler before you turn on the cooler and start running any experiments. During this test the flange temperature limits are raised.

• Baseline Conditioning: When an instrument is first installed, this procedure should be run to stabilize the system before you start running any experiments. During this test an empty cell is heated and cooled multiple times to stabilize the system.

• T1 Baseline Calibration: The baseline slope and offset calibration involves heating an empty cell through the entire temperature range expected in subsequent experiments.  The calibration program is used to calculate the slope and offset values needed to flatten the baseline and zero the heat flow signal. This calibration is used in the DSC Q20 and Q10, and when the selected heat flow is T1 for the DSC Q2000, Q1000, Q200, or Q100.

• Tzero Heat Only Calibration: "Heat only calibration" is used when you are interested measuring transitions or heat capacity while heating the sample.  This calibration involves two experiments. Ramp rates greater than or equal to 10°C/min are used.

• Tzero Heat and Cool Calibration: The "Heat and Cool calibration" is used when you are interested in both heating and cooling data when measuring transitions or heat capacity (this option takes longer to calibrate).

•  Enthalpy/Temperature: These calibrations are based on a run in which a standard metal (e.g., indium) is heated through its melting transition. The calculated heat of fusion is compared to the theoretical value. The enthalpy (cell constant) is the ratio between these two values. The recorded melting point of this standard is compared to the known melting point and the difference is calculated for temperature calibration

NOTE:  Tzero calibration is only used with the DSC Q2000/Q1000 and Q200/Q100 for Heat Flow T4 and T4P.

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4. Enter the requested method and sample parameters for each type of calibration requested. Click on the links below to display the recommendations for the parameters:

• Cell/Cooler Conditioning Parameters

  1. Conditioning Temperature:  The cell will be heated to this temperature and held isothermal to allow it to dry. The recommended temperature is 75°C.

  2. Hold Time:  This is the amount of time that the cell will be held at the conditioning temperature specified above. The recommended time is 120 minutes.

  3. Enable secondary purge:  When using the RCS or LNCS, it is recommended that a source of dry nitrogen gas be connected to the cooling gas port if the instrument is used in high humidity environments or when recovering from moisture contamination. When the Enable secondary purge checkbox is used, the secondary purge will supply additional dry gas into the RCS and LNCS housing when the AutoLid is opened or when the PCA is being used. This option should be left blank if there is not a secondary gas connected to the cooling gas port and/or the port is capped. See also:  Connecting the Cooling Gas Line.

• Baseline Conditioning Parameters

  1. Start and Final Temperatures:  The actual starting and final temperatures chosen for a specific experiment must be within the usable temperature of the DSC/cooling accessory combination that you are using. The RCS and LNCS can be used for baseline conditioning spanning subambient to elevated temperatures. The FACS can be used for baseline conditioning from 50 to 500°C. The Quench Cooler cannot be used for baseline conditioning. These temperatures should bracket the region where sample transitions are expected to occur and they should be far enough below or above the transitions to establish a stable baseline. When selecting the final temperature you need to consider the sample that will be analyzed and the scope of your experiment. For the DSC, the default initial temperature is 50°C and the default final temperature is 200°C.

  2. Heating Rate:  The acceptable range of ramp rates for conventional DSC is 0.01 to 100°C/minute.  This range depends on a number of variables, including the temperature range covered and the presence of a cooling accessory. Faster heating rates generally increase sensitivity particularly for thermal events such as the glass transition. They also obviously shorten the time of analysis. Slower rates generally provide better resolution (separation of closely spaced thermal events). The heating and cooling in cyclic experiments are usually the same (3 to 5°C/minute).

  3. Number of Cycles:  The number of cycles required to assess stability or reversible transitions, such as melting and recrystallization, varies based on material.  Several cycles (3 to 5) usually provide a good indication of stability or ensure that no changes occur in the events observed.

• T1 Baseline Calibration Parameters

  1. Start Temperature & Final Temperature: Lower and Upper Temperatures:  These temperatures should bracket the region where sample transitions are expected to occur.

  2. Heating Rate:  The acceptable range of ramp rates for conventional DSC is 0.01 to 100°C/minute.  This range depends on a number of variables, including the temperature range covered and the presence of a cooling accessory. Faster heating rates generally increase sensitivity particularly for thermal events such as the glass transition. They also obviously shorten the time of analysis. Slower rates generally provide better resolution (separation of closely spaced thermal events). The heating and cooling in cyclic experiments are usually the same (3 to 5°C/minute).

  3. Calibration Analysis Limits: Enter the desired limits used when analyzing the data. The lower analysis limit should be positioned in from the lower experiment limit to allow for heating rate stabilization.

   

• Tzero Heat Only Calibration Parameters

  Enter the Method Parameters:

  1. Lower Temperature & Upper Temperature: Calibration must be performed using the same atmosphere and cooling accessory that will be used in subsequent experiments. Obviously, the lower and upper temperatures chosen for calibration must be within the operating range of the cooling accessory selected. In addition, the temperature range for calibration should be at least as broad as the range that will be used in subsequent experiments on your samples. Typical temperature ranges are: -180 to 400 °C for the LNCS, -90 to 550°C for the RCS90, -40 to 400°C for the RCS40, and 50 to 400 °C for the FACS. See also: Introducing the DSC Cooling Accessories.

  NOTE: The quench cooler cannot be used for Tzero calibration and experimentation.

  2. Ramp Rate: Calibration can be performed for heating only or for heating and cooling. The minimum ramp rate is 10°C/min in order to obtain reliable values for sensor thermal capacitance and resistance. Lower ramp rates provide weaker signals and less accuracy. For heat-only calibration, a ramp rate of 20°C/min is recommended. For heat and cool calibration, a rate of 10°C/min may be more practical since it may not be possible to maintain a higher cooling rate down to the lowest temperature of interest. Obviously, the type of cooling accessory determines the maximum cooling rate and minimum temperature for calibration.

   Define the Sample Parameters:

  1. Enter the Sample size and select the Pan # position (if applicable) of the sapphire calibration sample used in the second Tzero calibration experiment. If your DSC is equipped with an Autosampler, position the sample (without a pan) in the specific pan # position.

  2. Enter the Reference weight and select the Pan # position (if applicable) of the sapphire reference sample used in the second Tzero calibration experiment. If your DSC is equipped with an Autosampler, position the sample (without a pan) in the specific reference pan # position.

• Tzero Heat and Cool Calibration Parameters

  Enter the Method Parameters:

  1. Lower Temperature & Upper Temperature: Calibration must be performed using the same atmosphere and cooling accessory that will be used in subsequent experiments. Obviously, the lower and upper temperatures chosen for calibration must be within the operating range of the cooling accessory selected. In addition, the temperature range for calibration should be at least as broad as the range that will be used in subsequent experiments on your samples. Typical temperature ranges are: -180 to 400 °C for the LNCS, -90 to 550°C for the RCS90, -40 to 400°C for the RCS40, and 50 to 400 °C for the FACS. See also: Introducing the DSC Cooling Accessories.

  NOTE: The quench cooler cannot be used for Tzero calibration and experimentation.

  2. Ramp Rate: Calibration can be performed for heating only or for heating and cooling. The minimum ramp rate is 10°C/min in order to obtain reliable values for sensor thermal capacitance and resistance. Lower ramp rates provide weaker signals and less accuracy. For heat-only calibration, a ramp rate of 20°C/min is recommended. For heat and cool calibration, a rate of 10°C/min may be more practical since it may not be possible to maintain a higher cooling rate down to the lowest temperature of interest. Obviously, the type of cooling accessory determines the maximum cooling rate and minimum temperature for calibration.

   Enter the Sample Parameters:

  1. Enter the Sample size and select the Pan # position (if applicable) of the sapphire calibration sample used in the second Tzero calibration experiment. If your DSC is equipped with an Autosampler, position the sample (without a pan) in the specific pan # position.

  2. Enter the Reference weight and select the Pan # position (if applicable) of the sapphire reference sample used in the second Tzero calibration experiment. If your DSC is equipped with an Autosampler, position the sample (without a pan) in the specific reference pan # position.

• Enthalpy/Temperature Parameters

  Enter the Method Parameters

  1. Start and Final Temperature/Heating Rate: The method parameters (e.g., start temperature, final temperature, and heating rate) for calibration are automatically entered by the software based on the metal standard selected on the previous window. For example, if indium is the calibration standard selected and the heating rate is 10°C/min, the start and final temperatures are automatically set to 100 and 180°C respectively. To use these entries, check Use Current. Alternatively, you can enter your own values, if desired.

  2. Melt your standard prior to starting the experiment, if desired, by checking the Premelt option.

  Enter the Size and Pans information:

  1. Enter the Sample size and select the Pan # position (if applicable) of the calibration sample.  If your DSC is equipped with an autosampler, position the sample (without a pan) in the specific pan # position.

  2. Select the Reference Pan # position (if applicable) of the reference pan.  If your DSC is equipped with an Autosampler, position the sample (without a pan) in the specific pan # position.

  3. For T4P calibration, check Pan mass (T4P) then enter the weight of the Sample pan and Reference pan.

  Choose your Post Action Settings:

  3. If you want to determine if your current calibration is acceptable, choose the Verification (Verification is defined as a double-check of calibration, performed immediately after calibration, usually on the same sample to verify that the instrument has accepted the adjustments made during calibration.) radio button.

  4. If you wish to perform a full calibration, choose the Calibration (Calibration is defined as the adjustment of an instrument so that it provides correct theoretical value for a specific measurement on a well-characterized [certified] standard.) radio button.

  5. Check the Perform Calibration if Verification Fails box to automatically perform the calibration in the event the validation test does not fall within the acceptable validation criteria. Enter the Sample size of the calibration material. Select the Pan # by using the up/down arrows to choose the pan number containing your sample for the calibration experiment. Then enter the weight of the sample Pan.

  6. Check the Perform Verification after Calibration box to automatically verify the new calibration, if desired. Enter the Sample size of the calibration material. Select the Pan # by using the up/down arrows to choose the pan number containing your sample for the calibration experiment. Then enter the weight of the sample Pan.

  7. Enter the desired Verification Criteria for the temperature and enthalpy calibrations.

   

   

5. Select Apply to save the test setup and generate the calibration run sequence. The run sequence will be displayed in the Calibration Sequence.  

6. Edit the following Post Run Actions, if desired. The following default settings are associated with each calibration.

• Cell/Cooler Conditioning: None

• Baseline Conditioning: None

• T1 Baseline Calibration:  DO Baseline Calibration

• Tzero Heat Only Calibration: 1st experiment – None, 2nd experiment – If Tzero Calibration not successful, STOP sequence

• Tzero Heat and Cool Calibration:  1st experiment – None, 2nd experiment – If Tzero Calibration not successful, STOP sequence

• Enthalpy/Temperature: IF Indium Verification Successful STOP, IF Indium Calibration not successful STOP

If you wish to edit these Post Run Actions, click on the Post Run Action of the desired run # as displayed in the calibration run sequence list. Edit the option as desired.

If you wish to start a standard run sequence, after the calibration sequence has been successfully completed, select:  IF {calibration routine} successful, GO TO NEXT SEQUENCE for the last run in the calibration sequence.

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NOTE:  The current operator, extended comment and file naming scheme, specified within the calibration sequence, is used in the creation of this sequence. If you wish to edit any of these parameters, click on the run # and edit the associated parameter.

6. Place the samples in the sample pan and reference positions that were chosen above.

7. Select the Messaging page to specify the notification options desired.

8. Select Start to execute the sequence immediately or select the Schedule page to specify the time, day, and frequency of the calibration process.

9. Save this calibration sequence for future use, if desired. (Click on the Calibration button on the left-hand side. Click on the Save button, , at the top of the sequence pane.

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