Pipette Test (Z Factor) Test Type

Pipette Test (Z Factor) Test Type
 

Set Up Test Type Packages Screen

The Set Up Test Type Packages screen (shown in Figure 1) is used to add, modify and if necessary delete test type packages from the database.  This screen is invoked by selecting the “Set Up Test Type Packages…” option on the File menu when the System Options and Defaults screen is open.

 

                                                                                                                                                                                                                                                                                                                    Figure 1

                                                                                                                                                                     

 

Adding New Test Types

To add a new test type to your database you must first copy the required library file “PipetteTestZFactor.bpl” into the folder labeled “bin” under the ProCalV5 directory (typically “C:\Program Files\Prime Technologies\ProCalV5\bin”) in Windows Explorer.  The “PipetteTestZFactor.bpl” file contains all the information necessary for the test type’s automatic and proper setup in ProCal.  Once the file has been copied into the correct folder you may launch the Set Up Test Type Packages screen.  Once the screen is open you may click the Add New Record button or select “New Record” from the screen’s File menu.  This invokes a browser screen titled Choose New Package File that automatically directs you to the “bin” folder in which all the “.bpl” files reside. Select the required file “PipetteTestZFactor.bpl” and click the Open button or double-click the file name.

 

Once the correct file has been selected you are returned to the new test type record which has already been set up for you.  In this instance you can save the record, making it available for application to all types of item master records in the system (i.e. instruments, loops, systems, test instruments, in addition to any PM records that may require a calibration).  Once a test type has been saved to the database, as long as it is marked as “Active”, it is  available for selection on the Test Type field’s drop-down list on the Calibration Points tab in all screens where that tab exists.   

 

Although you have no ability to change the test type’s calibration requirements, you do have the ability to make some customizations to it in terms of field label changes and also giving users the ability to edit target setpoints and such when entering calibrations using that test type.  Please reference section 8 of the user manual for information on modifying test type packages once they have been imported into the database.

 

Distributing Test Types

Test Types only need to be installed in the System Option and Defaults screen once, but for all Client, Administrator, or Mobile Workstations, the “PipetteTestZFactor.bpl” file must be present in the “bin” directory one level down from the ProCalV5 installation directory.

 

Entering Item Records Using The Pipette Test (Z-Factor) Test Type Package

When creating a new master record that uses the Pipette Test (Z-Factor) Test Type, the test type must be applied to the record through the Calibration Points tab on the master record screen. Once a new group has been added to the record, click the Test Type drop-down list and select Pipette Test (Z-Factor) from the available test types, as shown in Figure 2:

 

                                                                                                                                                                     Figure 2 

 

 

Once the test type has been selected, the inputs change according to the settings defined by the library file.  This test type performs a conversion between weight and volume. A water density table is utilized for the conversion calculations. The water density table is shown in Attachment 1. This Pipette Test Type tests the accuracy at each reading and the Mean Volume, Accuracy Percentage, and Precision Percentage for each set of test volumes. 


 

The Calibration Points tab contains fields in which to enter calibration information for the instrument. 

Group Name, # of Cal Pts, In Res, In Low Range, In High Range, Precision CTL, Accuracy CTL, Accuracy PCTL, Precision PCTL. See Figure 2a below.

 

                                                                                                                                    Figure 2a

The Additional Test Type Inputs used in this test should be entered through the Group Options feature, which can be accessed by clicking the Show Group Options button on the right side of the screen. This interface is shown in Figure 3.  


 The Additional Test Type Inputs are as follows:

  • Balance Unit - Selected from a list of g, mg or ug.  Changing the unit affects the weightàvolume calculation via a unit multiplier applied to the z-factor.   
  • Default Readings per Test- The number of readings to take per test.  This is just a default and the actual number may be changed at the time of entering test data.  Can Edit is no because the actual # of readings are outputs associated with each test.
  • Nominal Volume- Nominal Volume of UUT See Table 1: Selection Criteria for Balances. See 5.7.1   Warm Up & Preparation in SOP A003700-V4.0 Pipettes.pdf
  • Nominal Volume Unit- Volumetric unit for Nominal Volume: selected from a list of Microliters (µL) or Milliliters (mL).  The full names of the units are spelt out in the input list, but the abbreviations are used on the calibration form and report. 
  • Require Evaporation Compensation - Select yes or no from a list.  If yes is selected then an Evaporation Compensation Calculation is always be required.  If no is selected then it still may optionally be performed and 0 is used for e bar if not.


 
 

The Pipette Test (Z-Factor) Test Type requires that there be at least three (3) Default Readings per Test Point in order to make the correct calculations

 

 

                                                                                                                                                                                                                                                                                                                                       Figure 3


 

 

Entering Calibration Records for Items That Use the Pipette Test (Z-Factor) Test Type

Once a calibration has been created for a master item record that uses the Pipette Test (Z-Factor) Test Type, the calibration data can be entered on the Test Results tab. The Calibration screen is shown in Figure 4 below. It should be noted that the required inputs must be entered on the master item record as detailed above.  

                                                                                                                                                                           

                                                                                                                                                            Figure 4

 

 

Data for the test points should be entered on the Test Results screen, which can be accessed by clicking the Enter Data button on the left side of the screen. This Test Setup interface is shown in Figure 4a.  

 

 

The Test Setup screen contains general information about the test not specific to any as found or as left readings.  It also has fields to capture setup data that is required to start the test and that has a place for the user to enter the following:

 

  • Balance Sensitivity - An appropriate list of sensitivities (displayed as decimals like 0.1, 0.01, etc) are available to select the value based on nominal volume.  The range is from the minimum specified for the nominal volume by the SOP and the max is 7 decimal places (0.0000001). 
  • Balance Unit - Selected from a list of g, mg or ug.   Changing the unit affects the weightàvolume calculation via a unit multiplier applied to the z-factor.
  • Balance Check Performed - Indicates that the balance check was done.  Calibration data cannot be entered until this is Yes.
  • Evaporation Compensation Check Performed - Indicates if the compensation for evaporation loss test is performed
  • PM Performed - Indicates if maintenance was done as part of the calibration.  If this is No, then none of the other PM related fields are displayed. If Yes, then the PM related fields are displayed and can be checked indicating they have been replaced: 
    1. Replace Seal.
    2. O-Ring
    3. Piston
    4. Shaft
    5. Tension Ring
    6. Repaired - indicates repairs were made
    7. Adjustments - indicates adjustments were made
  • Evaporation loss (e bar) - A single weight reading for the mean evaporation loss calculation. 

 

The form contains 3 buttons:

  • Close – Closes the input form.  If there have been modifications the user is prompted if they want to “Apply” before closing.
  • Apply – calculates and sets all outputs on the calibration record. (Note this does not save the data to the database.  Hitting the “Save” button on the calibration is required for this)
  • Recalculate - this recalculates the accuracy & precision values for each test and generate a new calibration code.  This only affects data on the screen and does not save to the database.

 

                                                                                                                                    Figure 4a


 

 

The Test Data screen contains all the fields for collecting test data and displaying calculated results.   There is a radio button to toggle between as found and as left data. This Test Setup interface is shown in Figure 4b.  

 

  • # Readings / Test- The number of readings to take per test.  This is just a default and the actual number may be changed at the time of entering test data.  Can Edit is no because the actual # of readings are outputs associated with each test
  • As Left same As Found – checkbox to indicate if As Left data is the same as As Found.   Checking this box copies all the As Found data to the As Left fields and disables it for entry, this includes the environmental conditions.
  • Temperature (Deg C) – Indicates environmental condition of the Room Temperature (20 – 25 Deg C)
  • Humidity - Indicates environmental condition of the relative humidity (35-75%) to minimize the evaporation rate and control the buildup of electrostatic charges
  • Pressure (mm Hg) - Indicates environmental condition of the barometric pressure
  • Weight – Mass reading

 

 

Calculations

 

 

 

Where    A = cubic expansion coefficient = 0.0001 cm3/°C

H = % relative humidity

ρa = density of air at temperature T (g/cm3) see

ρb = density of balance weights = 8.0 g/cm3 for stainless steel weights

ρw = density of test liquid at temperature T (g/cm3), see Table 2

P = barometric pressure (mm Hg)

T = temperature (°C)

Z = Z factor (µL/mg or cm3/g)

 

Mean Volume

 

       Vi =  (mi +  e) Z               [see ISO 8655-6 (3)]

 

                    

1         n                       1      n

       V   =       n         S  Vi     =      n       S (mi +  e) Z

                                    i =1                              i =1

 

 

 

 

Where     e = mean evaporation loss for ≤50µL pipettes (see section 5.7.2)

i = replica number

mi = individually measured mass

n = number of measurements

Vi = individually measured volume

V = mean volume

Z = Z factor 

 

 

 

Volumetric Precision

 

     E   =       V       Vs

 

Or in percentage as follows:

 

      E%  =     V       Vs  X 100

                              Vs

 

 

Volumetric Accuracy

 

 

1          n               

     SD     =        (n-1)      S (mi +  e) Z      Vi

                                    i =1                              

 

 

 

 

 

The weight à volume conversion for each test reading is:

Volume = (Weighti +) * Z-factor * Conversion 

Where Weighti   is read from the balance,  is the evaporation compensation (0 if test not performed), Z-Factor is calculated from the environmental conditions and the conversion factor is a value to ensure the Z-Factor units are either uL/mg  or ml/g.

 

Unit Conversion Table

Volume Unit

Weight Unit

Multiplier

Z-Factor

uL

g

1000

uL/mg  

uL

mg

1

uL/mg  

uL

ug

0.001

uL/mg  

mL

g

1

mL/g

mL

mg

0.001

mL/g

mL

ug

0.000001

mL/g

 

 

                                                                                                                                                                                                                                                                                                                                             Figure 4b

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 

 

Pass/Fail Criteria

As Found Passed: All As Found Accuracy % & Precision % values ≤ respective CTL values

 

As Left Passed: All As Left Accuracy % & Precision % values ≤ respective CTL values

 

Group Calibration Code

A = All As Found ≤ CTL & all As Left ≤ CTL

B = Any As Found ≥ CTL, all As Found ≤ PCTL & all As Left ≤ CTL

C = Any As Found ≥ PCTL & all As Left ≤ CTL

D = Incomplete As Found (e.g. broken UUT) or any As Left ≥ CTL

 

NOTE: The Calibration Code is set to D if any values are missing for a test.

ATTACHMENT 1

 

Table 3: DENSITY OF WATER5

(Values given are in grams per cubic centimeter)

 

 

°C    0.0          0.1         0.2         0.3         0.4          0.5          0.6          0.7         0.8         0.9

18 .998595 .998576 .998558 .998539 .998520 .998501 .998482 .998463 .998443 .998424

 

19 .998404 .998385 .998365 .998345 .998325 .998305 .998285 .998265 .998244 .998224

 

20 .998203 .998182 .998162 .998141 .998120 .998099 .998077 .998056 .998035 .998013

 

21 .997991 .997970 .997948 .997926 .997904 .997882 .997859 .997837 .997815 .997792

 

22 .997769 .997747 .997724 .997701 .997678 .997654 .997631 .997608 .997584 .997561

 

23 .997537 .997513 .997490 .997466 .997442 .997417 .997393 .997369 .997344 .997320

 

24 .997295 .997270 .997246 .997221 .997196 .997170 .997145 .997120 .997094 .997069

 

25 .997043 .997018 .996992 .996966 .996940 .996914 .996888 .996861 .996835 .996809

 

26 .996782 .996755 .996729 .996702 .996675 .996648 .996621 .996594 .996566 .996539

 

27 .996511 .996484 .996456 .996428 .996400 .996373 .996344 .996316 .996288 .996260

 

28 .996232 .996203 .996174 .996146 .996117 .996088 .996059 .996030 .996001 .995972

 

29 .995943 .995913 .995884 .995854 .995825 .995795 .995765 .995735 .995705 .995675

 

30 .995645 .995615 .995584 .995554 .995523 .995493 .995462 .995431 .995401 .995370

 
 
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