Metrohm Vision User Manual

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NIRS

Vision – Diagnostics

Manual

8.105.8013EN

Metrohm AG CH-9100 Herisau Switzerland

Phone +41 71 353 85 85 Fax +41 71 353 89 01 info@Metrohm.com www.Metrohm.com

NIRS

Vision – Diagnostics

Manual

8.105.8013EN

2014-06-20 / fpe

Teachware

Metrohm AG CH-9100 Herisau

teachware@Metrohm.com

This documentation is protected by copyright. All rights reserved.

Although all the information given in this documentation has been checked with great care, errors cannot be entirely excluded. Should you notice any mistakes please send us your comments using the address given above.

Table of contents

1

Overview

........................................................................................................................

5

 

1.1

Vision Diagnostics Screen Display .................................................................

9

2

Performance .........................................................................................................Test

12

 

2.1 ....................................................................................................

Overview

12

 

2.2 ...................................................................................................

Noise Test

14

 

2.3 ........................................

Bandwidth: Wavelength Accuracy and Precision

16

 

2.4 ................................................................................

Model 5000 and 6500

16

 

2.5 .......................

Wavelength Accuracy / Precision Measurement on the XDS

17

 

2.6 ............................................................................

Operational Qualification

18

 

2.7 ..............................................................................

Performance Test Timer

19

3

Wavelength ..............................................................................................Certification

20

 

3.1 .....................................................................

Run Wavelength Certification

20

 

3.2 ........................................

Setting up a User - Defined Wavelength Standard

23

4

Reference ...........................................................................................Standardization

24

 

4.1 ...................................................................

Creating a Reference Standard

25

 

4.2 ....................................................................

Loading a Reference Standard

28

 

4.3 ...........................................................................

Reset Reference Standard

28

5

Create Blank ...............................................................................................Correction

29

6

Window Correction ......................................................................................................

31

7

Low-Flux ...............................................................................................................Test

32

8

Instrument .....................................................................................................Self-Test

34

9

Wavelength .............................................................................................Linearization

35

 

9.1 ..................................

Wavelength Linearization on Model 5000 and 6500

35

 

9.2 ...........................................

Wavelength Linearization on XDS Instruments

36

 

9.3 .............

Special Note on Wavelength Linearization of Process Instruments

37

10

.................................................................................................

Gain Adjust

38

 

10.1 .....................................................................................................

Autogain

38

 

10.2 ...............................................................................................

Manual Gain

39

11

........................................................................................

Photometric Test

40

12

....................................................................................................

IPV Setup

44

13

...................................................................................

Diagnostic Database

46

 

13.1 ..........................................................................

View Diagnostic Database

46

 

13.2 ...................................................

Backup and Restore Diagnostic Database

46

 

13.3 ...................................................

Archive Diagnostic Database Information

47

 

13.4 ..................................

Export and Import Diagnostic Database Information

48

 

13.5 ......................................................................................

Diagnostics Timers

49

 

13.6 ........................................................................................

Maintenance Log

51

 

13.7 ................................................................................................

Show Status

52

14

...........................................................................

Instrument Configuration

53

15

...........................................

Instrument Calibration (XDS instruments only)

54

16

....................................................................................................

USP Tests

56

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16.1

Full USP Test ..............................................................................................

56

16.2

USP Noise ..................................................................................................

57

16.3

Usp Low-Flux Noise Test ............................................................................

57

16.4

Usp Wavelength Accuracy..........................................................................

58

USP Photometric Linearity Test ...................................................................................

59

16.5

Photometric Linearity Setup.......................................................................

61

16.6

Show USP Test Results...............................................................................

61

17

Troubleshooting Tips .................................................................................

62

17.1

Instrument Error: Run Wavelength Linearization........................................

62

17.2

Weak Signal ...............................................................................................

62

17.3

Increasing Noise.........................................................................................

63

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1 Overview

Vision provides a complete set of diagnostics functions to test whether the Metrohm instrument performs according to the manufacturer’s specifications. Instrument performance tests verify the reliability of NIRSystems spectrophotometers, which insures the linearity, limits of detection, and precision of NIR methods.

The Vision software drives all Metrohm spectrophotometers. There are differences in the performance and diagnostic testing associated with the instruments. For the Model 5000 and 6500 instruments, please refer to the Instrument Performance Test Guide for further explanation on performance tests. For the XDS instruments, there are additional set-up and evaluation diagnostics, with slight differences for the various analyzers. Proper application of these tests is recommended to ensure instrument matching and the seamless transfer of calibration methods developed on the XDS. There are specific requirements for process instruments as well. Refer to the instrument manual for your particular instrument. For tests that require the use of external standards, be careful that the correct standards are used depending on your instrument type. Please be sure to follow the correct section in this manual for your particular instrument type.

More detailed information about XDS Analyzers can be found in the installation and user manuals provided with the analyzer:

8.921.8001EN Manual NIRS XDS RapidContent and RCA Solids Analyzer

8.921.8004EN Manual NIRS XDS SmartProbe Analyzer

8.921.8005EN Manual NIRS XDS RapidLiquid Analyzer

8.921.8006EN Manual NIRS XDS Interactance OptiProbe Analyzer

8.928.8001EN Manual NIRS XDS Process Analyzer – MicroBundle

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Instrument model

Module

Standards

Numbering

 

 

 

 

5000 or 6500

RCA, DCA, Smart Probe,

AP-0200 Reflectance

RSS1xxxx

 

Sample Transport

Standards

 

 

(Reflectance), etc.

 

 

 

 

 

 

5000 or 6500

Liquid Analyzer, Sample

AP-0220 Transmission

TSS3xxxx

 

Transport (Transmission.)

Standards

 

 

 

 

 

5000 or 6500

InTact

AP-0230 Single Tablet

TSS2xxxx

 

 

Standards

 

 

 

 

 

5000 or 6500

MultiTab

AP-0240 Multi Tablet

TSS2xxxx

 

 

Standards

 

 

 

 

 

XDS

RCA, Rapid Solids Module,

XC-1010 Reflectance

RSS1xxxx

 

Smart Probe, OptiProbe

Standards

 

 

(reflectance)

 

 

 

 

 

 

XDS

Rapid Liquid Analyzer

XC-1310 Transmission

TSS3xxxx

 

 

standards

 

 

 

 

 

NIST traceable standards for use on the Metrohm NIR spectrophotometers

6 ▪▪▪▪▪▪▪

Vision SP includes enhanced Diagnostics, designed specifically to meet the needs of users in regulated industries who must maintain complete instrument records of performance over time, including conformance to photometric and\ wavelength standards. Among the features are the following:

Diagnostic Database structure to support multiple instruments, multiple sampling configurations

Built-in table with acceptance specifications for all current, standard Metrohm NIRSystems instrument and sampling modules, applied by instrument configuration

Recallable test results, with control charts to show performance changes over time

Control charts offer both calculated control limits and manufacturer’s tolerances

A unique screen display to show data in various formats, permitting enlargement of each area for better interpretation

Test timer supports all available tests, prompts operator when tests are due

Instrument Self-Test (similar to NSAS Self-Test)

Photometric Certification tests for supported reflectance and transmission standards

Wavelength Certification for supported (and user-defined) wavelength standards

Instrument Performance Verification (IPV) for regular user tests of photometric performance

Low-Flux Test in support of pharmaceutical requirements

Reference Standardization for users of reflectance instruments

Instrument maintenance log with comment fields

Blank Correction (for XDS transmission measurements)

Instrument Calibration (for ensuring calibration transfer between XDS instruments)

Window Correction (For XDS process systems)

USP tests including Noise, Low-Flux Noise, Wavelength Accuracy and the Photometric Linearity Test – with results displayed according to the USP chapter <1119>.

▪▪▪▪▪▪▪ 7

The tests in this manual are listed in the order in which they appear in the Vision software drop down menus. More information on the order of running tests can be found in the Installation and user manuals for the particular instrument being used.

When an instrument is first connected to Vision, Vision will determine whether there is a diagnostic record for this instrument configuration. In order to establish the correct instrument record in the Diagnostic Database, choose the option to create the diagnostic record when the initial screen appears telling that a Diagnostic Record does not exist for this instrument.

Saying “yes” will not initialize the testing, but will enter the instrument configuration information in the Diagnostic Database.

An instrument configuration is defined as a given monochromator and it assembled sampling components, including fiber-optics, if used. Where fiber-optics are used, the sampling tip type, fiber material and fiber length all constitute part of the monochromator configuration.

For most users with a single instrument, the configuration may never change, and is thus not an overriding issue in diagnostics. Other users may operate several instruments from one computer, or may change sampling modules based upon the sample characteristics. Diagnostic test results must be maintained separately for each configuration, to assure use of correct tolerances, and for correct information in control charts.

8 ▪▪▪▪▪▪▪

Metrohm Vision User Manual

If the instrument configuration is not recognized upon connection, Vision prompts for full instrument configuration information, including serial numbers of the monochromator and modules. A typical screen for a simple configuration is shown.

For instruments with fiber-optic sampling devices, the tip, material, and fiber length are required. For multiplexed process systems, enter this information for each channel.

Vision builds a database of diagnostic information for the instrument. It is vital to enter correct information, to assure application of correct tolerances for tests and for accurate tracking of test results.

Confirmation of Instrument configuration

Tools for export, import and archiving of information in case of computer upgrades, changes, or instrument moves, are explained under Diagnostic Database.

1.1 Vision Diagnostics Screen Display

Vision Diagnostics use a split-screen display to provide as much information as possible to the user. This is a screen displayed during the Performance Test; other tests use the same display format. Because each part of the screen may be used at different points during the test, all are displayed in small size, and can easily be enlarged for better viewing. Each part of the screen is discussed in the section following.

Vision Diagnostics Screen Display

▪▪▪▪▪▪▪ 9

The user may size the boxes manually using the mouse to move the partitions left, right, up or down. The configuration box, spectrum box, and control chart boxes are all a double right-click to enlarge or restore. After enlargement, double-click is repeated to return to the original display mode.

The instrument selection tree lists all instruments for which information is stored in the database.

Click on the “+” sign beside each node to see all items underneath. Each instrument lists all stored configurations, tests, along with the date and time of each test.

The Hint box tells how to zoom each of the four boxes, along with other useful suggestions.

The hint box is useful throughout Vision, and suggests steps to the user to help navigate Vision most efficiently.

The upper middle box lists the full instrument configuration. The box shown is for a process system, which includes fiber-optic probes.

With process systems, the “Sampling Module Type” is integral to the instrument, and carries the same serial number as the instrument.

Comments can be added for individual test results by clicking on the “Add Comment” combo box.

The upper right box shows spectra where applicable. In this case, noise spectra for a tested instrument are displayed.

10 ▪▪▪▪▪▪▪

Other information displayed is the reference scan, or the polystyrene/didymium spectra used for wavelength linearization.

A left-click on the spectrum gives a cursor which gives wavelength and absorbance information for a selected spectrum, as throughout Vision. The selected spectrum is identified by a color bar above the wavelength and absorbance.

When this window is active the user may click on the camera icon to copy the spectral image to the clipboard. The user may click on the printer icon to print spectra.

The lower left quadrant shows control charts, when enough data is stored for a given instrument configuration to plot control charts.

The top row of tabs is for selection of test (RMS noise is shown). Other choices are Peak-to-Peak, Bias, Bandwidth, and the Wavelength Linearization peaks.

The bottom tabs select between tolerances or control limits. Control limits are calculated on one specific instrument and give an excellent insight into any changes that may occur over time. Trends may be noted and acted upon before the parameter has gone outside of tolerance.

The lower right box shows tabular data. Click on the tabs at the bottom to see each view. The options are Noise, Summary, Wavelength, and OpQual (Operational Qualification). The OpQual tabs provide a summary of the actual instrument performance versus specification values.

A double right click on the table takes the user to Formula One Worksheet mode, which permits easy cut-and-paste export of results to other Windows™-based programs. When finished with Formula One, click on the “X” to close.

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2 Performance Test

2.1 Overview

Performance Test is a comprehensive test of instrumental performance, and is the final assurance that the instrument is ready to run samples. The key items verified during this test are:

Instrument Noise in several wavelength regions depending on the instrument type and configuration

Internal Wavelength Performance (wavelength positions on non-traceable, internal reference materials)

Internal Wavelength Precision (Repeatability)

NIR Gain

Visible Gain (where applicable)

Select Performance Test from the Diagnostics menu. Click on Run Performance Test. The test will commence immediately.

Performance Test takes approximately 15-25 minutes to run depending upon settings, instrument status and instrument type.

The test co-averages the results of 32 scans, irrespective of DCM settings for the number of scans. This assures correct application of acceptance specifications and consistent comparison of test results to initial factory test results.

The samples per test are set to a default of 10, but this can be changed under Performance Tests, Configure Test Parameters. Use the default settings unless there is a compelling reason to change them.

All diagnostic test results are stored in the Diagnostic Database, regardless of which project the user is logged into while performing the tests. The user may store results in Excel format using the drop-down menu shown. Test results in the Diagnostic Database can be recalled at a later time.

12 ▪▪▪▪▪▪▪

As the test runs, a screen like that shown to the left is displayed. When finished, a message box is displayed to indicate test completion and status.

At the end of the Performance Test, all measured values are compared with acceptance criteria stored in Vision. If all results meet acceptance criteria, the test is successful and this dialog box is displayed.

Before clicking “Close All Reports”, the user is directed to the tabular display in the lower right quadrant.

To enlarge the tabular display of results, place the cursor over the tabular display in the lower right quadrant and double-click twice. Now click on the OpQual tab, near the bottom of the screen to see a summary of noise test results.

The OpQual tab brings up the display shown. This shows results of the Noise Test for each of the up to four wavelength regions. The results are shown along with the specification values and a column to show if the test results are valid.

For each wavelength region, results are given for:

Peak-to-Peak Noise (P-P)

Root-Mean-Square Noise (RMS)

Bias (A measure of baseline energy changes)

Each of these parameters is described in more detail in the next section and in the Instrument Performance Test Guide supplied with the Metrohm instrument. If the test is reported as “Passed” the user may proceed with sample analysis.

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A note on Wavelength Linearization:

Sometimes when initiating Performance Test, Vision will report “Instrument Error: Run Wavelength Linearization”. The error report is posted near the end of the first set of 32 co-averaged scans, as Vision processes the data. This error occurs when an instrument configuration has been changed, the lamp is not on, the reference is not in the correct position, or due to a beam blockage. A troubleshooting table is provided at the end of Diagnostics to assist you in solving this issue.

2.2 Noise Test

The tabular output of the instrument Noise portion of Performance Test provides a wealth of information about the instrument. Instrument noise should appear as random spectral variability. Structure in the noise spectrum or high noise is often caused by changes in environment but also may be indicative of instrument problems. The Noise Test is the most sensitive diagnostic test used to determine instrument performance. The display provides information about noise and amplifier gain.

Instrument Noise (Displayed at lower right quadarant during Performance Test)

Vision breaks each instrument test up into segments (wavelength regions), based upon the instrument configuration. Acceptance specifications are applied to each segment. Segments can be adjusted by the user under Tests Params (under Data Collection Method) prior to acquisition of any spectra. Unless there is a reason to change segments, the user is encouraged to use the defaults.

Laboratory instruments generally use a ceramic reference in reflectance, or air in transmission. Process instruments offer the option of reference vs. reference, sample vs. sample, or sample vs. reference. Each result column in the noise test is explained:

SCAN#

Identifies which of the 10 sets of sample scans is being reported. A sample scan is defined as 32 sets of co-averaged reference vs. reference scans for a laboratory instrument.

14 ▪▪▪▪▪▪▪

EOC

End of convert. Communications failures during the instrument scan and with the computer are reported here. This number should be zero, and if not the source of communication errors should be investigated. Occasionally, EOC failures are due to random electrical noise or unexplained disturbance, and if not frequently repeated they are not considered a problem.

P-P

Peak-to-Peak noise is the difference between the largest and smallest value in the noise spectrum. (There may be a round-off error of .001 due to the mathematical algorithm.) The unit of measure is milliabsorbance units, or one-thousandth of one absorbance unit. For example, .139 equals 0.000139 absorbance units. The number may also be expresses verbally as microabsorbance units, or “139”. Peak-to-peak noise may be thought of as the greatest variation from one scan to the next scan of the noise spectrum across all measured wavelengths.

Minimum

This is the highest intensity negative peak height, in milliabsorbance units, of the noise spectrum. The wavelength where the minimum occurs is reported in the next column.

Wavelength

The wavelength where the peak minimum occurred.

Maximum

This is the maximum peak height, in milliabsorbance units, of the noise spectrum. The wavelength where the maximum occurs is reported in the next column.

Wavelength

The wavelength where the peak maximum occurred.

Bias

The bias is the average absorbance value of all points in the noise spectrum. Immediately after the instrument is turned on, the bias is quite high, and as the instrument warms up, bias settles to near zero with slight random excursions above and below. In normal operation, fully warmed-up, the bias should run in a range of +/-0.100 milliabsorbance units.

RMS

The Root Mean Square of the noise across the full spectral region in milliabsorbance units is reported. Each sampling configuration has acceptance specifications programmed in Vision. These are applied automatically. As with peak-to-peak noise, RMS is commonly referred to in microabsorbance units. (One-millionth of an absorbance unit.) In this case, 20 microabsorbance units is equivalent to 0.020 milliabsorbance units.

Gain

The “gain factor” for Autogain amplifiers is shown. For full-range instruments the NIR gain is shown first, then the visible gain. Metrohm’ instruments use a system of gain optimization called “AutoGain,” which uses the first scan of each data collection to adjust the gain level for the best resolution of signal.

The detector picks a gain factor to optimize signal. The gain factor depends upon the sample absorbance, requiring no user adjustment. This can be helpful when troubleshooting. For example, if

▪▪▪▪▪▪▪ 15

the instrument reference is not in place, gain factors may climb to the maximum value, and may also explain why RMS noise and P-P are outside of bounds.

2.3 Bandwidth: Wavelength Accuracy and Precision

Bandwidth is measured during the Performance Test on non-XDS instruments and during the Wavelength Certification test for XDS instruments. Metrohm instrument contains internal wavelength reference materials, which are used as a means to maintain monochromator wavelength measurement. These internal wavelength materials are protected and are moved by software command, transparent to the user. When Performance Test is run, the relative wavelength positions and repeatability of these wavelength materials are monitored and reported.

2.4 Model 5000 and 6500

The Bandwidth tab shows instrument bandwidth as well as wavelength accuracy and precision. In the NIR region, an internal polystyrene reference is analyzed by transmission measurement under software control. 10 replicate scans of the polystyrene standard are used to calculate these parameters.

The polystyrene absorbances which nominally occur at 806.10, 878.75, 1143.63, 1680.90 2166.72 and 2306.10 nm (Rev. C) are used to calculate wavelength accuracy and precision. A peak-finding algorithm is applied to the polystyrene spectra to determine the peak maxima. The average peak position obtained for 10 replicates determines the wavelength accuracy, and the standard deviation of those values determines measurement precision.

Delta is the difference between the accepted nominal values, and those reported by the instrument. The specification for reported vs. nominal is +/- 0.30 nm (+/- 0.50 for process instruments). Therefore, any peak found to be within 0.30 nm is considered acceptable. The software flags any peak outside the acceptance range and suggests that Wavelength Linearization be performed.

S/D is the standard deviation of the 10 replicates. This measures the stability of peak positions and

16 ▪▪▪▪▪▪▪

bandwidth. With respect to peak position, the specification on S/D is 0.015 nm or less, depending upon instrument model and type.

The instrument bandpass (bandwidth) is calculated using the ratio of the absorbance at the polystyrene peak at 2167 nm and the valley at approximately 2154 nm (after an offset correction.)

The S/D test is also run in the 400-1100 area of the spectrum on models 5500 and 6500. In this area, didymium/polystyrene is used for two of the peaks, at 806.10 and 878.85 nm. Bandwidth is not calculated in the 400-1100 nm area.

Process instruments (and certain laboratory instruments) cannot use the polystyrene peak at 2306.10 nm due to attenuation of the signal in the fiber-optics, or limitations in wavelength range. On such instruments the tests will not report values for the 2306.10 peak, and will perform wavelength tests on peaks within the wavelength response of the instrument.

Note: Wavelength positions are empirically determined, and have been set based upon the best measurements possible given the technology available. As instrumental or standardization breakthroughs lead to greater precision in setting nominal peak positions, Metrohm reserves the right to issue revised nominals.

2.5 Wavelength Accuracy / Precision Measurement on the XDS

The XDS instrument, like the model 5000 and 6500, uses an internal wavelength reference material. When Performance Test is run, the relative wavelength positions and repeatability of these wavelength materials are monitored and reported. The internal standard for the XDS is comprised of polystyrene, erbium oxide and samarium oxide and six peaks across the range from 500-2310nm are used to determine the internal wavelength performance of the instrument.

Note that these internal wavelength materials need not be precisely on the assigned nominals. These nominals are arbitrary. The internal wavelength materials are a method to assure stable readings on the external wavelength standard, measured at the sample plane during Instrument Calibration and Wavelength Certification.

▪▪▪▪▪▪▪ 17

2.6 Operational Qualification

A summary of noise results is available in the OpQual (Operational Qualification) screens. This screen gives specifications (for a given instrument configuration), the average of measured values, and an indication of whether the result is valid for that configuration. The measured values are the average result for 10 sets of scans, covering each wavelength region. Many users find this screen easier to interpret, and more concise, than the tabulated data for each set of scans.

Operational Qualification Summary Screen: Noise Test

The OpQual2 tab contains summary information on wavelength accuracy and precision. For Model 5000 and 6500 instruments it also contains information on the bandwidth, as shown:

Operational Qualification Summary Screen: Bandwidth, Wavelength Results

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