Establishing Spectrophotometer Performance Tests: Standard Guide For

 

 

Designation: E1866  −  97 (Reapproved 2013)

Standard Guide for

Establishing Spectrophotometer Performance Tests1 This standard is issued under the fixed designation E1866; the number immediately following the designation indicates the year of  original origin al adoption or, in the case of revis revision, ion, the year of last revision. revision. A number in paren parenthese thesess indicates the year of last reappr reapproval. oval. A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.

1.2 This guide is not intended as a replacement for specific specific practices such as Practices E275 Practices E275,,  E925  E925,, E932  E932,,  E958  E958,,  E1421  E1421,, or E1683 that E1683  that exist for measuring performance of specific types of  spectrophotometers. Instead, this guide is intended to provide guidelines in how similar practices should be developed when specific practices do not exist for a particular spectrophotometer type, or when specific practices are not applicable due to

Ultraviolet and Visible Spectrophotometers E925 Practice E925  Practice for Monit Monitoring oring the Calibr Calibration ation of Ultrav UltravioletioletVisible Spectr Spectropho ophotometer tometerss whose Spectr Spectral al Bandw Bandwidth idth does not Exceed 2 nm E932 Practice E932  Practice for Describing and Measuring Performance of  Dispersive Infrared Spectrometers E958   Practice for Measuring Practical Spectral Bandwidth E958 of Ultraviolet-Visible Spectrophotometers E1421 Practice E1421  Practice for Describing and Measuring Performance of Fourier Transform Mid-Infrared (FT-MIR) Spectrometers: Level Zero and Level One Tests E1655   Prac E1655 Practice ticess for Inf Infrar rared ed Mul Multiva tivariat riatee Qua Quantit ntitativ ativee Analysis

sampling or safety concerns. guide can be used to develop performance perfo rmance tests for on-lineeThis on-lin process proce ss spectr spectropho ophotometer tometers. s.

E1683  Pra E1683  Practic cticee for Test esting ing the Per Perfor forman mance ce of Sca Scanni nning ng Raman Spectrometers

1. Sco Scope pe 1.1 This guide guide covers basic procedures procedures that can be used to develop develo p spectr spectropho ophotometer tometer performance performance tests. The guide is intended to be applicable to spectrophotometers operating in the ultraviolet, visible, near-infrared and mid-infrared regions.

1.3 This guide describes describes univariate univariate level zero and level one tests, and multivariate level A and level B tests which can be implemente imple mented d to measu measure re spec spectrop trophoto hotometer meter perf performa ormance. nce. These tests are designed to be used as rapid, routine checks of  spectrophotometer performance. They are designed to uncover malfunctions or other changes in instrument operation, but do not specifically diagnose or quantitatively assess the malfunction or change. The tests are not intended for the comparison of  spectrophotometers of different manufacture.

3. Terminology 3.1   Definitions—F —For or ter termin minolo ology gy rel relati ating ng to mo molec lecula ularr spectroscopic methods, refer to Terminology  E131  E131.. 3.2  Definitions of Terms Specific to This Standard: 3.2.1  action limit, n— the the limiting value from an instrument perfor per forman mance ce test test,, bey beyond ond whi which ch the spe spectro ctropho photom tometer eter is expected to produce potentially invalid results. 3.2.2   che check ck sa samp mple, le, n— a si sing ngle le pu pure re co comp mpou ound nd,, or a known, reproducible mixture of compounds whose spectrum is constant over time such that it can be used in a performance test.

1.4   This standar standard d doe doess not purport purport to add addre ress ss all of the safet sa fetyy co conc ncer erns ns,, if an anyy, as asso socia ciated ted wi with th it itss us use. e. It is th thee responsibility of the user of this standard to establish appro priate safety and health practices and determine the applica-

3.2.3   level A test, n— a pass/fail spectrophotometer performance test in which the spectrum of a check or test sample is compared against historical spectra of the same sample via a multivariate analysis.

bility of regulatory limitations prior to use.

2. Referenc Referenced ed Documents Documents 2.1   ASTM Standards:2 E131   Terminology Relating to Molecular Spectroscopy E131 E275 Practice E275  Practice for Describing and Measuring Performance of 

3.2.4   level B test, n— a pass/fail spectrophotometer performance test in which the spectrum of a check or test sample is analyz ana lyzed ed usi using ng a mul multiva tivaria riate te mod model, el, and the res results ults of the analysis are compared to historical results for prior analyses of  the same sample.

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This guide is under the jurisdiction of ASTM Committee   E13 E13   on Molecular Spectroscopy and Separation Science and is the direct responsibility of Subcommittee E13.03 mittee  E13.03 on  on Infrare Infrared d and Near Infrar Infrared ed Spect Spectrosco roscopy. py. Current Curre nt editio edition n approv approved ed Jan. 1, 2013. Published Published Janua January ry 2013. Originally Originally approved in 1997. Last previous edition approved in 2007 as E1866 – 97 (2007). DOI: 10.1520/E1866-97R13. 2 For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [email protected]. For  Annual Book of ASTM  Standards volume information, refer to the standard’s Document Summary page on

3.2.5  level one (1) test, n— a simple series of measurements designed design ed to pro provid videe qua quanti ntitati tative ve dat dataa on var variou iouss asp aspects ects of  spectrophotometer performance and information on which to base the diagnosis of problems. 3.2.6   level zero (0) test, n— a routine check of spectrophotometer tom eter performa performance nce,, whi which ch can be don donee in a few minutes, minutes,

the ASTM website.

designed to visually detect significant changes in instrument

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E1866 − 97 (2013)

performance and provide a database to determine instrument performance perfo rmance over time.

Spectral data used in performance tests should be date and time stamp st amped ed,, an and d th thee re resu sults lts of th thee tes tests ts sh shou ould ld be st stor ored ed in a historical database.

3.2.7   optical optical refe referen rence ce filter filter,, n— an opt optical ical filter or oth other er devi de vice ce wh whic ich h ca can n be in inse sert rted ed in into to th thee op optic tical al pa path th in th thee spectrophotometer or probe producing an absorption spectrum which is known to be constant over time such that it can be used in place of a check or test sample in a performance test.

6. Samples Used for Performance Testing Testing 6.1 The sample used for performan performance ce testing is chosen to be compatible with the spectrophotometer configuration, and to provide spectral features which are adequate for the tests being performed.

3.2.8   test test sam sample ple,, n— a pr proc oces esss or pr prod oduc uctt sa samp mple, le, or a mixture of process or product samples which has a constant spectrum for a finite time period and which can be used in a performance test. Test samples and their spectra are generally not reproducible in the long term.

6.1. 6. 1.1 1 Th Thee sa samp mple le us used ed fo forr pe perf rfor orma manc ncee te testi sting ng sh shou ould ld generally be in the same physical state (gas, liquid, or solid) as the samples samples to be ana analyze lyzed d dur during ing normal normal ope operat ration ion of the spectrophotometer. 6.1.2 6.1 .2 The sample used for performa performance nce testing testing sho should uld be physically and chemically compatible with the samples analyzed during normal operation. 6.1.3 The sample used for performanc performancee is chose chosen n such that its spectrum is similar to the spectra which will be collected during normal operation. 6.1.4 The sample used for performance performance testing should should have several significant absorbances (0.3 < absorbance < 1.0) across the spectral range used for normal operation of the spectrophotometer. 6.1.5 6.1 .5 In ord order er to ade adequa quately tely det determ ermine ine the pho photom tometr etric ic

4. Sign Significan ificance ce and Use 4.1 If ASTM ASTM Committee E13 has not specified an appropriappropriate test procedure for a specific type of spectrophotometer, or if th thee sa samp mple le sp speci ecifie fied d by a Co Comm mmitt ittee ee E1 E13 3 pr proc oced edur uree is incompatible with the intended spectrophotometer operation, then this guide can be used to develop practical performance tests. 4.1.1 For spectrophotom spectrophotometers eters which are equip equipped ped with permanent man ent or semi semi-pe -perma rmanen nentt sam sampli pling ng acce accesso ssorie ries, s, the test sampl sam plee sp speci ecifie fied d in a Co Comm mmitt ittee ee E1 E13 3 pr prac actic ticee may no nott be compat com patible ible with the spe spectr ctroph ophoto otomet meter er con configu figurat ration ion.. For example, for FT-MIR instruments equipped with transmittance or IRS flow cells, tests based on polystyrene films are impractical. In such cases, these guidelines suggest means by which the recommended test procedures can be modified so as to be performed on a compatible test material. 4 .1 . 2 Fo r sp e ct ct ro ro p h o t om ome te te rs rs u s ed ed in p r o c es es s measurements, the choice of test materials may be limited due to pro proces cesss con contami taminat nation ion and saf safety ety con consid sidera eratio tions. ns. The These se guidel gui deline iness sug sugges gestt mea means ns of dev develop eloping ing per perfor forman mance ce test testss based on materials which are compa compatible tible with the intend intended ed use of the spectrophotometer.

lineari linearity ty of the instrumen instrument, the peak absorba absorbance ncesi for at least abso ab sorp rpti tion on band ba nd of th thee t,sa samp mple le sh shou ould ld be simi milar lar to one and an d preferably slightly greater than the largest absorbance expected for samples measured during normal operation. 6.2   Check Samples— Check Check samples are generally used for conducting performance tests. Check samples are single pure compounds or mixtures of compounds of definite composition. 6.2.1 If mixtures mixtures are utilized as check samples, samples, they must be prepared prepa red in a repeatable manner and, if stored stored,, stored such that the mixture is stable over long periods of time. In preparing mixtu mix tures res,, co comp mpon onen ents ts sh shou ould ld be acc accur urate ately ly pi pipet petted ted or weig we ighe hed d at am ambi bien entt te temp mper erat atur ure. e. It is re reco comm mmen ende ded d th that at mixtures mixtur es be indep independent endently ly verifie verified d for composition composition prior to use. 6.2.2 6.2 .2 Whi While le mix mixtur tures es can be used as che check ck samples, samples, the their ir

4.2 Tests developed using these guidelines guidelines are intend intended ed to allow the user to compare the performance of a spectrophotometer on any given day with prior performance. The tests are intended to uncover malfunctions or other changes in instrumentt op men oper erati ation on,, bu butt th they ey ar aree no nott de desig signe ned d to di diag agno nose se or quantitatively assess the malfunction or change. The tests are not inte intende nded d for the com compar pariso ison n of spe spectr ctroph ophoto otomete meters rs of  different manufacture.

spectraa may be adv spectr advers ersely ely af affec fected ted by temp tempera eratur turee sen sensiti sitive ve interac int eractio tions ns tha thatt may man manife ifest st the themse mselve lvess by wav wavelen elength gth (frequency) and absorbance changes. 6.3   Test Test Samples— A tes testt sa samp mple le is a pr proc ocess ess or pr prod oduc uctt sample sam ple or a mix mixtur turee of pro proces cesss or pro produc ductt sam samples ples whose spectrum is expected to be constant for the time period it is used in performance testing. The test sample must be stored in bulk quantities in controlled conditions such that the material is stable over time. 6.3.1 Since test samples are often complex mixtures mixtures which cannot be synthetically reproduced, they can only be used for performance testing for limited time periods. If test samples are used for this purpose, collection of historical data on a new test sample sam ple sho should uld be init initiate iated d bef before ore pre previo vious us test sam samples ples are depleted. deplet ed. It is recommended recommended that new test sample sampless be analyz analyzed ed sequentially with old test samples at least 15 times before they are used to replace the old test sample. The 15 analyses must be per perfor formed med over a time period period tha thatt doe doess not exceed one month in duration.

5. Test Conditions 5.1 When conducting the performance tests, the spectrophotometer should be operated under the same conditions as will be in effect during its intended use. Sufficient warm-up time should be allowed before the commencement of any measurements. 5.1.1 If possible, the optical configuration configuration used for measuremeasurements of test and check samples should be identical to that used for normal opera operations. tions. If identic identical al optica opticall config configuratio urations ns are not possible, the user should recognize that the performance tests may not measure the performance of the entire instrument. 5.1.2 5.1 .2 Data col collect lection ion and com comput putatio ation n con condit dition ionss sho should uld gene ge nera rally lly be id iden entic tical al to th thos osee us used ed in no norm rmal al op oper erat atio ion. n. 2

 

 

E1866 − 97 (2013)

An optical reference filter is an optical 6.4   Optical Filters— An filter or other optical device located in the spectrophotometer or in a fiber optic sample probe which produces an absorption spectrum which is known to be constant over time. This filter may be automatically inserted into the optical path to allow instrument performance tests to be performed. 6.4.1 Optical filters are used principally principally with on-lin on-linee process spectrophotometers equipped with fiber optic probes when removal of the probe is inconvenient, precluding the use of 

conducted on a 100 % line spectrum. Alternatively conducted Alternatively,, photo photometmetric noise tests may be conducted on the spectrum of a check or test sample at regions where the spectrum is relatively flat and the sample absorbance is minimal (