example chemistry measurement uncertainty calculations v3 corrected 031312.xls

7/26/2019 Example Chemistry Measurement Uncertainty Calculations V3 corrected 031312.xls

1/18

Contributors to Uncertainty

Transportation/Storage/Handling:

shipping time, container and temperature NA / (FS)

lab storage time, conditions and temperature NA / (LCS, FS)

contamination in lab storage areas NA / LCS, FB

Laboratory Subsampling

sample nonhomogeneity D!

blending techni"ues D!

sample si#e D!

Sample Preparation:

$olumetric glass%are LCS, D!

dispensing de$ice LCS, D!

balance LCS, D!

temperature LCS, D!

sample e&traction LCS, D!

e&tractant bac'ground LCS, D!, B

Lab Environmental Conditions:

temperature $ariance LCS, D!

humidity $ariance LCS, D!

Analysts:

dierent analysts LCS, D!

analyst training le$el and e&perience LCS, D!

data interpretation by analyst LCS, D!

Measuring nstruments:

instrument stability LCS, D!

Common Contributors to M#representative list $ ma

#'C sample types in t"is list are typical o% t"ose uaddition

+epresentativeand Applicable

'C ,ata


2/18

carry o$er eects LCS, D!

day to day calibration dierences LCS

intererences LCS

preparation $ariances LCScalibration stoc' material uncertainty C*+-F-CA*

LCS reerence material uncertainty C*+-F-CA*

Test Procedure -ariations:

$ariation %ithin and bet%een reagent lots LCS

LCS

sample dependent modiications LCS

LCS

,ata Manipulation:sampling media/blan' correction LCS, B

instrument blan' correction LCS

accuracy o calculations LCS

area or air $olume sampled NA

.here

D! 0 Duplicate, resulting rom sub1sampling o a bul

FB 0 Field Blan'

B 0 ethod or atri& Blan'

NA 0 Not Applicable

Calibration Standards/+e%erenceMaterials:

e&traction or digestion times, temperatures,and conditions

desorption eiciencies %ithin and bet%eenlots or sorbents

FS 0 Field Spi'e 1 Not typically conducted unless part

is responsible or ield sampling3LCS 0 Laboratory Control Standard, matri& matchedbatch


3/18

Comments to Clari%y Contributor E%%ects

Sample composition, etc3

Stirring, sie$ing, grinding, etc3

Large enough to allo% ade"uate subsampling3

!ipettes, and other types o dispensers that are not Class A3

Balance error is oten insigniicant compared to other sources3

4ot plate or ashing temperatures3

Applies to LCS or D! i it goes throughthe entire sample preparation process3

Analyte or intererant is present in acids, sol$ents, etc3

+oom temp during bul' asbestos, gra$imetry, etc3 processes3

5ra$imetry in$ol$ing hydroscopic media, etc3

ust use inter1analyst instead o intra1analyst repeat data, %here applicable3

ust use inter1analyst instead o intra1analyst repeat data, %here applicable3

Baseline drit, repeatability o a$eraged readings, lab en$ironmental stability, etc3

asurement Uncertainty ! C"emical Analysesnot be all inclusive %or all types o% analyses&

tili(ed in AHA$LAP) LLC laboratories& Seel tabbed s"eets %or e*amples

.TE: T"is is not part o% analytical uncertainty) but must be considered by labsproviding sampling and 0"en providing guidance regarding sample pac1aging ands"ipping2 sually no impact i recommended shipping conditions and holding times inreerenced methods are maintained3 -mproper pac'ing materials, bul's shipped %/samples,etc3 may ad$ersely aect data3 Field blan's, ield spi'ed samples or duplicate ield samplesshipped %ith samples or included in method $alidation studies may relect these contributors3Field $ariability (FS/D!) is only considered %hen lab is responsible or sampling3

Usually no impact i% recommended storage conditions and "olding times in re%erencemet"ods are maintained2-mpact is monitored per sample batch only i LCS samples areprepared on receipt and stored %ith ield samples3 Field spi'ed samples or stability studysamples included in some method $alidation studies may also relect these contributors3 Field$ariability (FS/D!) is only considered %hen lab is responsible or sampling3

Usually no impact i% recommended storage conditions and "olding times in re%erencemet"ods are maintained2 -mproper storage such as sorbent tubes stored %ith bul' sol$entsamples or near sol$ent sources may ad$ersely aect data3 -mpact is monitored only i LCS isprepared on receipt 6 stored %ith ield samples3 Field blan' can be used to assesscontamination rom collection, transport, and storage3

.TE:his primarily applies to bul'/solid samples %hich re"uires use o laboratory duplicatesample data to determine impact on uncertainty3 -t is not applicable or LCS/LCSD mediaspi'e duplicates3

NA or Class A7 applies or graduated tubes or cylinders, etc3

Chromatographic pea' -D, intererence corrections, etc3 ust use inter1analyst instead ointra1analyst repeat data, %here applicable3


4/18

8ariation in instrument response and calibration process

Due to matri&, inter1element eects, co1eluting 5C pea's, etc3

2btain rom certiicate or estimate, can be ignored i less than 9/: o the largest contributor3

Similar to e&tractant bac'ground eects under Sample !reparation abo$e3

ay aect complete dissolution o analyte or loss o material in some cases3

Changes in conditions due to sample si#e, customer re"uests, etc3

ay $ary by lot or manuacturer7 also applies to diusion rates or passi$e monitors3

.hen signiicant and %hen data are blan' corrected3

.hen allo%ed3

anual, spreadsheet, L-S, etc3

' (N2* N2 LCS/LCSD duplicate spi'ed sampling media)

-mpact o high samples on ollo%ing sample readings7 can be monitored by proper use oCCBs3

Due to analysts, balances, dispensing de$ices used, etc

2nly has impact %hen LCS data are used to correct customer sample results3 2btain romcertiicate or estimate3 Can be ignored i less than 9/: o the largest contributor3 Note that useo an LCS %ith a large uncertainty can result in o$er estimation o o$erall analyticaluncertainty3

ypically pro$ided by the customer3 his is not part o analytical uncertainty, but must beconsidered by labs pro$iding sampling and pro$iding combined sampling and analyticaluncertainty3

o sampling method $alidation3 Should be considered only %hen laboratory

nd typically ta'en through the entire analytical process %ith each sample


5/18

Contributors to Uncertainty Comments to Clari%y Contributor E%%ects

Transportation/Storage/Handling

shipping time, container 6 temperature NA Limited impact on most sorbent tubes

lab storage time, conditions 6 temperature NA

contamination in lab storage areas NA


sample nonhomogeneity NA Not applicable to sorbent tube analysis

blending techni"ues NA Not applicable to sorbent tube analysis

sample si#e NA Not applicable to sorbent tube analysis

Sample Preparation:

$olumetric glass%are LCS Same type o glass%are used or samples and LCS

dispensing de$ice LCS Same type o dispensing de$ice

balance NA Not applicable to sorbent tube analysis

temperature NA Not applicable to sorbent tube analysis

sample e&traction LCS Applies to LCS i goes through sample preparation

e&tractant bac'ground LCS, B Analyte or intererant in sol$ents or other prep reagents used, etc3


temperature $ariance LCS LCS results relect any temperature eects on chromatography instrument

humidity $ariance NA Not applicable to sorbent tube analysis

Analysts:

dierent analysts LCS LCS results relect $ariability due to dierent analysts, as applicable, on die

analyst training le$el 6 e&perience LCS LCS results relect $ariability due to dierent analysts, as applicable, on die

data interpretation by analyst LCS LCS results relect $ariability due to dierent analysts, as applicable, on die


instrument stability LCS LCS results relect instrument $ariability on dierent days

carry o$er eects LCS LCS results relect instrument $ariability on dierent days

day to day calibration dierences LCS LCS results relect instrument $ariability on dierent days

intererences LCS LCS results relect instrument $ariability on dierent days

Calibration Standards/+e%erence Materials:

preparation $ariances LCS

calibration stoc' material uncertainty C*+-F-CA* 2btain rom certiicate or estimate

LCS reerence material uncertainty C*+-F-CA*

Test Procedure -ariations

$ariation %ithin and bet%een reagent lots LCS LCS sub;ected to same treatment as customer samples

e&traction or digestion times and temps LCS LCS sub;ected to same treatment as customer samples

sample dependent modiications LCS LCS sub;ected to same treatment as customer samples

E*ample o% Contributors to Measurement UncertaintyC"emical Analyses o% Sorbent Tubes using C"romatograp"y

See E*ample Calculations #to t"e rig"t o% t"e table&

+epresentative andApplicable 'C ,ata

sually no impact i recommended storage conditions and hold times are masamples are representati$e i prepared on receipt 6 stored %ith ield sampleimpact i recommended storage conditions and holding times are maintainedsamples or stability study samples included in some method $alidation studithese contributors3

sually no impact i appropriate storage conditions are maintained3 Field blaassess contamination rom collection, transport, and storage

Due to analysts, dispensing de$ices used, etc

se i customer sample data corrected or desorption eiciency3 2btain romestimate3

d ti i i i ithi d b t l t


6/18

0 a ora ory on ro an ar , ypca y a en roug e en re anay ca process % eac sampe a c

B 0 ethod or matri& blan'

NA 0 Not Applicable


7/18

*&amples o Analytical easurement ncertainty or Analysis o 2rganic Sol$ents on Charcoal ubes

LCS mg LCS 9=3= =3=>@ 9=@3 =3=>: @3=

=3=> 3= =3=>= >3= =3=? >3@ =3=>9 :3?

=3=>@? 9==3= =3=>> 3= =3=>: 9=:3@ =3=> 3

=3=>: @3= =3=>9 ?3= =3=: 993= =3=>? 9==3>

=3=?> 93= =3=?> 93= =3=>? 9=3@ =3=>9 3

=3=?> 3= =3=>=@ :3= =3=?= >@3? =3==? 9=3@

=3=>= >3= =3=>= >3= =3=@: ?>3= =3=@?@ ?>3=

=3=> 3= =3=>@? 9==3= =3=:: 993 =3=>?= 9==3:

=3=>> 3= =3=>@? 9==3= =39== 939 =3= 9=@3@

=3=>= >3= =3=>= >3= =3=>? 993 =3=:: 9=?3@

=3=>?@ 9=93= =3=>> 3= =3=>@ 9=3= =3=9 9=@3=

=3=>: @3= =3=>> 9=3= =3=9: 993? =3=?@ >?3

=3=>> 9=3= =3=9 9=@3= =3=??= 39 =3== 9=@39

=3=>@? 9==3= =3=>: 9=:3= =3=9= 993: =3=@= 99=3?

=3== 9=3= =3=>> 9=3= =3=>: 9=3? =3=> 9=?3=

=3=>= >3= =3=>?@ 9=93= =3=> 993 =3=>> 9=3=

=3=>?@ 9=93= =3== 9=3= =3=>? 9=?3? =3=>@9 3:

=3=>: @3 =3=> 9=3 =3=>= 3 =3=@ ?3

=3=>9 3 =3=>9 :3? =3=@ 993: =3=@ 99=3:

=3=?? 93 =3=?> =3 =3=? 9=3 =3=>> 9=3

34 point Mean 5 +ec 6728 34 point Mean 5 +ec 9429

34 point Std ,ev 324 34 point Std ,ev 992;+S, 324;5 +S, 99285

7295 5 8825 5 $9275 295

.o signi%icant bac1ground in met"od blan12 .o signi%icant bac1ground in met"od blan12

mg oluene on Charcoal ube using CS

Desorption per N-2S4 9=9LCS/LCSD 0 =3=>@? mg toluene spi'e/tube

mg n1Butanol on Charcoal ube using CS

Desorption per N-2S4 9=9odLCS/LCSD 0 =3=>9= mg n1butanol spi'e /tube

(includes correction or D* 0 =3>=)

LCSD8

E*panded MU =6;5 Con% 1>8

E*ample o% reporting %or 4247; mg toluene:4247; mg toluene 0it" an analytical uncertainty o% ?/$4244@ mg at t"e 6;5 con%idence level 0it" probable biaso% $42448 mg

E*ample o% reporting %or 4247; mg n>butanol: 424butanol 0it" an analytical uncertainty o% ?/$ 424966;5 con%idence level 0it" probable bias o% 4244


8/18


9/18

certaintyide by 899285

; mg n$g at t"eg


10/18


11/18

Contributors to UncertaintyTransportation/Storage/Handling

shipping time, container 6 temperature NA

lab storage time, conditions 6 temperature NA

contamination in lab storage areas NA


sample nonhomogeneity D!

blending techni"ues D!

sample si#e D!

Sample Preparation:$olumetric glass%are LCS, D!

dispensing de$ice LCS, D!

balance LCS, D!

temperature LCS, D!

sample e&traction LCS, D!

e&tractant bac'ground LCS, D!, B


temperature $ariance NA

humidity $ariance NA

Analysts:

dierent analysts LCS, D!

analyst training le$el 6 e&perience LCS, D!

data interpretation by analyst LCS, D!


instrument stability LCS

carry o$er eects LCS, D!

day to day calibration dierences LCS

intererences D!, S

Calibration Standards/+e%erence Materials:

preparation $ariances LCS, D!

calibration stoc' material uncertainty C*+-F-CA*

LCS reerence material uncertainty NA

Test Procedure -ariations

$ariation %ithin and bet%een reagent lots LCS

e&traction or digestion times and temps LCS

sample dependent modiications LCS

*amp e o on r u ors o easuremen n

C"emical Analyses o% Lead #Pb& in Paint usin

+epresentativeand Applicable

'C ,ata


12/18

NA

,ata Manipulation:

sampling media blan' correction NA

instrument blan' correction LCS

Accuracy o calculations LCS

D! 0 Duplicate, resulting rom sub1sampling o a bul' (

FB 0 Field Blan'

FS 0 Field Spi'e

B 0 ethod or matri& blan'

NA 0 Not Applicable

desorption eiciencies %ithin and bet%een lots orsorbent tubes

LCS 0 Laboratory Control Standard, matri& matched andsample batch


13/18

*&amp

Comments to Clari%y Contributor E%%ects

No impact on bul' paint samples rom transportation, storage or normal handl ing

93 =>3>

9>3@ =>3>

9? =

Sample composition, etc3 9>@ =

Stirring, sie$ing, grinding, etc 9> =>3>

Large enough to allo% ade"uate subsampling 9> =>3>

@9 =>:9 =

pipettes, and other types o dispensers not Class A 9? =>3>

balance error is oten insigniicant compared to other sources 9?? =>3>

4ot plate or ashing temperatures : =

Applies to LCS or D! i goes through sample preparation >> =

Analyte or intererant in acids, or other reagents 9> =>3>

=? =>3>

No impact on bul' paint samples > =

No impact on bul' paint samples 9 =

9> =>3>

9>? =>3>

9 =

>= =

9? =>3>

Baseline drit, repeatability o a$eraged readings, etc 9>@ =>3>

=

:= =

9>> =>3>

= =>3>

9? =

2btain rom certiicate or estimate :== =

Sample results not corrected or LCS reco$ery =: =>3>

9= =>3>

Similar to e&tractant bac'ground eects under Sample !reparation abo$e 4 point Mean 5 +ec2

ay aect complete dissolution o analyte or loss o material in some cases 4 point Std ,ev

Changes in conditions due to sample si#e, customer re"uests, etc +S,

cer a n y

g CP$AESee E*ample Calculations #to t"e rig"t o% t"e table&

!b in !aint using hotbloc' acidAnalysis in accordance %ith *!

(od)LCS +eco$ery o !aint S+ >

or S+ >9 at = E/

LCSmg/g

rue$aluemg/g

NA or Class A7 applies or graduated tubes or cylinders, etc3

Analyst contributors aect all aspects o analysis rom subsampling through datamanipulation

-mpact o high samples on ollo%ing sample readings7 can be monitored by properuse o CCBs

Due to matri&, inter1element eects, etc3 Cannot be routinely determined ortypical industrial hygiene sampling media

Due to analysts, balances, dispensing de$ices used, etc


14/18

No sampling media %ith bul' samples

%hen allo%ed

anual, spreadsheet, L-S, etc

2* N2 LCS/LCSD duplicate spi'ed sampling media)

334

E*ample aE*panded

ypically ta'en through the entire analytical process, %ith each

E*ample3344 mg/con%idenc


15/18

les o Analytical easurement ncertainty or Lead in !aint

LCS < +ec C8

:3@ 9@= 9= ?39 =3=@ =3==

=3> 99 @= @3: =399@ =3=9:

3@ ?= >? ?>3== =3=: =3==?

:3 9@9 : >3=> =3:?>@ =39::

>>39 9@>: 999 93:: =39: =3=9

>>39 @ >:= >39= =3=> =3=9==

9=:3 :?= @?= 93=: =3=>?@ =3==??9=?3@ @ ?:= ?3 =39=@ =3=9=

>3? ?: ? 9??3> =3?= =3=>>

>3> :=== === ?=?399 =3=:9 =3==9=

9=939 99= 9:== =3=@ =3=9@ =3===

9=>3 9=:= 9 >39> =3=>?@ =3==??

3> ?= > 9=?3> =3=9>@ =3===:

39 9= 9 39 =3=?@ =3==@:

3: ?=? @? @93=: =3=@>: =3==?

9==3 9@ 9>@ ?3=? =3=:?= =3==9

>>39 99= 9:== 9>3 =3=9=: =3===9

>3@ 9?9= 9?9= 9=9>3: =3=@= =3==:>

9=93 99>? 99 :3 =3==:= =3====

9=3= @ @ 9:3 =3==9 =3====

>3? = :9> ?3@ =3=> =3==:9

>39 9? 9? >@3:> =39@9 =3=@=

3 :? :=@> =3? =39>: =3=:

3> :=@ ?93: =39= =3=@

=3= :9@= :== @@3? =39>@ =3=9@

@3? >9= :=== 9?3>@ =3=: =3==

:3 >@= := 3= =3== =3====

3> 99:: 99 3@@ =3=== =3====

?3 99 @ :>3> =3:9 =3=

93= ??? :@@ =3> =3:?= =39?@

632@ 42@43

2 429;3

2@5

digestion and -C!1A*SA S.>@ :== 6 @=9=

at =>3> E/1 3 mg/g

1 99= mg/g !b

Sample duplicata data in mg/g or !b in !aint usinghotbloc' acid digestion and -C!1A*S in accordance %ith

*!A S.1>@ :== 6 @=9= (od)

mg/gSample

mg/gSple Dup

Std De$(S) C8

D C-8

C-pooled > #DC-8/4& > 9;25


16/18

E*panded MU = 6;5 Con% #1>8& > $;25

4 mg/1g $424; > 828 mg/1g

+e%erence material used %or calibration indicates concentration and e*pandeduncertainty o% 9449 ?/$ ; ug/mL at 6;5 con%idence level2 E*panded uncertaintydivided by 8 to yield 428; 5 +el2 S,2 nsigni%icant compared to 9;285 and canbe eliminated %rom calculation2 .o signi%icant bac1ground in

met"od blan12

Combined +el2 Std ,ev #S,c& > F S,98? S,88G

S,c > F#2@&8? #9;2&8G > 92@5

235

nalytical uncertainty %or 3344 mg/Bg Pb in paint sample:analytical uncertainty o% 3344 mg/Bg Pb in paint > 3344 423> 93@4 mg/1g

% reporting %or 3344 mg/Bg Pb in paint: g Pb in paint 0it" an analytical uncertainty o% ?/$ 9;44 mg/Bg at t"e 6;5

level and a probable bias o% $84 mg/Bg


17/18

+S,


18/18

example chemistry measurement uncertainty calculations v3 corrected 031312.xls

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