of 18
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
7/26/2019 Example Chemistry Measurement Uncertainty Calculations V3 corrected 031312.xls
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 $olume sampled NA
.here
D! 0 Duplicate, resulting rom sub1sampling o a bul
FB 0 Field Blan'
B 0 ethod or atri& Blan'
NA 0 Not Applicable
Calibration Standards/+e%erenceMaterials:
e&traction or digestion times, temperatures,and conditions
desorption eiciencies %ithin and bet%eenlots or sorbents
FS 0 Field Spi'e 1 Not typically conducted unless part
is responsible or ield sampling3LCS 0 Laboratory Control Standard, matri& matchedbatch
7/26/2019 Example Chemistry Measurement Uncertainty Calculations V3 corrected 031312.xls
3/18
Comments to Clari%y Contributor E%%ects
Sample composition, etc3
Stirring, sie$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$ersely aect data3 -mpact is monitored only i LCS isprepared on receipt 6 stored %ith ield samples3 Field blan' can be used to assesscontamination rom collection, transport, and storage3
.TE:his primarily applies to bul'/solid samples %hich re"uires use o laboratory duplicatesample data to determine impact on uncertainty3 -t is not applicable or LCS/LCSD mediaspi'e duplicates3
NA or Class A7 applies or graduated tubes or cylinders, etc3
Chromatographic pea' -D, intererence corrections, etc3 ust use inter1analyst instead ointra1analyst repeat data, %here applicable3
7/26/2019 Example Chemistry Measurement Uncertainty Calculations V3 corrected 031312.xls
4/18
8ariation in instrument response and calibration process
Due to matri&, inter1element eects, co1eluting 5C pea's, etc3
2btain rom certiicate or estimate, can be ignored i less than 9/: o the largest contributor3
Similar to e&tractant bac'ground eects under Sample !reparation abo$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
7/26/2019 Example Chemistry Measurement Uncertainty Calculations V3 corrected 031312.xls
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
Laboratory Subsampling
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
Lab Environmental Conditions:
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
Measuring nstruments:
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
7/26/2019 Example Chemistry Measurement Uncertainty Calculations V3 corrected 031312.xls
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
7/26/2019 Example Chemistry Measurement Uncertainty Calculations V3 corrected 031312.xls
7/18
*&les 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
7/26/2019 Example Chemistry Measurement Uncertainty Calculations V3 corrected 031312.xls
8/18
7/26/2019 Example Chemistry Measurement Uncertainty Calculations V3 corrected 031312.xls
9/18
certaintyide by 899285
; mg n$g at t"eg
7/26/2019 Example Chemistry Measurement Uncertainty Calculations V3 corrected 031312.xls
10/18
7/26/2019 Example Chemistry Measurement Uncertainty Calculations V3 corrected 031312.xls
11/18
Contributors to UncertaintyTransportation/Storage/Handling
shipping time, container 6 temperature NA
lab storage time, conditions 6 temperature NA
contamination in lab storage areas NA
Laboratory Subsampling
sample nonhomogeneity D!
blending techni"ues D!
sample si#e D!
Sample Preparation:$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 NA
humidity $ariance NA
Analysts:
dierent analysts LCS, D!
analyst training le$el 6 e&perience LCS, D!
data interpretation by analyst LCS, D!
Measuring nstruments:
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
$ariation %ithin and bet%een reagent lots LCS
e&traction or digestion times and temps LCS
sample dependent modiications LCS
*amp e o on r u ors o easuremen n
C"emical Analyses o% Lead #Pb& in Paint usin
+epresentativeand Applicable
'C ,ata
7/26/2019 Example Chemistry Measurement Uncertainty Calculations V3 corrected 031312.xls
12/18
NA
,ata Manipulation:
sampling media blan' correction NA
instrument blan' correction LCS
Accuracy o calculations LCS
D! 0 Duplicate, resulting rom sub1sampling o a bul' (
FB 0 Field Blan'
FS 0 Field Spi'e
B 0 ethod or matri& blan'
NA 0 Not Applicable
desorption eiciencies %ithin and bet%een lots orsorbent tubes
LCS 0 Laboratory Control Standard, matri& matched andsample batch
7/26/2019 Example Chemistry Measurement Uncertainty Calculations V3 corrected 031312.xls
13/18
*&
Comments to Clari%y Contributor E%%ects
No impact on bul' paint samples rom transportation, storage or normal handl ing
93 =>3>
9>3@ =>3>
9? =
Sample composition, etc3 9>@ =
Stirring, sie$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$ices used, etc
7/26/2019 Example Chemistry Measurement Uncertainty Calculations V3 corrected 031312.xls
14/18
No sampling media %ith bul' samples
%hen allo%ed
anual, spreadsheet, L-S, etc
2* N2 LCS/LCSD duplicate spi'ed sampling media)
334
E*ample aE*panded
ypically ta'en through the entire analytical process, %ith each
E*ample3344 mg/con%idenc
7/26/2019 Example Chemistry Measurement Uncertainty Calculations V3 corrected 031312.xls
15/18
les o Analytical easurement ncertainty or Lead in !aint
LCS < +ec C8
:3@ 9@= 9= ?39 =3=@ =3==
=3> 99 @= @3: =399@ =3=9:
3@ ?= >? ?>3== =3=: =3==?
:3 9@9 : >3=> =3:?>@ =39::
>>39 9@>: 999 93:: =39: =3=9
>>39 @ >:= >39= =3=> =3=9==
9=:3 :?= @?= 93=: =3=>?@ =3==??9=?3@ @ ?:= ?3 =39=@ =3=9=
>3? ?: ? 9??3> =3?= =3=>>
>3> :=== === ?=?399 =3=:9 =3==9=
9=939 99= 9:== =3=@ =3=9@ =3===
9=>3 9=:= 9 >39> =3=>?@ =3==??
3> ?= > 9=?3> =3=9>@ =3===:
39 9= 9 39 =3=?@ =3==@:
3: ?=? @? @93=: =3=@>: =3==?
9==3 9@ 9>@ ?3=? =3=:?= =3==9
>>39 99= 9:== 9>3 =3=9=: =3===9
>3@ 9?9= 9?9= 9=9>3: =3=@= =3==:>
9=93 99>? 99 :3 =3==:= =3====
9=3= @ @ 9:3 =3==9 =3====
>3? = :9> ?3@ =3=> =3==:9
>39 9? 9? >@3:> =39@9 =3=@=
3 :? :=@> =3? =39>: =3=:
3> :=@ ?93: =39= =3=@
=3= :9@= :== @@3? =39>@ =3=9@
@3? >9= :=== 9?3>@ =3=: =3==
:3 >@= := 3= =3== =3====
3> 99:: 99 3@@ =3=== =3====
?3 99 @ :>3> =3:9 =3=
93= ??? :@@ =3> =3:?= =39?@
632@ 42@43
2 429;3
2@5
digestion and -C!1A*SA S.>@ :== 6 @=9=
at =>3> E/1 3 mg/g
1 99= mg/g !b
Sample duplicata data in mg/g or !b in !aint usinghotbloc' acid digestion and -C!1A*S in accordance %ith
*!A S.1>@ :== 6 @=9= (od)
mg/gSample
mg/gSple Dup
Std De$(S) C8
D C-8
C-pooled > #DC-8/4& > 9;25
7/26/2019 Example Chemistry Measurement Uncertainty Calculations V3 corrected 031312.xls
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
7/26/2019 Example Chemistry Measurement Uncertainty Calculations V3 corrected 031312.xls
17/18
+S,
7/26/2019 Example Chemistry Measurement Uncertainty Calculations V3 corrected 031312.xls
18/18