RepresentativeSubsampling at theLaboratory:New Guidance From USEPA
RepresentativeSubsampling at theLaboratory:New Guidance From USEPA
Jeffrey C. MyersAugust 18, 2004Jeffrey C. MyersAugust 18, 2004
2
3
John Wiley & Sons 1997
4
THE SEVEN “DEADLY” SAMPLING ERRORS
FUNDAMENTALERROR
FE
INCREMENTEXTRACTIONERROR EE
PREPARATIONERROR PE
INCREMENTDELIMITATION
ERROR DE
GROUPING &SEGREGATION
ERROR GE
LONG-RANGEFLUCTUATION
ERROR CE2
PERIODICFLUCTUATION
ERROR CE3
5
John Wiley & Sons 1997
6
COMPOSITIONAL CH
DISTRIBUTIONAL DH
FORMS OF HETEROGENEITYFORMS OF HETEROGENEITY
7
ZERO DIMENSIONAL LOTZERO DIMENSIONAL LOTZERO DIMENSIONAL LOT
DEFINITIONOF CH
DEFINITIONOF CH
DEFINITIONOF DH
DEFINITIONOF DH
8
THE TRIAD APPROACH FROM EPA
9
Uncertainties add as vectors (aUncertainties add as vectors (a22 + b + b22 = c = c22))
AA
3 X3 X
Total Uncertainty AnalyticalUncertainty
Sampling Uncertainty
CC1/3 X1/3 X
AACCBB
BB
10
Sampling = 95%
Analytical = 5%Analytical = 5%
39,800 On-site41,400 Lab
500 On-site416 Lab
164 On-site136 Lab
27,800 On-site42,800 Lab
24,400 On-site27,700 Lab
1,280 On-site1,220 Lab
1
27
6 3
45
331 On-site 286 Lab
11
12
John Wiley & Sons 1997
13
John Wiley & Sons 1997
14
John Wiley & Sons 1997
15
MASSDFE ))(5.22( 3
2 =
� FE = FUNDAMENTAL ERROR� D = DIAMETER OF LARGEST
PARTICLE� MASS = MASS OF ANALYZED PORTION
16
SAMPLE MASS APPROX. ERROR 1 gm 40% 2 gm 30% 5 gm 20% 10 gm 15% 20 gm 10% PARTICLE SIZE = 2mm
SAMPLE MASS APPROX. ERROR 1 gm 40% 2 gm 30% 5 gm 20% 10 gm 15% 20 gm 10% PARTICLE SIZE = 2mm
RELATIVE FUNDAMENTAL ERROR: PARTICLESIZE REPRESENTATION
(RAMSEY 1990)
RELATIVE FUNDAMENTAL ERROR: PARTICLESIZE REPRESENTATION
(RAMSEY 1990)
17
John Wiley &
Sons 1997
18
19
� CONING & QUARTERING� ALTERNATE SHOVELING� FRACTIONAL SHOVELING� RIFFLE SPLITTERS
� CHUTE� ROTARY
� CONING & QUARTERING� ALTERNATE SHOVELING� FRACTIONAL SHOVELING� RIFFLE SPLITTERS
� CHUTE� ROTARY
SUBSAMPLING METHODSSUBSAMPLING METHODSSUBSAMPLING METHODS
20
CONING&
QUARTERING
CONING&
QUARTERING
21
RIFFLE SPLITTERSRIFFLE SPLITTERS
22
CORRECT ANDINCORRECTSAMPLINGDEVICES
CORRECT ANDINCORRECTSAMPLINGDEVICES
23
SCOOPSCOOP
24
SPATULASPATULA
25
JAPANESESLABCAKE
JAPANESESLABCAKE
26
CORRECT DELIMITATION WITH JAPANESE SLAB CAKES
27
28
SUMMARY
- PIERRE GY’S SAMPLING THEORY- EPA/600/R-03/027- http://cluin.org/publications/db/db_search.cgi?new=1&title=1&submit_search=1