1. EUROMET/METCHEM comparison PCB congeners in organic solution F. Ulberth

2. PCBs Belong to 12 POPs (UNEP) Minimisation and phase-out programmes:
Basel Convention
OSPAR Convention: close to zero concentrations in the marine environment
Convention on the protection of the marine environment of the Baltic Sea Area
UNECE POPs Protocol to the Convention on long- range transboundary air pollution: to reduce the emissions of POPs
Stockholm Convention (POPs Convention)

3. Background - EU
Community strategy for dioxins, furans and polychlorinated biphenyls (COM(2001) 593 final) Measurement methods and standards: …in order to obtain comparable, consistent, reliableand high quality measurement results it is necessary toimplement a high quality measurement standard at Community level.

4. Suite of congeners studied
IUPAC
Congener PCB 28
2,4,4’- Trichlorobiphenyl 52
2,2’,5,5’- Tetrachlorobiphenyl
101
2,2’,4,5,5’- Pentachlorobiphenyl
118
2,3’,4,4’,5- Pentachlorobiphenyl
138
2,2’,3,4,4’,5’- Hexachlorobiphenyl
153
2,2’,4,4’,5,5’- Hexachlorobiphenyl
180
2,2’,3,4,4’,5,5’- Heptachlorobiphenyl

5. Sample distribution 30 Nov 04 by courier service
four ampoules of IRMM solution ( ng/g each)
four ampoules of LGC solution ( ng/g each, in addition 8 other congeners)
Electronic reporting sheet
Reporting requirements: independent duplicates from three ampoules (in ng/g), uncertainty estimate, details of analysis
Deadline: 15 Jan 05

6. Participants and techniques
Institute
Technique IS
Calibration
Uncertainty budget
IRMM (EC)
GC-MS
labelled
crystalline
Yes
LGC (UK)
IMGC (IT)
external
BCR solution
BAM (DE)
NIST solution
LNE (FR)
VNIIM (RU)
LGC Promochem
UKRCSM (UA)
SUPELCO solution No
VITUKI (HU)
JORDFORSK (NO)
internal
EHRENSTORFER solution

7. Capillary columns HP-5MS + DB-35MS (60 m x 0.25 mm)
DB-XLB (30 m x 0.25 mm)
HT-8 (50 m x 0.22 mm)
poly(5%diphenyl/95%dimethyl)siloxane (30 m x mm)
DB-17MS (60 m x 0.25 mm)
VF-5ms (30 m x 0.25 mm)
HT-8 (40 m x 0.18 mm)
RTX5MSi (30 m x 0.25 mm)

8. IRMM solution – PCB28

9. LGC solution – PCB28

10. IRMM solution – PCB52

11. LGC solution – PCB52

12. IRMM solution – PCB101

13. LGC solution – PCB101

14. IRMM solution – PCB118

15. LGC solution – PCB118

16. IRMM solution – PCB138

17. LGC solution – PCB138

18. IRMM solution – PCB153

19. LGC solution – PCB153

20. IRMM solution – PCB180

21. LGC solution – PCB180

22. %-Deviation from known IRMM values
LGC
BAM
LNE
UKCR SM
Jord- forsk
VITUKI
VNIIM
PCB 28
-5.9
2.0
0.0
-12.5
-44.3
-21.0
-20.2
-6.0
PCB 52
-3.0
1.8
-0.4
-8.1
-24.6
-17.2
-17.1
-9.5
PCB 101
-4.7
0.1
-2.6
-10.8
-25.0
-18.1
-14.2
PCB 118
-3.8
2.1
-6.4
-57.1
-30.7
-16.0
-16.7
PCB 138
-1.4
2.9
1.4
-29.2
-28.8
-10.2
-11.6
PCB 153
0.8
0.6
-8.7
-18.3
-9.8
-12.7
-8.4
PCB 180
1.9
1.5
-1.6
-15.7
-22.2
-22.6
-12.6
-6.9

23. Reported uncertainties vs repeatability IRMM solution
LGC
BAM
LNE
VNIIM
2*sd U
PCB 28
1.7
2.1
0.5
0.6
0.7
0.8
1.4
0.4
0.9
PCB 52
1.8
2.4
1.0
2.0
3.1
PCB 101
2.3
3.4
1.9
2.2
3.7
PCB 118
3.2
1.1
2.6
6.4
1.2
5.3
PCB 138
3.9
1.3
2.5
PCB 153
1.5
PCB 180
0.2
U – expanded uncertainty (95 %)

24. Reported uncertainties vs repeatability LGC solution
IRMM
LGC
BAM
LNE
IMGC
VNIIM
2*sd U
PCB 28
17.7
37.5
5.2
6.3
58.7
59.0
54.4
31.8
--*) --
7.0
13.9
PCB 52
9.7
27.6
4.2
6.8
51.7
53.8
47.1
45.3
44.4
83.0
6.6
11.4
PCB 101
19.2
40.5
5.8
11.1
28.3
31.0
24.6
39.3
70.9
14.7
PCB 118
15.7
33.8
4.4
9.9
56.7
90.2
18.3
28.1
134.2
80.6
9.6
20.9
PCB 138
14.5
35.3
9.2
34.5
36.6
32.6
31.5
105.6
69.0
15.9
PCB 153
14.1
31.3
3.1
8.2
26.9
27.2
27.9
38.8
12.2
18.6
PCB 180
21.6
36.8
5.7
12.8
30.6
33.2
71.4
79.0
71.6
8.8
21.4
U – expanded uncertainty (95 %)
*) co-eluting substances

25. IRMM uncertainty budget
expanded uncertainty k
coverage factor (k=2) c
average concentration of the analyte
u(cst)
uncertainty of standards used (purity, mass)
RSDRF
relative standard deviation of response factor determined n
number of standards used for RF determination
RSDresult
relative standard deviation of results (analyte concentration)

26. LGC uncertainty budget
Measurement equation
wi: mass fraction of PCB in sample X
wZ: mass fraction of PCB in primary standard Z
mY: mass of spike Y added to the sample X to prepare the blend B (=X+Y)
mX: mass of sample X added to the spike Y to prepare the blend B (=X+Y)
mZc: mass of primary standard solution Z added to the spike Y to make calibration blend Bc (=Y+ Z)
mYc: mass of spike Y added to the spike Y primary standard solution Z to make calibration blend Bc (=Y+ Z)
R’B: measured isotope amount ratio of sample blend (X+Y)
R’Bc: measured isotope amount ratio of calibration blend (Bc=Z+Y)
wi: mass fraction of the individual measurement results
: average of the 6 individual mass fractions
n: number of individual values averaged (here n = 6)

27. BAM uncertainty budget
Major contributions to the combined uncertainty of the mean:
precision of the method
concentration of the calibration solution
standard deviation of the six replicates taken as method precision (includes precision associated weighing the sample, spiking and calibration etc)
expanded uncertainty of NIST SRM-1493 divided by 2
standard deviation of replicate measurements and standard uncertainty of the calibration standard combined (the 1/sqr(n) reduction was not applied)
coverage factor k=2 for expanded uncertainty

28. LNE uncertainty budget
Uncertainty estimation (GUM compliant) using WINCERT software taking into account:
Masses
Uncertainty concentration of SRM used for calibration
Uncertainty of compound purity
Ratio measurement in sample
Ratio measurement in standard
Fidelity

29. IMGC uncertainty budget
Contributions to combined standard uncertainty:
calibration curve
repeatability of readings of sample measurements
calibration curves determined by Weighted Least Squares

30. VNIIM uncertainty budget
Contributions to combined standard uncertainty
RSD of calibration solution
standard uncertainty of gravimetric preparation of standard solution
standard uncertainty of gravimetric preparation of sample solution
RSD of response factor
RSD of the mean of the six individual results

31. Conclusions
Agreement of results among participants not fully satisfactory
Agreement of individual results with gravimetric preparation values not fully satisfactory
Not all participants provided uncertainty budgets
Harmonisation of uncertainty budgets necessary

32. Outlook
Option 1: Repeat comparison on new set of PCBs in organic solution
Option 2: Repeat comparison on new set of PCBs in organic solution plus common quality control sample (either “old” IRMM or LGC solution)
Option 3: Repeat comparison on new set of PCBs in organic solution plus (i) common quality control sample (either “old” IRMM or LGC solution) and (ii) extract of real sample (soil / sludge)