intercomparison of enriched stable isotope reference materials for ...

- NAHRES-5Vienna, 1991

INTERCOMPARISON OF

ENRICHED STABLE ISOTOPE REFERENCE MATERIALS

FOR MEDICAL AND BIOLOGICAL STUDIES

by

R.M. Parr and S.A. Clements

INTERNATIONAL ATOMIC ENERGY AGENCY

1. INTRODUCTION

This report summarizes the results of an intercomparison exercise organized by IAEAduring the latter part of 1988 and 1989. Data is presented for 13 different kinds of enrichedstable isotope reference material containing 2H, 13C, 15N and 18O. Results were submitted by40 participants in 20 countries (Annex 2).

2. DESCRIPTION OF THE MATERIALS

3H-labelled water (IAEA-302): Two deuterium-labelled water samples (-500 and-1000 7oo 2H vs VSMOW) were made from highly enriched (99.8 atom percent 2H)deuterium oxide, which was diluted with natural-abundance distilled water. The labelling waschecked by reduction over Zn to HD gas. The samples are sterile and pyrogen free.

13 C-labelled sodium bicarbonate (IAEA-303): Two sodium bicarbonate referencematerials (-100 and -450 7 0 0

13C vs VPDB) were prepared from NaH13CO3 (isotopic purity- 99 atom percent), made up in distilled water and assayed for total CO2 by acidification ina vacuum line and manometric assay.

I8O-labeUed water (IAEA-304): Two 18O-labelled water samples (-250 and -500 7OO18O vs VSMOW) were made from enriched l8O-water (20 atom percent '8O), which wasdiluted with natural-abundance distilled water. The labelling was checked by CO2 isotopicexchange. The samples are sterile and pyrogen free.

'*N-labelled ammonium sulphate (IAEA-305): Two materials (-40 and -400 7 o 0 15N

vs air) were prepared from highly enriched I5N-labelled ammonium sulphate by dilution withthe unlabelled compound in bidistilled water. After mixing, evaporation, freeze drying,crystallization and further mixing, the material was transferred to the IAEA in small vialscontaining approximately 100 mg each and stored at room temperature. (See also IAEA-311.)

"C-labelled UL-glucose (IAEA-309): Two uniformly 13C-labelled D-glucose standards(-100 and -550 °/oo

13C vs VPDB) were prepared by appropriate mixing of highly enriched(97 atom percent) UL-D-glucose and D-glucose at natural 13C-abundance. The water solublemixtures were recrystallized from H20/acetone (4°C) and the harvested crystals dried at 450Cfor 48 hours. The materials were presented to the IAEA for distribution as approximately100 mg UL-D-glucose in sealed glass ampoules to be stored at room temperature.

tsN-labeUed urea (JAEA-310): Two materials (-50 and -250 7OO 15N vs air) were

prepared from highly enriched 1SN-Iabelled urea by dilution with the unlabelled compound inbidistilled water. After mixing, evaporation, freeze drying, crystallization and furthermixing, the materials were transferred to the IAEA's laboratory. The final homogeneousproducts were dispensed into small vials containing approximately 100 mg each and storedat room temperature.

- 2 -

15N-labelled ammonium sulphate (IAEA-311): This material (-2 atom % 15N) wasprepared from highly enriched 15N-labelled ammonium sulfate by dilution with the unlabelledcompound in bidistilled water. After mixing, evaporation, freeze drying, crystallization andfurther mixing, the material was transferred to the IAEA in small vials containingapproximately 100 mg each and stored at room temperature. (See also IAEA-305.)

3. ORGANIZATION OF THE INTERCOMPARISON

The availability of these materials was announced in the Agency's AQCS catalogue [1]for 1988 and 1989, and also in a number of scientific journals catering to scientists who areusing enriched stable isotopes in medical, biological and agricultural studies. Interestedscientists were offered the possibility of obtaining the materials cost free in exchange for theiragreement to participate in an intercomparison exercise. Most of the participants weretherefore "self selected". In addition, however, a number of scientists known by the Agencyto be experts in this field were specifically invited to take part in the intercomparison.

All participants were requested to make at least three, but preferably six, separatedeterminations of each isotope and to report their results together with information on themethod used and its limit of detection (LOD). A report form was provided for this purpose.Methods were coded according to the scheme reproduced in Annex 1.

In order to preserve anonymity in respect of the actual results reported, each participantis identified in this report only by means of a laboratory code number. There is no relationbetween the laboratory code number and the order in which the addresses are listed inAnnex 2.

4. STATSSTICAL METHODS

The results of the intercomparison were evaluated by a computer program whichexamines the data for each analyte and reference material in turn. This procedure [2] hasbeen in use successfully for many years for evaluating the results of IAEA intercomparisons.

For each participant and analyte, the individual net results (up to six in number) arefirst reduced to a single mean value and its standard deviation. In the subsequent calculationseach of these is treated as a single unweighted value. Four different outlier tests (Dixon's,Grubb's, coefficient of skewness and coefficient of kurtosis) are then applied at a significancelevel of 5%. Any laboratory mean thereby identified as an outlier by one or the other ofthese tests is subsequently excluded from further consideration. The remaining "accepted"laboratory means, say "n" in number, are then combined in the usual way, without weighting,to provide estimates of the overall mean, x, and its associated standard deviation (SD),standard error and 95% confidence interval. The latter is defined as the range between theextreme lower and upper limits of the quantity (x ± c) where c = SD.tA^and t is the valueof Student's t on (n - 1) degrees of freedom at the 5% probability level (2-sided).

- 3 -

5. RESULTS

The results presented below are largely self explanatory. For each reference material,three kinds of output are provided: (1) a table of results listing the mean value and otherrelevant information reported by each laboratory, (2) a statistical summary of these results,and (3) a graphical representation of the results (plots). The tables and figures are in thefollowing order:

Table 1:Table 2:

Table 3:

Figure 1 :Figure 2:

Table 4:Table 5:

Table 6:

Figure 3:Figure 4:

Table 7:Table 8:

Table 9:Table 10:

2H in IAEA-302A (water)2H in IAEA-302B (water)

Statistical summary of results for 2H samples

2H in IAEA-302A (water)2H in IAEA-30?B (water)

18O in IAEA-304A (water)18O in IAEA-304B (water)

Statistical summary of results for 18O samples

18O in IAEA-304A (water)18O in IAEA-304B (water)

13C in IAEA-303A (sodium bicarbonate)13C in IAEA-3O3B (sodium bicarbonate)

13C in IAEA-309A (UL-g!ucose)13C in IAEA-309B (UL-glucose)

Table 11: Statistical summary of results for 13C samples

Figure 5: 13C in IAEA-303A (sodium bicarbonate)Figure 6: 13C in IAEA-303B (sodium bicarbonate)

Figure 7: 13C in IAEA-309A (UL-glucose)Figure 8: 13C in IAEA-309B (UL-glucose)

Table 12: ^N in IAEA-305A (ammonium sulphate)Table 13: 15N in IAEA-305B (ammonium sulphate)

Table 14: 15N in IAEA-31OA (urea)

Table 15: 15N ii. : \EA-310B (urea)

Table 16: 15N in IAEA-3Ii (ammonium sulphate)

Table 17: Statistical summary of results for 15N samples

- 4 -

Figure 9: 15N in IAEA-305A (ammonium sulphate)Figure 10: 15N in IAEA-305B (ammonium sulphate)

Figure 11 : "N in IAEA-310A (urea)

Figure 12: 15N in IAEA-310B (urea)

Figure 13: 15N in IAEA-311 (ammonium sulphate)

Table 18: Overview of all recommended values (see also section 6)

The following is some more information about the three different kinds of output:

Table of results The method codes are listed in Annex 1. In the column "mean", allvalues marked by an asterisk were identified as statistical outliers (see section 4). The lastcolumn (Lab LoD) refers to the Limit of Detection reported by each laboratory. (This valuehas not yet been used in any of the calculations.)

Statistical summary This is the output from the evaluation described in section 4. Themost important values to look at are in the last line, which gives the confidence interval forthe overall mean based only on the accepted results (i.e. excluding statistical outliers).

Plots Each point represents one set of results reported by one laboratory for onereference material. They have been arranged in numerical order from low to high. The errorbar represents the standard deviation. The number below the error bar is the number ofobservations. The code on top of the error bar represents the method code (first twocharacters only). Results that were identified as outliers are listed but not plotted. Thedashed horizontal lines indicate the 95% confidence interval (taken from the bottom line ofthe statistical summary table).

6. CERTIFICATION

The overall means of accepted laboratory averages (i.e. after removal of statisticaloutliers) are hereby proposed by IAEA to be the recommended values. These, together withtheir 95% confidence intervals, may be regarded as provisional certified values. Anoverview is presented in Table 18.

These recommended values will remain in force pending a more detailed evaluation ofthe results so far submitted, and of any new results that may be provided in the meantime.This new evaluation will take account of comments, if any, submitted by individualparticipants and will also place greater weight on an appraisal of the sample preparationprocedures and analytical methods actually employed. It will be conducted by expertsappointed by IAEA, probably during 1991.

- 5 -

7. ACKNOWLEDGEMENTS

This intercomparison would not have been possible without the assistance of manypersons and institutes. IAEA would like to thank all persons who submitted analytical results,and is particularly grateful to the following institutes and persons who provided the labelledmaterials used in these intercomparisons:

The USDA/ARS Children's Nutrition Center, Baylor College of Medicine, Houston, USA(Dr. P. Klein), and MSD Canada, Ltd. (Mr. I.I. Lesk) for the 2H- and l8O-labelled watersamples and for the I3C-labelled sodium bicarbonate reference materials;

The Nestlé Research Centre, Vevey, Switzerland (Dr. E. Fern) for the l5N-labelledammonium sulphate reference materials;

The Clinical Research Centre, Harrow, UK (Dr. D. Halliday) for the 13C-labelled UL-glucosereference materials;

The Central Institute of Isotope and Radiation Research, Leipzig, Germany (Prof. H. Faust)for the 15N-labelled urea reference materials;

8. REFERENCES

1. AQCS, Analytical Quality Control Services, IAEA Vienna (issued annually in January).

2. Dybczynski, R., Comparison of the effectiveness of various procedures for therejection of outlying results and assigning consensus values in interlaboratoryprogrammes involving determination of trace elements or radionuclides. Anal. Chim.Acta, 117 (1980) 53-70.

- 6 -

Table 1: 2H in IAEA-302A (Water)

Recommended value: 508.4 per mille (vs VSMOW)95% Confidence interval: 505.5 to 511.3 per mille

No.

1

2

3

4

5

6

7

8

9

10

11

Lab.

Code No.

10

14

18

21

24

32

33

35

36

38

40

Method

Code

A30

A30

A20

A28

A20

A38

A30

A3 8

A30

A2

A30

No. of

Results

3

6

3

4

6

6

5

2

4

1

6

Mean

508.73

511.73

506.33

501.25

505.57

506.28

515.50

509.35

506.77

527.54*

512.53

Standard

Abs %

0.90

0.70

3.51

1.50

1.77

2.71

3.65

0.35

2.36

0.57

Deviation

ReI %

0.20

0.10

0.70

0.30

0.40

0.50

0.70

0.10

0.50

0.10

Lab.

LoD

1.50

1.00

1.40

6.00

2.25

0.97

4.20

1.00

1.20

Table 2: 2H in IAEA-302B (Water)

Recommended value: 996 per mille (vs VSMOW)95% Confidence interval 987 to 1004 per mille

No.

1

2

3

4

5

6

7

8

9

10

Lab.

Code No.

10

14

18

21

24

32

33

36

38

40

Method

Code

A30

A30

A20

A28

A20

A38

A30

A30

A2

A30

No. of

Results

3

6

3

4

6

3

5

4

1

6

Mean

997.40

1007.63

993.00

984.25

981.39

1005.73

1015.60

10C0.10

978.26

994.42

Standard

Abs %

1.31

1.17

7.94

3.30

5.03

4.32

8.59

1.74

4.26

Deviation

ReI %

0.10

0.10

0.80

0.30

0.50

0.40

0.80

0.20

0.40

Lab.

LoD

1.50

1.00

1.40

6.00

2.25

0.97

1.00

1.20

- 7 -

Table 3: Statistical summary of results for 2H samples

Isotope determined:

Material:

Unit:

Number ofreportedresults

Number ofacceptedresults

Laboratoryaverages:

Individualdeterminations :

Laboratoryaverages:


Total range ofLaboratory averages:

Range of acceptedLaboratory averages:

Percentage of outlyingLaboratories:

Overall mean of acceptedLaboratory averages:

Standarddeviation

(S.D.)

Standarderror

(S.E.)

Abs :

ReI %:

Abs:

Rel' %:

Confidence limits for themean of populationfor probability level .95

2H

IAEA-302A

per mille

11

46

10

45

501.25 -527.54

501.25 -515.50

9

508.41

4.08

0.8

1.29

0.3

505.48 -511.33

2H

IAEA-302B

per mille

10

41

10

41

978.26 -1015.60

978.26 -1015.60

0

995.78

12.07

1.2

3.82

0.4

987.15 -1004.41

- 8 -

Figure 1: 2H in IAEA-302À (Water)


«3

O

OLTUERS NOT INCLL1DED:

LAB METHOD MEANCODE CODE

31 Al 327 54

2) 24' 32' IB1 36' 10' 3E

Laboratory code

14' 40' 33

Figure 2: 2H in IAEA-302B (Water)

Recommended value: 996 per mille (vs VSMOW)95% Confidence interval 987 to 1004 per mille

B3 H 3

331"21 18' 40' 10' 36' 32'

Laboratory code

- 9 -

Table 4: 18O in IAEA-304A (Wat^r)


No.

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

Lab.

Code No.

10

14

15

18

21

24

30

32

33

35A

35B

36

38

39

40

Method

Code

A3 7

A3 7

A 37

A27

A27

A27

A2 7

A30

A3 7

A47

A30

A37

A2

A2 7

A37

No. of

Results

2

5

5

2

3

2

5

3

2

3

2

3

1

2

6

Mean

258.24

253.21

249.74

256.05

248.83

251.20

258.77

252.36

252.20

252.53

251.10

252.95

243.34

242.45

251.90

Standard

Abs %

1.15

0.87

0.49

0.07

3.15

0.86

5.62

1.16

0.14

0.38

0.68

0.06

0.10

1.10

Deviation

ReI %

0.40

0.30

0.20

0.00

1.30

0.30

2.20

0.50

0.10

0.10

0.30

0.00

0.00

0.40

Lab.

LoD

0.09

0.10

0.30

0.10

0.60

0.45

1.91

1.20

1.20

0.15

0.30

0.06

Table 5: 18O in IAEA-304B (Water)


NO.

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

Lab.

Code No.

10

14

15

18

21

24

30

32

33

35A

35B

36

38

39

40

Method

Code

A37

A37

A37

A27

A27

A27

A27

A30

A37

A47

A30

A37

A2

A27

A37

No. of

Results

2

5

3

2

3

2

5

3

2

3

2

2

1

2

- 6 .....

Mean

512.33

502.53

496.05

510.60

494.70

502.13

504.48

505.72

502.40

503.03

502.18

505.35

488.14

381.39*

505.68

Standard

Abs %

0.47

0.98

0.39

0.14

6.09

0.43

6.41

0.31

0.28

0.15

1.58

0.40

0.87

0.46 1

Deviation

ReI %

0.10

0.20

0.10

0.00

1.20

0. 10

1.30

0.10

0. 10

0.00

0.30

0.10

0.20

o. io !

Lab.

LoD

0.09

0.10

0.30

0.10

0.60

0.45

1.91

1.20

1 .20

0. 15

0. 30

0.06

- 10-

Table 6: Statistical summary of results for 18O samples

Isotope determined:

Material:

Unit:



Laboratoryaverages :


Laboratoryaverages:

Individualdeterminations:





Standarddeviation

(S.D.)

Standarderror

(S.E.)

Abs:

ReI %:

Abs:

ReI %:


"O

IAEA-304A

per mille

15

4 IS

15

46

242.45 -258.77

242.45 -258.77

0

251.66

4.51

1.8

1.16

0.5

249.16 -254.16

"O

IAEA-304B

per mille

15

43

14

41

381.39 -512.33

488.14 -512.33

7

502.52

6.23

1.2

1.66

0.3

498.93 -506.12

-11 -

Figure 3: 18O in IAEA-304A (Water)


39 38' 21 15' 35B 24' 40 33 32 3 5 H 36' 147 18' 101 3Û

Laboratory code

Figure 4: 18O in IAEA-304B (Water)


'I - -

X j .

O

»3

tO

O

03 _

O

01TLŒR5 NOT INCLUDED.

LAB MTTOODCODE CODE

39 All 311.JP

2 T 15 24 3SB S31 U 35 &

Laboratory code

3 2 1 6 1 1 0 1

- 12-

Table 7: 13C in IAEA-303A (Sodium bicarbonate)

Recommended value: 93.3 per mille (vs VPDB)95% Confidence interval: 91.1 to 95.4 per mille

No.

1

2

3

4

5

6

7

8

9

10

11

Lab.

Code No.

3

7

11

12

15

16

17

24

35

38

40

Method

Code

A40

A4

A20

A20

A20

A30

A4 2

A20

A42

A2

A30

No. Of

Rssults

6

6

6

6

3

5

6

6

3

1

2

Mean

90.26

96.79

96.96

92.41

93.32

94.87

88.11

93.06

107.50*

109.38*

93.47

Standard

Abs %

1.08

0.33

0.34

1.21

0.20

0.63

0.48

1.17

1.17

0.22

Deviation

ReI %

1.20

0.30

0.30

1.30

0.20

0.70

0.50

1.30

1.30

0.20

Lab.

LoD

1.10

0.33

0.03

0.02

0.35

0.15

0.06

0.60

1.65

0.03

Table 8: 13C in IAEA-303B (Sodium bicarbonate)

Recommended value: 466 per mille (vs VPDB)95% Confidence interval: 460 to 472 per mille

No.

1

2

3

4

5

6

7

8

9

10

Lab.

Code No.

3

7

11

12

15

17

24

35

38

40

Method

Code

A40

A4

A20

A20

A20

A42

A20

A42

A2

A30

No. of

Results

6

6

6

6

5

4

3

3

1

2

Mean

459.58

477.17

467.24

466.60

469.45

439.32*

463.03

453.58

503.68*

470.29

Standard

Abs %

3.55

1.17

9.85

5.11

0.44

0.29

6.18

0.97

2.74

Deviation

ReI %

0.80

0.20

2.10

1.10

0.10

0.10

1.30

0.20

0.60

Lab.

LoD

1.10

0.33

0.03

0.02

0.35

0.06

-C.60

1.65

0.03

- 13-

Table 9: 13C in IAEA-309A (UL-glucose)


No.

1

2

3

4

5

6

7

8

9

10

11

12

13

Lab.

Code No.

3

7

12

15

16

17

24

26

33

35

38

40A

4OB

Method

Code

A40

A4

A23

A22

A30

A42

A20

A80

A33

A4 2

A2

A3 3

A33

No. of

Results

6

6

6

4

6

6

6

1

2

6

1

5

3

Mean

95.11

94.97

94.28

82.22*

92.06

94.75

92.04

38.70*

92.95

133.60*

79.43*

93.55

95.40

Standard Deviation

Abs %

0.47

0.13

0.24

1.28

0.45

0.11

0.53

0.21

2.67

0.50

0.38

ReI %

0.50

0.10

0.30

1.60

0.50

0.10

0.60

0.20

2.00

0.50

0.40

Lab.

LoD

1.10

0.16

0.02

0.60

0.60

0.60

1.65

0.05

0.04

Table 10: 13C in IAEA-309B (UL-glucose)


No.

1

2

3

4

5

6

7

8

9

10

11

12

Lab.

Code No.

3

7

12

15

17

24

26

33

35

38

4OA

4OB

Method

Code

A40

A4

A2 3

A22

A42

A20

A80

A33

A42

A2

A3 3

A33

No. of

Results

6

6

4

3

6

6

1

2

6

1

5

4

Mean

544.85

540.55

536.69

529.67

539.19

524.42

81.90*

530.15

528.81

471.04*

5 37.02

541.83

Standard

Abs %

0.55

0.18

3.50

1.31

0.90

1.05

0.78

6.48

3.45

1.06 !

Deviation

ReI %

0.10

0.00

0.70

0.20

0.20

0.20

0.10

1.20

0.60

0.20

Lab.

r.oD

1.10

0.16

0.02

0.60

0.60

Ij

1.65

0.05

0. 04

- 14 -

Table 11: Statistical summary of results for 13C samples

Isotope determined:

Material:

Unit:



Laboratoryaverages:


Laboratoryaverages:






Standarddeviation

(S.D.)

Standarderror

(S.E.)

Abs :

ReI %:

Abs:

ReI %:


13C

IAEA-303A

per mille

11

50

9

46

88.11 -109.38

88.11 -96.96

18

93.25

2.85

3.1

0.95

1

91.06 -95.44

13C

IAEA-303B

per mille

10

42

8

37

439.32 -503.68

453.58 -477.17

20

465.87

7.18

1.5

2.54

0.5

459.86 -471.88

13C

IAEA-309A

per mille

13

58

9

46

38.70 -133.60

92.04 -95.40

31

93.90

1.3

1.4

0.43

0.5

92.90 -94.90

13C

IAEA-309B

per mille

12

50

10

48

81.90 -544.85

524.42 -544.85

17

535.32

6.67

1.2

2.11

0.4

530.55 -540.09

- 15 -

Figure 5: 13C in IAEA-303A (Sodium bicarbonate)


—H I

PE

a*

— j —O6

6

a;

j

Î6

—

b

—

f>3

O

— —

Q

—

Oe

A2

O6

—-

OLTLIERS NOT KCLIDED:.

LAXCODE

Si31

METHODCODE

A 4 :

IC

MEAN

10' 3010(31

Laboratory code

Figure 6: 13C in IAEA-303B (Sodium bicarbonate)

Recommended value: 466 per mille (vs VPDB)95% Confidence interval: 460 to 472 per mille

0t T

- o -Ol-TUOS NOT WCLLTED:

LAB METHOD MlANCODI CODi

A4)A3

Laboratory code

- 16-

Figure 7: 13C in IAEA-309A (UL-glucose)


6

Î01TUXKS NOT P.CLLDED

L A lCODE

MJ lI j

JJ

METHODCODB

AIOj ^

AUA «

MEAK

Jl 'O79 43

1123

U J M

12

Laboratory code

Figure 8: '3C in IAEA-309B (UL-glucose)


_ (H _ O _

OITLIEHS SOT [NCLLDEB- . .

LAl METHOD MEANCODB CODB

AUKl

ToF"

Laboratory code

- 17-

TabSe 12: 15N in IAEA-305A (ammonium sulphate)

Recommended value: 39.8 per mille (vs air)95% Confidence interval: 39.3 to 40.3 per mille

No.

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

Lab.

Code No

1

2

4

5A

SB

6

7

8A

8B

9

11

14

15

16A

16B

17

19

23

24

25

27

28

29A

29B

29C

29D

31

34

35

Method

Code

A42

A4 2

A4 2

A21

A21

A31

A4

A23

A4 2

A42

A31

A31

A21

A4

A31

A42

All

All

A21

A33

A34

A73

A23

A23

B20

B21

B22

Bl

A42

No. Of

Results

6

6

6

5

5

5

6

3

3

6

6

4

5

5

5

5

4

6

3

6

3

5

6

6

5

6

5

6

6

Mean

46.82*

39.05

41.24

38.26

39.52

39.90

40.23

40.83

43.94*

39.55

39.39

39.84

39.41

41.16

39.36

37.84

40.90

38.00

41.04

38.41

41.03

39.92

40.72

24.30*

30.97«

24.30*

38.58

47.14*

41.06

Standard Deviation

Abs %

3.70

0.41

0.23

0.25

0.41

0.57

0.19

0.00

1.58

0.09

0.45

0.09

0.12

0.39

1.34

0.42

3.79

2.06

1.14

0.36

0.90

2.90

0.02

13.36

7.15

13.58

1.58

24.25

2.39

ReI %

7.90

1.10

0.60

0.60

3.00

1.40

0.50

0.00

3.CO

0.20

1.20

0.20

0.30

1.00

3.40

1.10

9.30

5.40

2.80

0.90

2.20

7.30

0.00

55.00

23.10

55.90

4. 10

51.50

5.80

Lab.

LoD

0.0015

0.5200

0.0010

0.0020

0.0020

0.0006

0.3000

0.0001

0.0020

0.3300

0.0001

0.2000

0.3000

0.6000

0.1500

1.0000

0.0030

0.0010

0.6000

0.0003

0.3000

0.3000

0.0200

0/0200

0.0200

0.0003

0.0061

0.0008

- 18-

Table 13: 15N in IAEA-305B (ammonium sulphate)


No.

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

Lab.

Code No.

1

2

4

5A

5B

6

7

8A

8B

9

11

14

15

17

19

23

24

25

27

28

29A

29B

29C

29D

31

34

35

Method

Code

A42

A42

A42

A21

A21

A31

A4

A23

A42

A4 2

A31

A31

A21

A42

All

All

A21

A33

A34

A73

A23

B20

B21

B24

A31

Bl

A42

NO. Of

Results

5

6

6

5

5

5

6

3

3

6

6

4

5

5

5

6

3

6

3

5

6

6

5

6

6

6

6

Mean

381.73

375.30

377.41

373.70

370.90

388.93

379.48

377.92

377.83

368.43

372.83

374.48

376.53

374.70

378.43

369.58

373.37

362.35

380.00

374.80

378.04

340.28*

383.32

337.99*

373.98

365.46

372.92

Standarc

Abs %

3.47

0.37

0.34

0.67

6.12

2.22

0.11

0.16

0.00

1.05

0.74

0.19

0.28

0.45

5.91

0.00

1.36

0.73

1.35

0.84

0.49

20.75

27.68

12.38

4.24

29.53

2.04

Deviation

ReI %

0.90

0.10

0.10

0.20

1.60

0.60

0.00

0.00

0.00

0.30

0.20

0.10

0.10

0.10

1.60

0.00

0.40

0.20

0.40

0.20

0.10

6.10

7.20

3.70

1.10

8.10

0.50

Lab.

LoD

0.0015

0.5200

0.0010

0.0020

0.0020

0.0006

0.3000

0.0001

0.0020

0.3300

0.0001

0.2000

0.3000

1.0000

0.0030

0.0010

0.6000

0.0003

0.3000

0.5000

0.0200

0.0200

0.0200

0.0003

0.0061

0.0008

- 19-

Table 14: 1SN in IAEA-310A (urea)


No.

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

Lab.

Code No.

1

2

3

4

5A

5B

7

8A

8B

9

11

15

16A

16B

17

19

23

24

25

27

28

29A

29B

29C

34

35

37

Method

Code

A42

A42

A40

A4 2

A24

A24

A4

A23

A42

A4 2

A34

A24

A4

A34

A42

All

All

A24

A3 3

A34

A73

A23

B21

B24

Bl

A4 2

B15

No. of

Results

6

6

6

6

5

5

6

3

3

6

6

3

5

5

5

6

6

3

6

3

5

5

5

6

5

6

5

Mean

53.58

47.68

46.86

49.10

46.81

47.74

48.70

48.96

45.77

47.71

66.77*

48.04

49.68

49.30

43.34

39.92

55.82*

48.02

46.09

48.63

43.44

48.94

44.67

48.96

41.38

50.43

85.63*

Standard Deviation

Abs %

3.97

0.17

1.03

0.11

0.36

0.74

0.15

0.16

0.00

0.17

0.40

0.30

0.54

0.29

0.23

6.85

2.83

1.14

0.36

0.67

1.47

0.11

9.61

13.70

24.25

0.77

56.90

ReI %

7.40

0.40

2.20

0.20

0.80

1.50

0.30

0.30

0.00

0.40

0.60

0.60

1.10

0.60

0.50

17.20

5.10

2.40

0.80

1.40

3.40

0.20

21.50

28.00

58.60

1.50

30.60

Lab.

LoD

0.0015

0.9600

0.0010

0.0005

0.0020

0.0020

0.3500

0.0001

0.0020

0.3300

0.0001

0.3000

0.6000

0.1500

1.0000

0.0030

0.0010

0.6000

0.0002

0.3000

0.5000

0.0200

0.0200

0.0061

0.0008

- 2 0 -

Table 15: 15N in IAEA-310B (urea)


No.

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

Lab.

Code No

1

2

3

4

5A

5B

7

8A

8B

9

11

15

16A

16B

17

19

23

24

25

27

28

29A

29B

29C

34

35

37

Method

Code

A42

A42

A40

A4 2

A24

A24

A4

A23

A4 2

A42

A34

AZ 4

A4

A34

A42

All

A14

A24

A33

A34

A73

A23

B21

B24

Bl

A4 2

B15

No. of

Results

6

6

6

6

5

5

6

3

3

6

6

3

5

5

5

6

6

3

6

4

5

3

5

6

6

6

5

Mean

243.03

242.75

247.42

244.63

244.08

245.56

247.45

246.28

243.26

240.84

243.93

244.83

245.08

243.76

243.22

232.87*

246.00

242.53

235.07*

242.45

245.60

246.31

244.90

228.62*

221.31*

246.46

246.03*

Standard Deviation

Abs %

3.88

0.53

0.66

0.17

0.67

0.66

0.10

0.00

0.00

0.86

0.26

0.22

0.55

0.87

0.37

10.09

0.00

0.64

0.94

1.88

1.95

0.59

16.76

18.34

44.69

3.04

100.11

ReI %

1.60

0.20

0.30

0.10

0.30

0.30

0.00

0.00

0.00

0.40

0.10

0.10

0.20

0.40

0.20

4.30

0.00

0.30

0.40

0.80

0.80

0.20

6.80

8.00

20.20

1.20

40.70

Lab.

LoD

0.0015

0.9600

0.0010

0.0005

0.0020

0.0020

0.3500

0.0001

0.0020

0.3300

0.0001

0.3000

0.6000

0.1500

1.0000

0.0030

0.0010

0.6000

0.0003

0.3000

0.5000

0.0200

0.0200

0.0061

0.0008

* not included in plot because of large standard deviation

-21 -

Table 16: 15N in IAEÂ-311 (ammonium sulphate)

Recommended value: 2.05 atom %95% Confidence interval: 2.03 to 2.06 atom %

No.

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

Lab.

Code No.

1

2

3

4

5A

5B

6

7

8A

8B

11

13

14

15

17

19

20

22A

22B

23

24

25

28

29A

29B

29C

31

34

35

Method

Code

A42

A42

A40

A42

A21

A21

A31

A4

A23

A4 2

B21

BlO

A31

A21

A42

All

B14

BIl

B14

All

A21

A33

A73

B20

B21

B24

A31

Bl

A42

No. of

Results

6

6

6

6

5

5

4

6

3

3

6

5

4

6

5

6

2

1

6

6

3

6

5

6

5

6

5

6

6

Mean

2.06

2.05

2.09

2.06

2.05

2.06

2.12

2.07

2.06

2.06

2.04

1.64*

2.04

2.08

2.06

2.05

2.01

2.08

2.08

2.07

1.99

1.99

2.09

2.00

2.07

1.96

2.02

2.00

2.05

Standard Deviation

Abs %

0.01

0.00

0.00

0.00

0.00

0.00

0.01

0.00

0.00

0.00

0.01

0.01

0.00

0.00

0.00

0.02

0.02

0.01

0.01

0.01

0.00

0.01

0.01

0.01

0.01

0.01

0.01

0.01

ReI %

0.40

0.10

0.10

0.00

0.10

0.00

0.40

0.00

0.00

0.00

0.50

0.60

0.20

0.10

0.00

1.20

0.90

0.50

0.60

0.40

0.10

0.70

0.70

0.30

0.40

0.50

0.70

0. 70

Lab.

LoD

0.0015

0.0002

0.0010

0.0020

0.0020

0.0020

0.0240

0.3500

0.0001

0.0020

0.0360

0.1381

0.0040

0.1000

0.0004

0.0030

0.0020

0.0300

0.0120

0.0010

0.0003

0.0001

0.0003

0.0200

0.O200

0.0200

0.0003

0.0003

0.0008

- 2 2 -

Table 17: Statistical summary of results for 1SN samples

Isotope determined:

Material:

Unit:



Laboratoryaverages:


Laboratoryaverages:

Individualdeterminations:





Standarddeviation

(S.D.)

Standarderror

(S.E.)

Abs:

ReI %:

Abs:

ReI %:


15N

IAEA-305A

per mille

29

148

23

116

24.30 -47.14

37.84 -41.24

21

39.79

1.09

2.7

0.23

0.6

39.32 -40.26

15N

IAEA-3O5B

per mille

27

13S

25

127

337.99 -388.93

362.35 -388.93

7

375.3

5.60

1.5

1.12

0.3

372.99 -377.61

'5N

IAEA-310A

per mille

27

137

24

120

39.92 -185.63

39.92 -53.58

11

47.24 .

3.00

6.3

0.61

1.3

45.97 -48.51

15N

IAEA-310B

per mille

27

137

23

113

221.31 -247.45

240.84 -247.45

15

244.63

1.73

0.7

0.36

0.1

243.88 -245.37

15N

IAEA-311

atom %

29

145

28

140

1.64 -2.12

1.96 -2.12

3

2.05

0.04

1.8

0.01

0.3

2.03 -2.06

- 2 3 -

Figure 9: 15N in IAEA-305A (ammonium sulphate)


S 6

flî »J - 5 - ' - ' - 1O 6

GlTUEtS NOT INCLUDED!

LAlCODB

2 »29D2KKI

METHODCODB

(20«24S21A42A42•J

MEAN

24J024J0JO »743 944« (247 14

171 SR23 2; i l 5B M 28 29P 19 24

Laboratory code

r351

160

Figure 10: ISN in IAEA-305B (ammonium sulphate)


T

s?

O l T U n S NOT INCLVDCD:

LA* UEDIOD MIANCODl CODS

29D fc« 33Î 99» • UO 340.21

1 ' 91 ' SB '55 ' 5R 1i4 1 '28- 1I!34 23 11 24 31 17 2

i 8 B Z4 8 0 27 29C

Laboratory code

- 2 4 -

Figure 11: 15N in IAEA-310A (urea)


- is1

28

Laboratory code

Figure 12: 15N in IAEA-310B (urea)


6 i 3 IRESULTS NOT INCLUDED:

1 Be 1 H 1 ^ r

/ I6B 50 15

Laboratory code

•^n;

LABCODE

34!9C192357

METHODCODE

BI•24AllAMBlS

MEAN

221Jl221.62232 17235.072« 03

275b 2 i

1 6(H 35

- 2 5 -

îigure 13: 15N in IAEA-311 (ammonium sulphate)

Recommended value: 2.05 atom %95% Confidence interval: 2.03 to 2.06 atom %

. À ? ? ? O

_ _ _ _ _ — y — _ : _ _ _ 6 — —

i 6

95

OLTUESS 1JOT INCLUDED:

LAI MEHtOD MEANCODS CODE

24 29fl 2^ 35 1 T91 ' 5B ' 8R ' I 1 2 3 22B 22R ?b '

5fl 2 17 4 8B 2=3 7 15 3 6

Laboratory code

- 2 6 -

Table 18: Overview of all recommended values

Sample

302A

302B

303A

303B

304A

304B

305A

305B

309A

309B

310A

310B

311

Isotope

2H2H13C13C18O18O15N15N13C13C15N15N15N

Enrichment*per mille

508.4

996

93.3

466

251.7

502.5

39.8

375.3

93.9

535.3

47.2

244.6

2.05

95%Confidence Interval

505.5-511.3

987 - 1004

91.1 -95.4

460 - 472

249.2 - 254.2

498.9-506.1

39.3 - 40.3

373.0 - 377.6

92.9 - 94.9

530.6-540.1

46.0 - 48.5

243.9 - 245.4

2.03 - 2.06

VS

VSMOW

VSMOW

VPDB

VPDB

VSMOW

VSMOW

air

air

VPDB

VPDB

air

air

* All values as per mille, except for IAEA-311, which is as atom percent

Annex 1

M E T H O D C O D E S

A - GROUPOFANALYTICALINSTRUMENTSÛ -• INDIVIDUALSYSTEMFORISOTOPICANALYSISÛ -+ SAMPLE PREPARATION METHOD IDENTIFICATION *

A mass spectrometryA 1 conventional routine mass spectrometry (MS)A 2 conventional high precision MS (dual inlet, dual (triple) collector)A 3 modern isotope ratio MS (IRMS)A 4 on line EA/MS (EA: elemental analyser)A 5 quadrupole MSA 6 chemical ionization/MSA 7 IRM-GCMS (gas chromatographic effluent is catalytically combusted

to N2, CO2 or H2O prior to entering a modified IRMS)A 8 SIM-GCMS (isotope enrichment is determined from the ion produced

by the entire derivatized molecule or from a suitable fragment ion)

B emission spectrometryB 1 optical emission spectrometry (ES), conventional procedure by NOI-5 type

instrumentsB 2 automated ESB 3 on line EA/ES (EA: elemental analyser)

C other or unspecified methodsC 1 NMRC 2 ESRC 3 infrared absorption spectroscopy

D special micromethods

* CODES FOR SAMPLE PREPARATION METHODS(includes codes for 2H, 13C, 15N and 18O)

1 RITTENBERG preparation (hypobromite)2 DUMAS preparation I (combustion, cyclic method)3 DUMAS preparation II (combustion, ampoule method)4 KJELDAHL digestion plus RITTENBERG5 KJELDAHL digestion plus DUMAS I6 KJELDAHL digestion plus DUMAS II7 CO2 - water exchange8 reduction of water to H2 over uranium metal9 reduction of water to H2 over chromiumO other

- 2 9 -

LIST OF PARTICIPANTS

Annex 2

Dr. Murray UNKOWICHSchool of Agriculture and ForestryUniversity of MelbournePARKVILLE, Victoria 3052Australia

Helga AXMANNInternational Atomic Energy AgencyLaboratory SeibersdorfP.O. Box 100A-1400 VIENNAAustria

Dr. W. PAPESCHAbt. IsotopengeophysikB V F A ArsenalPostfach 8A-1031 VIENNAAustria

Dr. F. PICHELMAYEROesterreichiscb.es Forschungs-Zentrum Seibersdorf Ges.m.b. H.A-2444 SEIBERSDORFAustria

Dr. S.U. PATWARYSoil Science DivisionB I M AP.O. Box 4MYMENSINGHBangladesh

Prof. Dr. Y. GHOOSLabo Gastro-Ente.'ologie E462Universitaire ZiekenhuisenSt. Rafael - GaslhuisbergHerestraat 49B-3000 LEUVl-NBelgium

Mr. Clive T. FIGUEIREDOSoil Science DepartmentRoom 350, Earth Sciences BuildingUniversity of AlbertaEDMONTON, Alberta T6G 2E3Canada

Dr. Alberto POLLASTRI JORDANEnvironmental Isotope LaboratoryComision Chilena de Energia NuclearAmunategui 95Casilla 188-DSANTIAGO de CHILEChile

Dr. DE QIU JINDepartment of ChemistryPeking UniversityBEIJINGPeople's Republic of China

Dr. WANG ZHI DONGInstitute for Application ofAtomic EnergyChinese Academy of Agricultural ScienceP.O. Box 5109BEUING 100094People's Republic of China

Dr. G. GUlRAUDDB/SRACommissariat a l'Energie AtomiqueCentre d'Etudes Nucléaires de CadaracheF-131I5 SAINT-PAUL-LEZ-DURANCEFrance

Dr. B. MARYI N R IStation d'AgronomieB.P. 101F-O20O4 LAON CedexFrance

- 3 0 -

Mme. Christiane PACHIAUDIINSERM U.197Faculte de Medicine Alexis CarrelRue G. ParadinF-69372 LYON Cedex 08France

Dr. H. FAUSTZentralinstitut fuer Isotopen-und StrahlenforschungPermoserstrasse 15D-O7050 LEIPZIGGermany

Dr. Gerhard GEBAUERLehrstuhl filer PflanzenoekologieUniversitär BayreuthUniversitaetstr. 30D-W8580 BAYREUTHGermany

Dr. K. KRAWIELITZKIForschungszentrum f. TierproduktionBereich Tieremaerung 'Oskar Kellner"Dummerstorf-Rostock der AdiJustus-von-Liebig-WegPostfach 27-01/02D-O 2500 ROSTOCK 1Germany

Dr. A. KULLMANNInstitut fuer Pflanzenbauund PflanzenzuechtingOlshausenstrasse 40D-W23OO KIEL 1Germany

Dr. F. VIRGILIIstituto Nazionale della NutrizioneVia Ardeatina 5461-00179 ROMAItaly

Dr. T. YONEYAMADept. of Soils and FertilizersNational Agriculture ResearchCentreKannondai 3-1-1TSUKUBA. IBARAKI 305Japan

Dr. Mahendra P. VERMADepartamento de GeotermiaInterior Internado PalmiraInstituto de Investigaciones EléctricasApartado Postal 47562000 CUERNAVACA, MorelosMexico

Dr. M. Ishaq SAJJADPakistan Institute of NuclearScience and TechnologyP.O. NiloreRAWALPINDIPakistan

Prof. Dr. Wieslav BARE)Department of Animal PhysiologyWarsaw Agricultural UniversityUI. Nowoursynowska 166PL-02-766 WARSAWPoland

Dr. T. FLORKOWSKIInstitute of Nuclear Physicsand TechniquesAcademy of Mining &. MetallurgyAl. Mickiewicza 30PL-30-059 KRAKOWPoland

Dr. N. PALIBRODAInstitute of Isotopie andMolecular TechnologyP.O. Box 700R-3400 CLUJ-NAPOCA 5Romania

Mrs. M.C.S. SENEVIRATNEAtomic Energy Authority1st floor, Ceramics Building696 Galle RoadCOLOMBIA 03Sri Lanka

Dr. Kevin ACHESONResearch CentreNESTLÉAvenue Nestlé 55CH-1800 VEVEYSwitzerland

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Dr. Steven BROOKESEuropa Scientific Ltd.Scope HouseWeston RoadCREWE, Cheshire CWlUnited Kingdom

IDD

Mr. P. JOHNSONBureau of Stable Isotope AnalysisIS Brook Lane Business CentreBRENTFORD, Middlesex TW8 OPPUnited Kingdom

Dr. Peter J. GOODMANAgriculture & Food Res. CouncilInstitute for Grassland and Animal ProductionWelsh Plant Breeding Station, Plas GogerddanABERYSTWYTH, Dyfed SY23 3EB, WALESUnited Kingdom

Dr. Thomas PRESTONScottish Universities Researchand Reactor CentreEAST KILBRIDEGLASGOW, Scotland G75 OQUUnited Kingdom

Drs. G.W. ROBERTSON & W. STEINChemistry DepartmentScottish Crop Research InstituteInvergowrieDUNDEE, Scotland DD2 5DAUnited Kingdom

Dr. R.J. STEVENSFood and AgriculturalChemistryResearch DivisionDepartment of AgricultureNewforge LaneBELFAST, Northern Ireland BT9 5PXUnited Kingdom

Prof.Dr. A. WILDDepartment of Soil ScienceUniversity of ReadingLondon RoadREADING, Berks. RGl 5AQUnited Kingdom

Patrick MOYNAFacultad de QuimicaAv. General Flores 2124MONTEVIDEOUruguay

Dr. Kenneth R. KELLEYAgricultural Research BranchF134 NFDCTennessee Valley AuthorityMUSCLE SHOALS, Alabama 35660United Stales of America

Prof.Dr. C. Lawrence KIENDivision of NutritionChildren's Hospital, W209Research Foundation700 Children's DriveCOLUMBUS, OH. 43205United States of America

Prof. R. MULVANEYDepartment of AgronomyCollege of AgricultureUniversity of Illinois at Urhana-ChampaignS-508 Turner Hall1102 South Goodwin RoadURBANA, IL 61801United States of America

Dr. Dale SCHOELLERDepartment of Medicine - Box 223University of Chicago5841 S. Maryland Ave.CHICAGO, IL 60637United States of America

Prof. Dr. Robert WOLFEMetabolism UnitShriners Burns InstituteUniversity of TexasMedical Branch610 Texas AvenueGALVESTON, TX 77550United States of America

Dr. William W. WONGStable Isotope LaboratoryChildren's NutritionResearch Center1100 Bates StreetHOUSTON, TX 77030United States of America

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