1

Programa Programa MERCOSUR MERCOSUR

de de Comparaciones Comparaciones InterlaboratoriInterlaboratori

osos

2

Hola, buenas dias soy

Miguel Scheutwinkel

3

Hallo, thank you for coming.

4

Programa

• 09.00 – 10.00 Presentación del desempeño del proyecto de los ensayos interlaboratorios por el OA nacional

• 10.00 – 11.00 Introducción a la segunda ronda (Dr. Scheutwinkel), Criterios de evaluación, metódos de referencia, estadística, valores de orientación

• 11.00 – 11.30 Pausa de café

• 11.30 – 13.00 Fechas y organización del PT (Dr. Scheutwinkel) Discusión

• 13.00 – 14.30 Pausa de almuerzo

• 14.30 – 16.00 Presentación y evaluación de los resultados de la ronda intermedia de suero de leche en polvo (experto nacional a designar por los OAs)

5

Secunda Ronda in Alimentos

BMZ

PTB - LATU

ONACGCREOUA

Luis Mussio

PT- Provider / Resp. de Evaluación

OAA

Material de Referencia Laboratorio de Referencia

MUESTRAAlimentos

LABORATORIOS

CLIENTE / INDUSTRIA

Rol de NMI

Chile

7

MuvaMuva

Dr. Leist and his teamDr. Leist and his team Dr. Leist and his teamDr. Leist and his team

Changes in organization of PT Rounds Changes in organization of PT Rounds

Before Now

Statistical evaluation of results

BasisISO-Guide 43-1 Statistical analysis

Referencevalue

Standarddeviation

of PT

Consensus value Defined by provider

Condition:3x greater than

variation from material!

Limits for successful participation

successful

not successfulquestionable

ISO 13528 ISO 5725 ISO 13528 ISO 5725

9

After long discussions it was decided to follow the European Approach in addition with South American results.

Means:

The best estimate of the “true value” is based on the value, obtained by those laboratories applying the reference method.

And in addition only South American results, same as was applied in the intermediate round.

80 Labs 80 Labs

10

n

iationofRangeIntervalConfidence

var___

Uncertainty of reference value:

The higher value of the reference method´s confidence interval (Europe) or of the material´s uncertainty will be attributed to the reference value.

Range of variation of best estimate of the “true value”:

torstudentfacestimatebestofSD

tsiationofRange

*___

*%)95_(var__

11

U = confidence interval at 95 % confidence level

t = factor t de Students = desviación estándar of best estimate of true valuen = número de ensayos

nst

U

Uncertainty of the best estimate of the “true value”:

Uncertainty of reference value:

The higher value of the - reference method´s confidence interval (Europe) or of- the material´s uncertainty will be attributed to the reference value.

Stastistical evaluations will be based on „true values“ achieved by those laboratories using the reference method after the Grubbs

outlier test. Laboratories will receive values for:

Stastistical evaluations will be based on „true values“ achieved by those laboratories using the reference method after the Grubbs

outlier test. Laboratories will receive values for:

z‘-score z-score CRD-value

z‘-score z-score CRD-value

Calculation of difference of Laboratory mean – Mean of all values = di

Calculation of buffer size = di / standard deviation

by comparing buffer size with Grubbs-values (dependent on number of participants n) an outlier exists, if the buffer size is

bigger than the Grubbs-value.

The results are acceptable, if the buffer size is smaller than the Grubbs-value.

The Grubbs-test will be repeated until no outliers are detected anymore.

Grubbs outlier testGrubbs outlier test

14

)(´

22mr uu

XreflabXlabz

Xlab = laboratory valueXreflab = best estimate for the true value (EU oe SA)ur = SD of reflabs (EU or SA) um = standard uncertainty of the material

The z‘-score gives the difference of the laboratory result to the mean of all „reflabs“ in units of standard deviations taking the standard deviation of the material and the standard deviation of testing values of the applied reference method in this ILC into account.

The z‘-score gives the difference of the laboratory result to the mean of all „reflabs“ in units of standard deviations taking the standard deviation of the material and the standard deviation of testing values of the applied reference method in this ILC into account.

z‘-scorez‘-score

The z´-score is a performance criterion for the laboratory (acc. to ISO 13528 Statistical methods for use in proficiency testing by interlaboratory comparison).

It is calculated by dividing the difference between laboratory mean and the best estimate of the true value (reference value from the actual PT-scheme) by the square root of the sum of the squared standard deviation of the material and the squared standard deviation of testing values of the applied reference method.

Performance is questionable for (absolute) z’-scores between 2 and 3 and unsatisfactory for absolute values exceeding 3.

z‘-score z‘-score

16

Normalverteilung Incertidumbre de medición y distribución normalIncertidumbre de medición y distribución normalIncertidumbre de medición y distribución normalIncertidumbre de medición y distribución normal

Example for z´-score calculation in determination of fat:

Xlab = laboratory value = 0,86 %

Xref = mean of laboratory having applied the reference method (EU or SA) = 0,78 % ur = standard deviation of reference labs (EU or SA) = 0,11 %

um = standard uncertainty of the material = 0,015 %

7,0015,011,0

78,086,0´

22

z

2

18

2)(*

1

1

ximn

s

s

mxz lab

m = mean value of all labs

xi = result of the individual lab

s = standard deviation of all labs after outlier test

Smet = SR of reference method

z-scorez-score

The z-score gives the difference of the laboratory result to the mean of all laboratories in units of standard deviations.

The z-score gives the difference of the laboratory result to the mean of all laboratories in units of standard deviations.

Tabla 1, valores utilizados para el cálculo de Z y Z´Las unidades de la tabla corresponden a las unidades utilizadas en los informes.

MuestraValor Ref EU STD EU Valor Ref SA STD SA u material R S(R)

Grasa 1 0.78 0.11 0.86 0.31 0.03 0.2 0.071

2 1.97 0.07 1.75 0.60 0.06

Proteína 1 13.56 0.17 13.43 0.42 0.04 1.6 0.57

2 30.35 0.39 29.85 1.3 0.3

Lactosa 1 78.12 2.01 77.71 1.68 0.19 0.06 x WL 0.021 x WL

2 48.88 3.3 49.01 4.4 0.19

Ceniza 1 3.38 0.06 3.43 0.08 0.02 0.41 0.14

2 8.42 0.11 8.45 0.17 0.05

Nitrato 1 12.38 4.5 0.30 17 6.01

2 33.02 11.81

Lactico (IDF 69- B)

1 500.3 42.4 16.6 <100 = 15>100= 0.2 x Wlac

6.570.071 x Wlac

2 1002.3 89.1 28.6

Materia Seca (IDF 26 A- 1993)

1 98.01 0.09 98.09 0.27 0.035 0.4 0.14

2 96.07 0.17 96.25 0.66 0.045

CRD-value CRD-value

(method) CRD_

value true_ the_of_ estimate_ best_ -mean _laboratory

valueCRD

2707,0

22 rRCRD

CRD-value < 1 = laboratory is satisfying

CRD-value > 1 = laboratory is not satisfying CRD-value < 1 = laboratory is satisfying

CRD-value > 1 = laboratory is not satisfying

21

New ReferenciaNew Referencia

Eurolab Technical Report No. 1/2007 (March 2007)Measurement uncertainty revisited –

Alternative approaches to uncertainty evaluationwww.eurolab.org

Eurolab Technical Report No. 1/2007 (March 2007)Measurement uncertainty revisited –

Alternative approaches to uncertainty evaluationwww.eurolab.org

22

23

General information about skimmed milk powder

General information about skimmed milk powder

Moisture: max. 4 %

Ash: 5 – 10 %

Fat: max. 1 %

Protein: 30 – 50 %

Lactose: 40 – 50 %

24

General information about non-defatted milk powder

General information about non-defatted milk powder

Moisture: max. 4 %

Ash: 5 – 10 %

Fat: 25 - 35 %

Protein: 25 – 35 %

Lactose: 30 – 40 %

Parameter Method r R s R CRD

Fat

Low Fat MPHigh Fat MP

IDF 9C:1987

0,2 %0,1 %

0,3 %0,2 %

0,106 %0,071 %

0,187 %0,132 %

Dry matter102 °C

IDF 26A:1993 0,2 % 0,4 % 0,141 % 0,265 %

Protein (Factor 7,5)

§ 64 LFGBL 01.00-10/1

0,3 % 0,8 % 0,283 % 0,545 %

Ash § 64 LFGB L 01.00-77 entspr. DIN 10477

0,06 % 0,14 % 0,049 % 0,094 %

Reference methodsReference methods Dr. Leist, 04.07.2007

Dr. Leist, 04.07.2007

Parameter Method r R s R CRD

Lactose (enzymatic)

§ 64 LFGBL 01.00-17

„True value“ x 0,05

„True value“ x 0,06

R 2,83

Lactic acid (enzymatic)

IDF 69B 10 mg/100 g 15 mg/100 g 5,3 mg/100 g

9,354 mg/ 100 g

Nitrat (Cd-reduction)

DIN EN ISO 14673-1

3 mg/kg 8 mg/kg 2,827 mg/kg

5,454 mg/ kg

Reference methodsReference methods Dr. Leist, 04.07.2007

Dr. Leist, 04.07.2007

27© IFC GmbH

Accion Fecha

Information of sample delivery from DRRR to ABs and laboratories

ca. 23.08.2007

Start of PT 10.09.07

Sending the results by the laboratories

28.09.07

Evaluation of results

- by DRRR

- by OAs

31.10.2007

31.12.2007

Time schedule

28

Training idea:Communication technology,

what‘s the problem?

Because of elegant cable technology the structure of the network can be

easily explained to anybody.

29

Training idea: Communication technology, what‘s the problem?

The precise documentation of each communication line ensures the safe, fast and

confidential access to everybody connected to the

system.

The massive construction of coverage avoids any

manipulation of the sensible technology.

30

The clear and systematic approach

seems to be oversized but in any case of emergency

this is a real must.

Because of precise overview there is always one hand to

smoke a cigarette.

Training idea: Communication technology, what‘s the problem?

31

Muchas graciasMuchas gracias por su atención !!!por su atención !!!

32

Proyecto: Metrologia Química

Which methods are the reference methods ....?

33

Determination of Water Content,IDF 26A:1993

Determination of Water Content,IDF 26A:1993

1. Heat uncovered dish and its lid in the oven at 102 + 2 °C for 1 h

2. Cool down in desiccator and weigh to the nearest of 0.1 mg

3. Weigh 1 – 3 g whey powder into the dish to the nearest of 0.1 mg

4. Place it in the oven for 2 h at 102 + 2 °C

5. Cool down the dish and weigh to the nearest of 0.1 mg

7. Repeat heating until constant weight (< 0.5 mg to previous weight)

Repeatability: Absolute difference between the results of two single determinations shall not exceed 0.2 g of water per 100 g of product. Reproducibility: The absolute difference between the results of two single determinations, found out by different operators shall not exceed 0.4 g per 100 g product

34

Determination of Ash Content,IDF 27:1964

Determination of Ash Content,IDF 27:1964

1. Heat the platinum or silica dish in the furnace at 500°C for 30 min

2. Cool down in desiccator and weigh to the nearest of 0.1 mg

3. Weigh 2 – 2.5 g whey powder into the dish to the nearest of 0.1 mg

4. Cover wish ashless filter and start ashing using bunsen burner

5. Ashing of content in the dish at 500°C (max. 550°C)

6. Cool down the dish and weigh to the nearest of 0.1 mg

7. Repeat heating in the furnace for 15 min until constant weight

Repeatability: Absolute difference between the results of two single determinations shall not exceed 0.15 % of ash.

35

Determination of Fat Content,(Röse Gottlieb), IDF 9C:1987

Determination of Fat Content,(Röse Gottlieb), IDF 9C:1987

1. After homogeneition about 1.5 g of dried whey (nearest to 1 mg) transferred to fat-extraction flask (Mojonnier type)

2. Prepare a blank test, instead of dried whey take 10 ml water

3. Prepare fat-collecting vessels: drying of vessels, add a few boiling aids, heating at 102 + 2°C for 1 h, cooling down and weigh to the nearest of 0.1 mg.

4. Add 10 ml water at 65 + 5°C to wash the test portion into the small

bulb of the flasks until the product is completely dispersed.

5. Add 2 ml 25% ammonia, mixing

6. Heat the flask at 65 + 5°Cin the water bath, occasionally shaking.

7. Cooling down to room temperature

36

8. Add 10 ml EtOH, at least 94% (v/v), mix gently

9. Add two drops of Congo red solution (1 g , dilution to 100 ml)

10. Add 25 ml diethyl ether, shaking vigorously avoiding emulsions

11. Transfer organic layer into fat-collecting vessel by decantation

12. Add 25 ml light petroleum (boiling point 30-60°C)

13. Shaking gently and then centrifuge the flask (500– 600 rpm)

14. Allow the closed flask to stand for at least 30 min (separation of

the organic supernatant layer has to be clear and separated

from the aqueous layer (if necessary cool the flask

15. Rinsing of organic layer to fat-collecting vessel, adding gently

some water to raise the aqueous layer and transfer again

organic layer into fat-collecting vessel by decantation

37

16. Rinse the outside of the extraction flask with some mixed

solvent, collecting the rinsings in the fat-collecting vessel

17. If desired, solvent parts may be removed from the vessel by

evaporation etc.

18. Add 5 ml ethanol to the rests in extraction flask

19. Carry out a second extraction by repeating steps 10 to 16

20. Carry out a third extraction (without addition of ethanol)

by repeating steps 10 to 16

21. Remove solvents from fat-collecting vessel as completely

possible (evaporation, destillation)

22. Heat fat-collecting vessel for 1 hour at 102 + 2°C, allow to cool

23. Weigh to the nearest of 0.1 mg.

24. Repeat the heating for checking removal of solvents

38

Determination of Protein Content,IDF 20B:1993, IDF 20:2001, ISO 8968-1

Determination of Protein Content,IDF 20B:1993, IDF 20:2001, ISO 8968-1

Determination of nitrogen using Kjeldahl method

Calculation of protein, please use

Protein = Nitrogen x 6.38

It must be clarified with Dr. Leist which factor shall be used.

39

Determination of Lactic Acid and Lactates,IDF 69B:1987, IDF 79-1 and IDF 79-2:2002

ISO 5765-1 and ISO 5765-2:2002

Determination of Lactic Acid and Lactates,IDF 69B:1987, IDF 79-1 and IDF 79-2:2002

ISO 5765-1 and ISO 5765-2:2002

Both determination are based on enzymatic reactions:

ISO 5765-1 IDF 79-1: Utilizes the glucose moiety of the lactose

ISO 5765-2 IDF 79-2: Utilizes the galactose moiety of the lactose

Please look at GLP requirements in the Annex A

40

Determination of Nitrate and Nitrate,ISO 14673 IDF 189 with Parts 1 to 3

Determination of Nitrate and Nitrate,ISO 14673 IDF 189 with Parts 1 to 3

Determinations are based on spectrophotometric determinations of nitrite:

ISO 14673-1 IDF 189-1:2005 “Method using cadmium reduction and spectrometry”

ISO 14673-2 IDF 189-2:2005 “Method using segmented flow analysis (Routine method)

ISO 14673-3 IDF 189-3:2005 “Method using cadmium reduction and flow injection analysis with in-line dialysis (Routine method)

Please take care about repeatability and reprodicibility requirements in standards.

41

42

43

¿Están listos para una conferencia?