1 Programa MERCOSUR de Comparaciones Interlaboratorios.
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Transcript of 1 Programa MERCOSUR de Comparaciones Interlaboratorios.
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Programa Programa MERCOSUR MERCOSUR
de de Comparaciones Comparaciones InterlaboratoriInterlaboratori
osos
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Hola, buenas dias soy
Miguel Scheutwinkel
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Hallo, thank you for coming.
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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)
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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
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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
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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
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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__
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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
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)(´
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
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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´
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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
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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
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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 %
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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
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Training idea:Communication technology,
what‘s the problem?
Because of elegant cable technology the structure of the network can be
easily explained to anybody.
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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.
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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?
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Muchas graciasMuchas gracias por su atención !!!por su atención !!!
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Proyecto: Metrologia Química
Which methods are the reference methods ....?
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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
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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.
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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
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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
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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
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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.
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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
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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.
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