Reference M aterialsReference M aterialsProgram in CEN AMProgram in CEN AM

Rocio ArvizuRocio ArvizuResearch ChemistResearch Chemist

Centro Centro NacionalNacional de de MetrologíaMetrologíaMéxicoMéxico

Advance School in Metrology in ChemistryAdvance School in Metrology in ChemistryINMETRO INMETRO November 2003November 2003

CENAMCENAM

GENERAL DIRECTORGENERAL DIRECTORDir. Technologic ServicesDir. Technologic ServicesDir. AdministrationDir. Administration

Dir. Mechanical M.Dir. Mechanical M. Dir. M. of MaterialsDir. M. of Materials Dir. Physical M. Dir. Physical M. Dir. Electrical M. Dir. Electrical M.

Mass

Pressure and Force

Electromagnetism

Inorganic Mat Optic and Radiometry

Organic Mat.

Time and Frequency

Flow and Volume

Length

Ceramics Mat.

ThermometryAcoustic and Vibrations

kg

K

cd s

A

molm

Principal Activities in Metrology of MaterialsPrincipal Activities in Metrology of Materials

♦ To Develop and Maintain National StandardsPrimary MethodsCRM

Primary methodsUsing at least two independent methods

♦ To Contribute to the Development of NationalMeasurement System

Reference LaboratoriesPTs

♦ To Provide Metrological Services

Documents of Quality Assurance of CENAMDocuments of Quality Assurance of CENAMrelated with Traceabilityrelated with Traceability

♦ 100-AC-P.1.2.2 Vision of CENAM and 100-AC-P.1.2.4 Vision-Success Factors

“International and National high level scientific and technologicalorganization in the field of Metrology”

“Origin of traceability of measurements in Mexico”

♦ 100-AC-P.1.2.6 Development Plan 2000 – 2006“…maintain the national standards according to the new technology ofmeasurement in order to be the origin of traceability…”

“…all measurements are related with use of SI units and then comparable withmeasurements of the same quantity made in any place…”

TRACEABILITYTRACEABILITY

REFERENCE STANDARD

WORKING STANDARS

MEASUREMENTINSTRUMENT

FIELD LABORATORY

uncertainty

NATIONAL STANDARD

REFERENCE STANDARD

WORKING STANDARD

CENAM

NATIONAL STANDARDS

NMIs

BIPMCIPM-MRA (COMPARABILITY)

Recognized traceability to national standards of other countries

REFERENCE STANDARD

WORKING STANDARD

SECONDARYLABORATORY

Policy of TraceabilityPolicy of TraceabilityMetrology of MaterialsMetrology of Materials

♦ 600-AC-PL.006 Policies of Traceability in the Certification ofReference Materials

To establish the policy of traceability for values expressed in the certificates ofReference Materials.

To assure that all values as a result of any measurement will be traceable to the SIunits

Applicable to all chemical measurements, in order to make them harmonic withuncertainty estimation; according to following policies:

100-AC.P 2.3.10 Policy for uncertainty estimation,600-AC.PL.08 Declaration of uncertainty for certification of reference materials,600-AC.PL.14 Combination of Measurement results and uncertainties in reference materialcertification600-AC. PL.21 Acceptance criteria of the certified value and uncertainty.

It has been adopted the scheme of traceability proposed by W. Richter and G. Dubeand the recommendations issued by the CCQM of BIPM.

FIELD MEASUREMENTS

SI UNITS

Primary Methods

CRM

Primary Methods

RSM RL/ RM

Primary Methods

Metrology, 1997, 34W.Richter y G. Dube

Primary Methods

Practical ways to establish traceabilityPractical ways to establish traceability

Reference Materials

Simple Matrix Certified Reference Materials

Simple Matrix Certified Reference Materials

Transfer MethodsTransfer Methods

Transfer Methods Transfer Methods

PrimaryReference Materials

PrimaryReference Materials

Primary Methods

OTHER SI UNITSOTHER SI UNITSmolmolkgkg

Measurements Sample PreparationFieldField MeasurementsMeasurements

Complex Matrix Certified Reference Materials

Complex Matrix Certified Reference Materials

Sampling

Validation% of Recovery

Practical Realization of Traceability in Chemical Measurements

Unc

erta

inty

Unc

erta

inty

Potential Primary Methods in CENAMPotential Primary Methods in CENAM

Method Mathematical EquationGravimetry(Inorganic, Static GravimetricPrimary System)

Coulometry

Isotopic Dilution with MS

zFQn =

sB

Bsp

Bsp

pB

sp

sp

p

p

RRRR

RRRR

NN

Mm

n−−

⋅−−

⋅⋅=`

´

`

Mmn =

GravimetryGravimetry

Inorganic Division2001

Traceability in GravimetryTraceability in Gravimetry

Amount of substancemol

Amount of substancemol

Quantity : MassUnit : kgUncertainty : 0.0023 mgPrototype Standard No. 21

Quantity : MassUnit : kgUncertainty : 0.0023 mgPrototype Standard No. 21

Quantity: amount of substance content of Naand Si

k = (40 and 400) mmol/kg

Relative Uncertainty: (0,6)%

Quantity: amount of substance content of Naand Si

k = (40 and 400) mmol/kg

Relative Uncertainty: (0,6)%

Ar(12C)Rel. atomic mass

12Cg mol-1

Ar(12C)Rel. atomic mass

12Cg mol-1

Quantity: MassUnit : kgUncertainty: 0,02 a 0,14 mg

Quantity: MassUnit : kgUncertainty: 0,02 a 0,14 mg

Ar = Rel. atomic mass (Na, Si)Unit: (22,989770 and 28,08559) gmol-1Uncertainty: (0,000002 and 0,0003) gmol-1

Ar = Rel. atomic mass (Na, Si)Unit: (22,989770 and 28,08559) gmol-1Uncertainty: (0,000002 and 0,0003) gmol-1

Mathematical equation of Gravimetry

Quantity: amount of substancecontent of Na and Si

Unit: mmol/kg

Mathematical equation of Gravimetry

Quantity: amount of substancecontent of Na and Si

Unit: mmol/kg

),(),( xSnxEn ba =

xmaxSnbxEk ),(),( =

GravimetryGravimetry

Gas MetrologyOrganic Division

2002

Static Gravimetric System

TraTraceceabilityability in Gas in Gas MetrologyMetrology

kg (SI)(0 µg)

Atomic mass/mol(IUPAC)

PureGases

Purity Determination

National PatternPrototype No.21 (± 2 µg)

Gas Primary Mixtures

ISO 6143

Certified Gas Reference Mixtures

Transference Method

0,1 %

0,3 - 1 %

1 5 %

mol

FundamentalRatio

Frame of massesClass E2

ISO 6142

0

2

1

3

LEVEL

Gas Working Mixtures

CoulometryCoulometry

Inorganic Division1999

CoulometricCoulometric TitrationTitration

VoltV

NS of electrical tension(continuous current)

seconds

NS of time

ohmΩ

NS of electric resistance(continuous current)

kilogramkg

NS mass

VoltageV

NanovóltmetroHP 34420A

times

Contador universalHP 53131A

resistanceΩ

Resistencia PatrónGuildline 9334/100

masskg

Balanza analíticaMettler AT260

intensity(I)A

Ampers

PRIMARY CRM

time(t)s

second

FaradayConstant (F)

CODATA(1998)

Potentiometer(pH)

Potentiostat (I)

mass(m)g

gram

zFtIn =Analite

End Point

IDMSIDMS

Inorganic Division2001

pHpH PrimaryPrimary SystemSystem

Organic Division1999

ConductivityConductivity PrimaryPrimary SystemSystem

Organic Division2002

Measuring systems developed in CENAMMeasuring systems developed in CENAM

SystemSystem Mathematical EquationMathematical Equation

pH Primary System

Conductivity PrimarySystem

pH Secondary System

Conductivity SecondarySystem

+

−= θθ

θ γγp

pF

RTmmm

FRTEE HClClHH

AgClAg2log

210ln

)(log10ln

2/

)( 12 RRg−

=κ2

4φπ ⋅∆⋅

=∆

=L

aLg

RKcelda=κ

Certification of CRMCertification of CRM

♦ 600-AC PL.20 Particular methods of certification in the area ofmaterials metrology

Primary MethodAt least two Independent Reference MethodsValue assignment by method-dependent measurementCollaboration studies with NMIsA combination of the above

Based on the ISO Guide 35:1989, Certification of reference materials –General and statistical principles. 1989

Reference Measurements Systems at CENAMReference Measurements Systems at CENAMCeramics DivisionX Ray fluorescence spectrometryParticle size and distributionPorosity and superface area measurement systemX Ray diffractionFourier transform Infrared spectrometryMicroprobe SystemScanning electro microscope with EDS and WDSSieving and Milling Laboratory

Inorganic DivisionGravimetric-potentiometric titrationUV-Vis spectrophotometryFlame atomic absorption spectrometry (FAAS)Hydride generation and Cold Vapor atomic absorption spectrometry (HG/CV-AAS)Graphite furnace atomic absorption spectrometry (GFAAS)Inductively coupled plasma optical emission spectrometry (ICP_OES)Inductively coupled plasma with high resolution mass spectrometry (ICP-HRMS)Measurements Systems of Nitrogen/Oxygen and Carbon/SulfurGravimetric Preparation Laboratory

Organic DivisionHigh performance liquid chromatography coupled to Diode Array Detector (HPLC)High performance liquid chromatography coupled to UV-Vis detectorHigh performance liquid chromatography coupled to refractive IndexHigh performance liquid chromatography coupled to electrochemical detectorHigh performance liquid chromatography coupled to florescence detector Gas chromatography coupled to quadrupole mass spectrometry (GC-MS)Gas chromatography coupled to high resolution mass spectrometryGas chromatography coupled to electron capture detectorGas chromatography coupled to photoionization detectorGas chromatography coupled to thermo conductivity detectorDifferential scanning calorimetryGravimetric Preparation Laboratory

Human ResourcesHuman Resources

48TOTAL

2Directorate

6Coordination of Reference Materials Program andQuality Control Assurance

2Instrumental

3Other Materials14

3Sediments, Soils, Ores, and Particulates13

1Fuels12

3Food11

3Biological Fluids and Materials10

1Advanced Materials9

1Metals and Metal Alloys8

1Electrolytic Conductivity7

1pH6

4Water5

6Gases4

4Organic Solutions3

4Inorganic Solutions2

3High Purity Chemicals1

StaffCategoryCat. No.

CRM Development StagesCRM Development Stages

Justification

Feasibility evaluation

Preparation or adquisition

of raw material

Homogeneity Tests

Chemical measurements

Statistical Analysis

Certification

Stability Tests

Experiment design

Yes

No

Yes

No

Communication with thecustomer

No

Experiment design

Corn Leaves RMCorn Leaves RM

CleaningNon ionic detergent

Drying60°C

Milling/sieving75 um

Homogenization

Microbiological ControlCobolt-60, 27.8 kGy

Recollection and selection of leavesMiddle life

Preparation of RM

Random and stratified samplingRandom and stratified sampling

ExampleExampleExperiment Design for CertificationExperiment Design for Certification

Objective: To assess the reproducibility between samples and Instrument response (days)

n bottles

Solutions

Day 2Calibration

Day 3Calibration

Day 1Calibration

Replicates Replicates Replicates

To measure nsamples randomOrder

To measure nsamples randomOrder

To measure nsamples randomOrder

Preparation of RMPreparation of RMReference Inorganic SolutionsReference Inorganic Solutions

Purity MeasurementHigh Purity Metals and Salts

ICP-HRMS Systems of measurement in Nitrogen/Oxygen and Carbon/Sulfur

Cleaning and Ampouling Process Gravimetric Preparation

Gravimetric Preparation

Certification process

Chemical MeasurementsChemical MeasurementsSpectrometric Standard Solution,1000 mg/LSpectrometric Standard Solution,1000 mg/L

Value AssignmentValue Assignment

983985987989991993995997999

10011003100510071009

GravimetricPreparation

ICP-OES FAAS Combination Assignment Valuewith TL

Con

cent

ratio

n, m

g/L

K , DMR-57b

11) mg/L±(996

996.3C =

Correction of measured value by transpiration loss for 2 years

11.1U =995.3C =

11.1 (u*K + %T1 year) =U =

0.995 0.9953 1 year the stability in concentration %T1 year =

1.99 0.2 % for 2 years =if %T2 years =

Transpiration loss (TL)

CRM

Policy relative to Uncertainty estimationPolicy relative to Uncertainty estimation

100-ACP100-ACP 2.3.10 Policy for uncertainty estimation2.3.10 Policy for uncertainty estimation

♦ To establish guidelines to report the uncertainty of measurement which isassociated to the CENAM measurements

♦ Applicable to all measurements results of the CENAM procedures

♦ Definitions ui, uc and U

♦ Percent of measurement results Y that can be contained in a reliable wayinside a confidence interval

♦ Every document in which CENAM declare a measurement value, must beaccompanied with a quantitative declaration of its uncertainty

ThreeThree policies and policies and OneOne procedure related to uncertainty procedure related to uncertaintyestimation in Metrology of Materials Areaestimation in Metrology of Materials Area

♦ Declaration of uncertainty for reference materials certification 600-AC.PL.08To Assess that the uncertainty estimation corresponding to chemical measurement carried out inthe Metrology Materials Area must include evaluation of uncertainty.Adopt the guide “Quantifying Uncertainty in Analytical Measurement, English edition, Firstedition 1995 “(1), as a mandatory reference document to assess the chemical measurements.

♦ Combination of Measurement results and uncertainties in reference materialcertification 600-AC.PL.14

Established to assess the consistence of the results issued through the reference materialscertificate with the combination of uncertainty procedure 600-AC.P-014, when it is necessary.It is adopted the document: “An Approach to Combining Results From Multiple MethodsMotivated by the ISO GUM” (1), as a mandatory guide reference when more than one method isaplyed

♦ Acceptance criteria of the certified value and its uncertainty 600-AC. PL.21Measurement methods of quantification must be on statistical control.

♦ General procedure 600-AC.P-113Guide to The expression of uncertainty in measurement, BIPM, IEC, IFCC, ISO, IUPAC, IUPAP,OIML, 1995

(1) JOURNAL OF RESEARCH OF THE NIST, V 105, No. 4, Jul-Ago 2000. U.S.A.

CRM Program Established at CENAMCRM Program Established at CENAMInformation collected by National Standards (NOM, NMX)Information collected by National Standards (NOM, NMX)

Number of testing laboratories accredited = 300

Number of tests = 967 Compulsory standards = 178Non compulsory standards = 789

Total = 968

Compulsory Standards

Total reviewed

Voluntary Standards Total reviewed

Environmental 94 Chemical 203 Food 28 Agricultural 138 Chemical 16 Food 141 Beverages 9 Plastic 67 Services 6 Environmental 53 Plastic 5 Petrochemical 51 Other manufactures 5 No ferrous metals 40 Iron and steel industry 4 Control and

measurement equipment 13

Petrochemical 2 Glass industry 11

Developed CRM by Metrology of MaterialsDeveloped CRM by Metrology of MaterialsNo. CRM

53

1621

9

16

32 33

25

8

05

10

15202530

3540

1994 1995 1996 1997 1998 1999 2000 2001 2002 2003Year

No. o

f CRM

29%

25%

8%

8%

7%6%5%4%3%

1%

1%

1%

2%Ino rganic So lut ions Organic So lut ions High Purity CompoundsSed iments , So ils and Part icules Food OtherspH Water FuelsAdvanced Materials Conduct ivity Metals and Metals AlloysBio log ical Fluids and Materials

69 gas mixtures, CRM forinternal use in order to support:PTsMRTC programCalibration servicesEvaluation of analyticalcompetence

168 CRM

CRM Available at CENAMCRM Available at CENAM

ServicesServices offered by Metrology of Materials Areaoffered by Metrology of Materials Area

15Technical assistance in metrology inchemistry

23Training in the laboratories

511Training courses in catalogue & by request

6742Special analytical services

2845Gas analyzer calibration

13221462CRM Sales

No. services2003

Jun-Sep

No. services2002

Type of service

Reference Material sold by applicationReference Material sold by application

3 7%

2 4 %

14 %

14 %

6 %2 %2 %1%

S pe c t rome t r ic solut ions Ele c t roc he mic a l st a nda rs Food indust ry a pplic a t ion

Wa st e wa t e r a na lysis Che mic a l a nd pe t roc he mic a l a pplic a t ion Ge ne ra l a pplic a t ion

Envirome nt a l a na lysis Ce ra mic , c e me nt a nd gla ss

19 32 51181

297

630

1462 1322

0

200

400

600

800

1000

1200

1400

1600

1996 1997 1998 1999 2000 2001 2002 2003Year

No.

of C

RM

Sol

d

CRM CRM SoldSold

4 1998

H+ He 6 1999

Li Be B C N O F- Ne 9 2000

Na Mg Al Si P S Cl- Ar 3 2001

K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr 3 2002

Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe 1 2003

Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn 5 2004

Fr Ra Ac Ku Ha 5 2005

Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu 5 2006

Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lw 6 2007

In program: 47Total : 26 (2003)

CRM

Calibration Solutions and High Purity SaltsCalibration Solutions and High Purity SaltsNational Needs and DevelopmentNational Needs and Development

speciation High Purity SaltsReferenceSolutions

Cu Hg Cr+6 NaCl HClNi Se Cl - KCl H2SO4

Pb Sn F- K2Cr2O4

Zn P PO4- BFK

Al Sb NO3- Na2CO3

Ca As SO4= CaCO3

Cd Mn NO2- As2O3

Fe Ti Oxalato de NaK Bi Tris(hidroximetilaminometano)

Mg Li Acido OxálicoNa Mo EDTASi PtS TlAg VCr W

BBaGaInYCsCo

15 17 + 5 7 11 215 22 7 11 2

Salts Solutions11 41 + 511 46

National Needs: 53

Elemental

CoulombimetryReference Solutions

55 CRM

Organic CRMOrganic CRMNational NeedsNational Needs

•• Environmental (Gas, soil, water, sediments)Environmental (Gas, soil, water, sediments)•• Health and ClinicalHealth and Clinical•• High Purity organic compoundsHigh Purity organic compounds•• Biological MaterialsBiological Materials•• Food and beverageFood and beverage•• Petroleum ProductsPetroleum Products

DevelopmentDevelopment79 Certified reference materials for:

•• Nutritional constituents in food samples (vitamins like, A, C, E,Nutritional constituents in food samples (vitamins like, A, C, E, fatty acids, minerals) fatty acids, minerals)

•• PesticidesPesticides•• ketonesketones, , aldehydesaldehydes, alcohols mixtures for alcoholic industry, alcohols mixtures for alcoholic industry•• HydrocarbonsHydrocarbons•• Gas mixtures Gas mixtures (69)•• pHpH•• Electrolytic conductivityElectrolytic conductivity

Electrical Metrology

Physical Metrology

Materials Metrology

Mechanical Metrology

CENAMCENAM Services in Appendix C, BIPM KCDBServices in Appendix C, BIPM KCDB

Published in BIPM Annex C

ElectromagneticMeasurements

36

Temperature

20

Time and Frequency

---

Acoustics and Vibrations

16

Optics and Radiometry

13

CeramicMaterials

--- 8*

Length

13

Flow and volume

5

Force andpressure

22

Mass

45

TOTALMat. Met 31 + 43 = 74

213

* RM covered by Cycle III and IV

MetallicMaterials

38 + 8*Organic Materials

5 + 15*

There is NO one to one correspondence between BIPM servicesand our service catalogue

2

4

106

10

10

CCQM

SIM

Traceability can be established through national standardsand through those of other countries.

Due to the lack of CRMs most analytical laboratories employ chemicals with certificate of analysis which does not containsufficient information for demonstrating their traceability to national standards

At the same time there are few national standards which could give traceability to them.

Reference LaboratoriesReference Laboratories

CENAM´s annual sale of CRMS is now ca. 1500 units

Evaluation of traceability of Certificates of RMis over 5000.

Absolute lack of capabilityLack of strategy of priority CRMsLack of mechanism to produce CRMs

MRTC program to work together with RM producersAnd Reference Laboratories

Reference LaboratoriesReference LaboratoriesCENAM ProposalCENAM Proposal

Reference LaboratoriesReference LaboratoriesCENAM ProposalCENAM Proposal

CENAMCENAM NMINMI

HEALTH R L ENVIROMENTAL R L AGRICULTURE R L AGRICULTURE R L

LAB.LAB. 1 LAB. 3LAB. 3 LAB. 5LAB. 5 LAB. 6LAB. 6 LAB. nLAB. n

Analytical Laboratories, Private Research Institutes, Universities, GovernmentResearch Institutes, etc.

LAB.LAB. 2 LAB.LAB. 4 LAB.LAB. 7

MetrologicalMetrological ActivitiesActivities ofof ReferenceReference LaboratoriesLaboratories

♦ Maintain traceability to SI

♦ Disseminate accuracy to the National Standards toward thetesting laboratories by means of:

Preparation Capabilities of candidates RMMeasurement Capabilities

♦ Guarantee: harmonize and reliable chemical measurements,which will be carried out in the country.

CRMCRM networknetwork andand PT PT providersproviders: : proposedproposed schemeschemewithwith ReferenceReference LaboratoriesLaboratories (a-e) (a-e)

NORAMET

NRC NIST

CENAM

5.2 Water, Contaminated Water

3. Organic Sol.

SIMSIM

4.2 Gas, environmental 10.4 Botanic M.,Tissues

11.1, 11.2 Food, Nutritional and Contaminants

ab c d

e

CENAM &Reference Labs

NORAMET/SIM CRM network

PTsPTs (Waste Water Laboratories) (Waste Water Laboratories)

Hg

0

50

100

150

200

250

300

1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004Year

% R

SD

As

0

5

10

15

20

25

1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004

Year

% R

SD

Cd

0

5

10

15

20

25

1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004Year

% R

SD

PTsPTs (Waste Water Laboratories) (Waste Water Laboratories)

Cr VI

0

5

10

15

20

25

1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004

Year

% R

SD

CN

05

10152025

303540

4550

1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004

Year

% RS

D

Fig. 1a Mean values and standard deviation for Glucose concentration in sample 1

Certified value ± U ± 3U

CERTIFIED VALUE: 88.7 mg/dLUncertainty (U): ± 1.68 mg/dL

70.0

80.0

90.0

100.0

110.0

7390

2315

4817

5429

2710

3811

7375

9359

5437

6344

2556

7663

1740

9900

8063

7636

7266

1524

5528

6527

8127

2161

7242

2890

4617

4953

6865

4891

3337

6840

6986

6234

8224

3554

2667

9983

7786

8004

1952

2991

2884

4483

3207

3683

LABORATORY CODE

CO

NC

ENTR

ATI

ON

(m

g/dL

)

*Colorimetric (QH) Dried Chemestry (QS) O2 Electrod (O2Z)Not reported (NR)METHOD:

Impact on health and trade

EU Directive on IVD: CEN/TC 140ISO/TC 212 for IVD test systems

PTsPTs (Clinical Laboratories) (Clinical Laboratories)

InternationalInternational CollaborationCollaboration in in ChemicalChemical MetrologyMetrology ProgramProgram

Within SIM since 1995 CENAM collaboration with:Jamaica, Chile, Costa Rica,Ecuador, Argentina

Bilateral since training and development in:NIST 1992PTB 1996BAM 2001KRISS 2002NMIJ 2003

All fields Primary methods, uncertaintyGas metrology, IDMS, Soils CRMIDMS (organics)Planning

CONCLUSIONSCONCLUSIONS

Traceable measurements are fundamental for reliability of regulatory actions.

Traceability could be achieved by establishing reference points of the chain of comparison:

Reference MethodsReference Materials/devicesReference measuring instruments

Practical ways in establishing traceability is to conform anorganization of responsible member entities with specifictasks in metrology, corresponding to reference point

Centro Nacional de Metrologíae-mail: servtec@cenam.mx materiales@cenam.mx

mesura@cenam.mxWeb site: http://www.cenam.mx

November, 2003

More information to:

CENAM provides services to meet the needs of the society

to establish traceability of Measurementsin Mexico for competitiveness and reliability

Economic growth with qualityThank you for your attentionThank you for your attention