B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 A. RíosTraceability / Trackability 1 It is being increasingly used in the analytical chemistry domain because of the growing of the analytical Quality Systems. Traceability is a generic, basic concept, inherent in Analytical Chemistry (the science of chemical measurements). T The definitions from dictionaries (1,2) deal with 1. Traceability (noun) : ‘the quality of being traceable’. 2. Traceable(adjective) : ‘capable of being traced’; ‘suitable or of a kind to be attributed’. 3.To trace (verb) : ‘to follow or study out in detail or step by step’; ‘to follow the course, development or history of’; ‘to outline or present the development, progress or history of’. (1) Oxford English Dictionary, Oxford University Press, Oxford, 2 nd Edition, 1989 (2) Webster’s Third New International Dictionary, Merrian- Webster, Chicago, 1981.

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 A. RíosTraceability / Trackability 2 RESULTS SYSTEM UNDER STUDY Measurement(s) Physical measurements CALIBRATED EQUIPMENT SampleResults Chemical measurements SampleResults VALIDATED ANALYTICAL PROCESS

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 A. RíosTraceability / Trackability 3 TRACEABILITY / TRACKABILITY T Definitions and meanings.

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 A. RíosTraceability / Trackability 4 (ISO Guía 25) Analytical result CONCENTRATION TRACEABILITY analyte weight sample weight REFERENCE KILOGRAM Definitions TRACEABILITY (ISO, 1984) The property of a result of a measurement whereby it can be related to appropriate standards, generally international or national standards, through an unbroken chain of comparisons. TRACEABILITY (ISO, 1993) Property of the result of a measurement or the value of a standard whereby it can be related to stated references, usually national or international standards, through an unbroken chain of comparisons all having stated uncertainties. M ±N CHEMICAL REFERENCE

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 A. RíosTraceability / Trackability 5 KG MOL AMPERE SECOND WEIGHT OF C-12 N AVOGADRO FARADAY ATOMIC WEIGHTS ULTRAPURE SILVER PRIMARY STANDARDS WORKING STANDARDS S.I. BASIC STANDARDS CHEMICAL STANDARDS ANALYTICAL STANDARDS Operational standards

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 A. RíosTraceability / Trackability 6 B B B B B A A A A A A RESULTS LAB. 1 RESULTS LAB. 2 RESULTS LAB. 3 STANDARDS BASE (S.I. units) STANDARDS

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 A. RíosTraceability / Trackability 7 Analytical / Metrological properties M±N TRUENESS TRACEABILITY PRECISION UNCERTAINTY

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 A. RíosTraceability / Trackability 8 SAMPLE RESULTS ANALYTICAL PROCESS In a general analytical process, traceability is assured through: TRACEABILITY OF MEASUREMENT STANDARDS. CALIBRATION (apparatus + instruments). VALIDATION OF THE OVERALL ANALYTICAL PROCESS.

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 A. RíosTraceability / Trackability 9 Demonstrating traceability of analytical results SAMPLE CRM (matrix type) ANALYTICAL PROCESS RESULTS Comparison against the certified value t test : t exp < t crit (P, n-1, 2 tails)

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 A. RíosTraceability / Trackability 10 Primary methods Certified reference materials Reference methods Collaborative studies Working reference materials Reference instruments Material formulation Spiked samples Alternative techniques References and their hierarchy

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 A. RíosTraceability / Trackability 11 g Fe = (Product weight) 2 Fe Fe O 23 standard kilogram certified weights (CALIBRATION) SAMPLE Fe 3+ Fe(OH) 3 Fe O 23 dissolution OH Example : G R A V I M E T R Y WEIGHTS mol, C 12

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 A. RíosTraceability / Trackability 12 Standard-kg weights certified (CALIBRATION) Example : T I T R A T I O N S (sample) TITRANT SOLUTION STANDARD PRIMARY (standardisation?) WEIGHT CALIBRATION TITRATING VOLUME N A V N f BBB V A mol, C 12 V A N A = V B N B f B

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 A. RíosTraceability / Trackability 13 certified weights (CALIBRATION) Standard kilogram SAMPLE PREPARATION CHEMICAL STANDARD CALIBRATED INSTRUMENT SAMPLE MEASUREMENT Conc. Signal ANALYTICAL CALIBRATION y = a + bx  “CALIBRATION OF EQUIPMENTS” (to be sure that the equipment works appropriately in a general way) “ANALYTICAL CALIBRATION” (to define the specific relationship between the instrumental signal and the concentration of a particular species) Example : INSTRUMENTAL ANALYSIS

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 A. RíosTraceability / Trackability 14 ISO Quality Management and Quality Assurance Vocabulary (1994). TRACEABILITY Ability to trace the history, application or location of an entity by means of recorded identifications. TRACING CONNOTATION 1. THE TERM TRACEABILITY MAY HAVE ONE OF THREE MAIN MEANINGS: (a) In a productive sense, it may be related to: 1. The origin of materials and parts. 2. The product processing history. 3. The distribution and location of the product after delivering. (b) In a calibration sense, it relates measuring equipment to national or international standards, primary standards, basic physical constants or properties, or reference materials. (c) In a data collection sense, it relates calculations and data generated throughout the quality loop, sometimes back to requirements for quality for an entity. 2.. ALL ASPECTS OF TRACEABILITY REQUIREMENTS, IF ANY, SHOULD BE CLEARLY SPECIFIED (for instance, in terms of period or time, point of origin or identification).

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 A. RíosTraceability / Trackability 15 ACCURACY 'TARGET' T R A C E A B I L I T Y

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 A. RíosTraceability / Trackability 16 “ Property of a result of a measurement or the value of a standard whereby it can be related to stated references, usually national or international, through an unbroken chain of comparisons all having stated uncertainties “ “ The ability to trace the history, application or location of an entity by means of recorded identifications “  ISO ( Quality Management and Quality Assurance Vocabulary ) ISO ( International Vocabulary of Basic and General Terms in Metrology )

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 A. RíosTraceability / Trackability 17 RELATIONSHIP TO REFERENCES HISTORY OF THE GENERATION OF A PRODUCT OR THE BEHAVIOUR OF A SYSTEM TRACEABILITY Integral approach

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 A. RíosTraceability / Trackability 18 Ability to relate entities with well-established landmarks or references Ability to relate entities with well-established landmarks or references The integral approach of traceability “STANDARDS” The integral approach of traceability “STANDARDS” Written standards (INTANGIBLE) Measurement standards (TANGIBLE) STANDARDS NORMS ENVIRONMENTAL STANDARDS (criteria, limits, etc.) NORMS ENVIRONMENTAL STANDARDS (criteria, limits, etc.) OBJECTS (v.i. a CRM) OBJECTS (v.i. a CRM) PROCEDURES

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 A. RíosTraceability / Trackability 19 “ TRACKABILITY “ J. Fleming, B. Neidhart, Ch. Tausch and W. Wegscheider. Accreditation & Quality Assurance, 1 (1996) 43. The property of a result of a measurement whereby the result can be uniquely related to the sample (The result of a measurement can be linked unambiguously to the sample to which it refers) CALCULATION DETERMINATION RESULT SEPARATION PREPARATION STORAGE SAMPLING

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 A. RíosTraceability / Trackability 20 J. Fleming, H. Albus, B. Neidhart and W. Wegscheider Accred. Qual. Assur. (1996) 1, 234. “Trackability is not a property of the results of measurement but more a property of the system” The definition should be: “The property of a system which enables the ready retrieval of the different elements of a record to allow unambiguous correlation with an uniquely identified sample”

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 A. RíosTraceability / Trackability 21 TRACEABILITY / TRACKABILITY T Do we need the ‘trackability’ term ?

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 A. RíosTraceability / Trackability 22 Traceability in Analytical Chemistry Miguel Valcárcel and Angel Ríos The Analyst, 120 (1995) ECONOMIC OR SOCIAL PROBLEM ANALYTICAL PROBLEM OBJECT BULK SAMPLE SAMPLES ALIQUOTS ANALYTICAL PROCESS RESULTS REPRESENTATIVENESS SAMPLE CUSTODY CHAIN

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 A. RíosTraceability / Trackability 23 Why not a wider definition of traceability ? Property of a result of a measurement, linked unambiguously to the sample to which it refers, or the value of a standard whereby it can be related to stated references, usually national or international, through an unbroken chain of comparisons all having stated uncertainties; and the ability to trace the history, application or location of all the elements involved in the generation of such result by means of recorded identifications.

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 A. RíosTraceability / Trackability 24 TRACEABILITY of... A RESULT A STANDARD AN EQUIPMENT A SAMPLE A METHOD Related to its SAMPLE Related to STANDARDS ( Representativeness ) ( Traceable methods ) IS TRACEABILITY AN EXCLUSIVE PROPERTY OF ANALYTICAL RESULTS ? An extended approach to traceability in chemical analysis. M. Valcárcel and A. Ríos Fresenius J. Anal. Chem. (1997) 359:

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 A. RíosTraceability / Trackability 25 TRACEABILITY OF A RESULT HISTORY OF ITS GENERATION Elements defining and documenting the “history” of a result. HUMAN MATERIAL INSTRUMENTAL METHODOLOGICAL ENVIRONMENTAL TEMPORAL WHO ? WHAT ? HOW ? WHEN ?

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 A. RíosTraceability / Trackability 26 TRACEABILITY OF A CRM (1) PREPARATION - Origin of the material (natural or artificial). - Analytes spiked or originally contained. - Studies performed on both homogeneity and stability. - Etc. (2) CERTIFIED VALUES - How the values and their uncertainties were established. - Methods used. - Values rejected and reasons. - Standards used by the participating laboratories. - Major sources of error. - Etc. EXAMPLE: Certified reference materials for determination of PCBs in soil samples (*) SFE operational conditions EXPE- RIENCE T ( o C) P (atm) Density Time (g/ml) (min) (1) (2) (3) (#) Recovery ( % ) SRM (NIST) CRM (BCR) Analytes spiked to clean soil Analytes origin- ally contained 99 % 25 % 30 % (#) 100 µL of MeOH previously added to the CRM (*) From P. Sandra

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 A. RíosTraceability / Trackability 27 TRACEABILITY OF AN EQUIPMENT DETAILED, TIMELY AND CUSTOMIZED RECORDING OF: CONSISTENCY WITH ISO’S DEFINITION (ISO ). ISO 9000, EN 45000: ESSENTIAL PART OF QUALITY MANUAL. GLPs: EACH EQUIPMENT MUST HAVE A ‘SOP’. Installation. Breakdowns. Calibrations and corrections. Hours of use. Samples processed. Etc.

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 A. RíosTraceability / Trackability 28 TRACEABILITY OF METHODOLOGIES “Official”, “standards” and “ “reference” methods do not assure the quality of the results. Even methods validated by interlaboratory exercises can produce poor results if incorrectly used. TRACEABLE METHOD 1. In its development. 2. In its routine application. Method that produces results (with their uncertainties) characterised by traceability to established references. “ESTABLISHED REFERENCES”: - Certified reference materials. - Primary methods. Primary measurement method - Highest metrological quality. - Its operations must be thoroughly known and explained. - Its uncertainty must be thoroughly described in terms of basic SI units. - Its results must be accepted without reference to standards of the measured quantity. GRAVIMETRY COULOMETRY ISOTOPIC DILUTION - MS

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 A. RíosTraceability / Trackability 29 TRACEABILITY / TRACKABILITY T Final remarks TRACEABILITY TRACKABILITY ORTHODOX APPROACH (QUASI-) HETERODOX APPROACH OFFICIAL POSITION IN THE QM DOMAINS OFFICIAL METROLOGICAL POSITION Characteristic of an entity. Characteristic of a measuring equipment (in the calibration domain). Property of a result of a measurement. Characteristic of the value of a standard. Metrological characterisation in the chemical measurement domain applicable to aspects such as: - RESULTS - STANDARDS - MEASURING EQUIPMENT - SAMPLE (aliquot) - METHODOLOGIES Emphasis on tracing connotation (QA principles). - New term or new (implicit) facet of traceability concept ? - Is it necessary a new integrated definition of traceability ?

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 A. RíosTraceability / Trackability 30 TRACEABILITY / TRACKABILITY T Some challenges  To make the concepts understandable and accessible so that they are no longer the exclusive patrimony of theoreticians and bureaucrats.  To make the concept of traceability more flexible and practical, in order to facilitate its use.  To expose the fallacy that traceability can only be acceptably referred to the mole and/or kilogram (SI units). Traceability to a well established accessible standard is also quite valid, practical and useful.  To avoid useless arguments (e.g. the MOLE vs. the kg as the ultimate reference in chemical metrology).  To systematically introduce the concepts in Analytical Chemistry education and research.