B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 1.

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B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 1

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 2

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 3 THE GENERAL AIM OF ANALYTICAL CHEMISTRY IS TO MAKE THE INTRINSIC BUT LATENT INFORMATION ON AN OBJECT EVIDENT, MEASURABLE, TRUTHFUL AND USEFUL INFORMATION CHEMICAL EVIDENT MEASURABLE AVAILABLE LATENT INTRINSIC USEFUL TRUTHFUL IDENTIFICATIONORIGIN CHARACTERIZATION QUALITY APPLIEDBASIC TECHNICAL

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 4 THE MAIN GOAL OF ANALYTICAL CHEMISTRY IS TO MINIMIZE UNCERTAINTY ON THE CHEMICAL INFORMATION OF A OBJECT OR A SYSTEM THREE TYPES OF CHEMICAL INFORMATION ANALYTICAL INFORMATION ROUTINELY PRODUCED REAL QUALITY INFORMATION CONSIDERED TO BE TRUE A C C U R A C Y U N C E R T A I N T Y REFERENTIAL QUALITY INTRINSIC INFORMATION IDEAL QUALITY TRUENESS

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 5

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 6

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 7

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 8 IS METROLOGY IN CHEMISTRY UNDER THE RESPONSIBILITY OF ANALYTICAL CHEMISTRY? THE EXCLUSIVE GOAL OF ANALYTICAL CHEMISTRY? RELATED TO THE FOUNDAMENTALS OF ANALYTICAL CHEMISTRY? RELATED TO THE QUALITY OF THE ANALYTICAL INFORMATION? DIRECTLY YES NO INDIRECTLY RELATED TO FITNESS FOR PURPOSE?

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 9

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 10

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 11

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 12

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 13 B A S I C SPECIFIC T R E N D S DISTINCTION INTRINSIC AND SHARED FOUNDAMENTALS

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 14

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 15

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 16

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 17

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 18 DIFFERENCES BETWEEN CHEMICAL (CMPs) AND PHYSICAL MEASUREMENT PROCESSES (PMPs) CMPs ARE STRONGLY SAMPLE-DEPENDENT PMPs ARE VIRTUALLY SAMPLE-INDEPENDENT QUITE SIMILAR PMPs CAN BE APPLIED TO MEASURE THE LENGTH OF A TABLE I THE HEIGHT OF A TREETHE DISTANCE BET- WEEN TWO OBJECTS DIFFERENT CMPs (MAINLY THE FIRST STEP) MUST BE APPLIED FOR THE DETERMINATION OF A PESTICIDE IN WATERS (from spring to waste waters) SOILS SEDIMENTS PLANTS BIOLOGICAL FLUIDS COMMERCIALLY AVAILABLE FORMULATIONS SOILS

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 19 DIFFERENCES BETWEEN CHEMICAL (CMPs) AND PHYSICAL MEASUREMENT PROCESSES (PMPs) II AS A CONSEQUENCE OF MILLIONS OF CHEMICAL SPECIES THOUSANDS OF SAMPLE TYPES PRACTICAL LIMITATION OF METROLOGY IN CHEMISTRY FEW GENERAL CMPs ARE AVAILABLE COMBINATION CMPs ARE HIGHLY VARIED; BY CONTRAST, THERE ARE LESS PMPs WHICH ARE MORE GENERAL

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 20 DIFFERENCES BETWEEN CHEMICAL (CMPs) AND PHYSICAL MEASUREMENT PROCESSES (PMPs) III POPO PRELIMINARY OPERATIONS OF MEASURING PROCESSES IN CMPs PMPs GREAT IMPACT CMPs GREAT SIGNIFICANCE LITTLE IMPORTANCE FROM A PRACTICAL POINT OF VIEW ON THE QUALITY OF RESULTS SAMPLE RANDOM SYSTEMATIC ERRORS - TEDIOUS - TIME-CONSUMING - SOURCE OF - HAZARDS FOR ANALYST AND ENVIRONMENT RESULTS PMPs MEASURING AND TRANSDUCING THE SIGNAL DATA HANDLING AND TREATMENT PRELIMINARY OPERATIONS RESULTS MEASURING AND TRANSDUCING THE SIGNAL DATA HANDLING AND TREATMENT

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 21 DIFFERENCES BETWEEN CHEMICAL (CMPs) AND PHYSICAL MEASUREMENT PROCESSES (PMPs) IV PMPs RELY ALMOST EXCLUSIVELY ON DIRECT-USE INSTRUMENTS MEASUREMENT EQUIPMENT ARE NOT THE SOLE FOCUS IN CMPs: MANY OTHER FACTORS AFFECT THE QUALITY OF RESULTS

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 22 DIFFERENCES BETWEEN CHEMICAL (CMPs) AND PHYSICAL MEASUREMENT PROCESSES (PMPs) V SAMPLING HETEROGENEITY OF OBJECTS AND SAMPLES INTRODUCES SERIOUS ERRORS IN CMPs THIS PROBLEM IS ALMOST EXCLUSIVE OF METROLOGY IN CHEMISTRY KEY ASPECT IN CMPs TO ASSURE REPRESENTATIVENESS DOES NOT EXIST OR IS QUITE SIMPLE IN PMPs

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 23

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 24

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 25

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 26

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 27 EXAMPLE TITRIMETRIC DETERMINATION OF CL 2 (OXIDANT) Kg / MOLE ATOMIC WEIGHTS (I, O, K, S, Cl KIO 3 SI UNITS CHEMICAL STANDARDS ANALYTICAL STANDARDS STOICHIOMETRY S 2 O 3 2- ANALYTICAL STANDARDS TITRIMETRY PRIMARY 1st stepIO I - + 6H +  3I 2 + 3H 2 O 2nd stepI 2 + 2S 2 O  S 4 O SECONDARY ANALYTE 1st stepCl 2 + 2I -  2Cl - + I 2 2nd stepI 2 + S 2 O  S 4 O I - BURETTE IO I 2 - 6S 2 O I 2 - 6Cl 2

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 28

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 29

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 30

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 31

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 32

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 33 PRACTICAL APPROACHES TO METROLOGY IN CHEMISTRY II SAMPLING PRELIMINARY OPERATION OF CMPs THAT CAN SIGNIFICANTLY CONTRIBUTE TO THE UNCERTAINTIES OF RESULTS NEED TO SYSTEMATICALLY CONSIDER SAMPLING IN QUALITY SCHEMES, NORMS, GUIDES CONCERNING METROLOGY IN CHEMISTRY

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 34 PRACTICAL APPROACHES TO METROLOGY IN CHEMISTRY III UNCERTAINTY CALCULATIONS UNCERTAINTY IS A KEY ASPECT OF TRACEABILITY: IT IS NECESSARY TO IDENTIFY ALL SOURCES OF UNCERTAINTY MAIN APPROACHES TO QUANTIFYING UNCERTAINTY IN CHEMICAL ANALYSIS BOTTOM-UP APPROACH - Guide to the Expression of Uncertainty in Measurements (1995) ISO - Quantifying Uncertainty in Analytical Measurement (1995) EURACHEM see next transparency FAR FROM THE REALITY IN CHEMICAL MEASUREMENTS GLOBAL APPROACH OTHERS

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 35

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 36

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 37 DEFINITION AIM MEASUREMENT STANDARDS ANALYTICAL CALIBRATION CHARACTERIZING THE INSTRUMENTAL RESPONSE IN TERMS OF ANALYTE PROPERTIES TO ESTABLISH AN UNEQUIVOCAL RELATIONSHIP BETWEEN SIGNALS AND ANALYTE CHARACTERISTICS FOR BOTH QUALITATIVE AND QUANTITATIVE PURPOSES CONTAIN THE ANALYTE EXCEPT IN FACTORING (TITRIMETRY) EQUIPMENT CALIBRATION CHECKING THE CORRECT OPERATIONS OF AN INSTRUMENT OR APPARATUS EQUIPMENT TO CORRECT THE INSTRUMENT RESPONSE OF THE PARAMETRIC REACTING OF AN APPARATUS DO NOT CONTAIN THE ANALYTE P M P s C M P s

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 38

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 39

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 40

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 41 PRACTICAL APPROACHES TO METROLOGY IN CHEMISTRY V V A L I D A T I O N THE TWO FACETS OF ANALYTICAL QUALITY ARE INVOLVED TO ASSURE ALTHOUGH METHOD VALIDATION IS THE MOST PROMINENT ACTION IN THIS CONTEXT; THERE ARE OTHER APPLICATIONS SUCH AS "DATA VALIDATION", "SOFTWARE VALIDATION", etc. THERE IS A NEED TO ESTABLISH A HIERARCHY IN THIS CONTEXT. METROLOGICAL QUALITY FITNESS FOR PURPOSE

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 42

B. Neidhart, W. Wegscheider (Eds.): Quality in Chemical Measurements © Springer-Verlag Berlin Heidelberg 2000 M. ValcárcelMetrology in Chemistry 43