ISO/TR 16153:2023

TECHNICAL ISO/TR
REPORT 16153
Second edition
2023-02
Determination of uncertainty for
volume measurements of a piston-
operated volumetric apparatus using
a photometric method
Détermination de l’incertitude de mesure pour les mesurages
volumétriques des appareils volumétriques à piston au moyen de la
méthode photométrique
Reference number
© ISO 2023
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ii
Contents Page
Foreword .iv
Introduction .v
1 S c op e . 1
2 Nor m at i ve r ef er enc e s . 1
3 Terms and definitions . 1
4 Modelling the measurement.1
5 G eneral procedure for the uncertainty calculation . 4
6 S tandard uncertainty components associated with the measuring system
(photometric measurement procedure) . 4
6.1 G eneral information on the estimation of standard uncertainty components . 4
6.2 S tandard uncertainty of the copper(II) chloride solution volume . 5
6.3 S tandard uncertainty of the cuvette mixture absorbance at 520 nm . 5
6.4 S tandard uncertainty of the cuvette starting absorbance at 730 nm . 6
6.5 S tandard uncertainty of the cuvette starting absorbance at 520 nm . 6
6.6 S tandard uncertainty of the volume of Ponceau S and copper(II) choloride
solutions used in calibrators . 7
6.7 S tandard uncertainty of the absorbances of the calibrator solutions . 7
7 S tandard uncertainty components associated with the POVA . 9
7.1 S tandard uncertainty of the resolution . 9
7.2 S tandard uncertainty of the setting . 9
7.3 S tandard uncertainty related to air cushion effects . 9
7.4 S tandard uncertainty of the cubic expansion coefficient. 9
8 S tandard uncertainty components associated with the liquid delivery process .10
8.1 R epeatability (experimental standard deviation) . 10
8.2 Reproducibility . 10
9 C ombined standard uncertainty of measurement associated with the systematic
error of mean volume .11
10 Sensitivity coefficients .12
11 Coverage factor k . .13
12 Expanded uncertainty of measurement associated with the volume V .14
13 Example for determining the uncertainty of the volume measurement of POVA .14
13.1 Measurement conditions . 14
13.2 Results . . 16
13.2.1 Standard uncertainty of the POVA mean volume . 16
13.2.2 Expanded uncertainty of the measurement . 17
13.2.3 Result of measurement . 17
13.2.4 Uncertainty in use and corrections for pressure changes . 17
13.2.5 General remarks . 17
13.2.6 Note on the conformity with ISO/IEC Guide 98-3 . 17
Annex A (informative) Approaches for the estimation of uncertainty in use of a single
delivered volume .19
Annex B (informative) Volume correction due to pressure changes .22
Bibliography .24
iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
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ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
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on the ISO list of patent declarations received (see www.iso.org/patents).
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www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 48, Laboratory equipment.
This second edition cancels and replaces the first edition (ISO/TR 16153:2004), which has been
technically revised.
The main changes are as follows:
— the term “standard deviation of the mean delivered volume” has been replaced in this document by
“repeatability” according to ISO/IEC Guide 99 (VIM);
— a new uncertainty calculation example has been supplied;
— new uncertainty components have been added, namely, reproducibility, air cushion and resolution;
— new Annex A concerning the uncertainty in use of a single delivered volume has been added;
— new Annex B concerning volume correction due to pressure changes has been added.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
Introduction
The example given in this document is informative and supports the requirements found in
ISO 8655-8:2022, 9.4 and ISO 8655-7:2022, 4.2, to perform an estimation of measurement uncertainty
when calibrating POVA according to the measurement procedures described in these documents and
the principles of ISO/IEC Guide 98-3.
The revision of this document coincides with a major revision of the ISO 8655 series in 2022, reflecting
the state-of-the-art measurement procedures and approaches for the estimation of measurement
uncertainty.
v
TECHNICAL REPORT ISO/TR 16153:2023(E)
Determination of uncertainty for volume measurements
of a piston-operated volumetric apparatus using a
photometric method
1 S cope
This document gives detailed information regarding the evaluation of uncertainty for the photometric
reference measurement procedure specified in ISO 8655-8 and the photometric procedure specified in
ISO 8655-7:2022, Annex B according to ISO/IEC Guide 98-3.
This document also describes the determination of other uncertainty components related to the liquid
delivery process of a piston-operated volumetric apparatus (POVA), e.g. repeatability and handling.
Furthermore, it provides examples for the calculation and application of the uncertainty of the mean
delivered volume and the uncertainty in use of a single delivered volume.
2 Normat ive references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 8655-1, Piston-operated volumetric apparatus — Part 1: Terminology, general requirements and user
recommendations
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 8655-1 apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 Modelli ng the measurement
The dual-dye ratiometric photometric measurement procedures described in ISO 8655-7 and ISO 8655-8
use a cuvette containing a copper(II) chloride solution of known volume, which is determined by
a gravimetric method. The POVA under test is used to add an unknown volume of test solution with
known Ponceau S concentration to the cuvette containing CuCl solution. The contents of the cuvette
are mixed without removing the cuvette from the light path of the spectrophotometer, and absorbances
at 520 nm and 730 nm are measured before and after the addition of test solution.
Calibrator solutions of CuCl and Ponceau S are prepared, and their absorbance values at 520 nm and
730 nm measured. Preparation of the Ponceau S test solutions of different concentrations involves the
preparation of dilutions, which are expressed by the dilution ratio, R. Absorbances of the calibrator
solutions, together with the dilution ratio, R, are used to calculate the calibration constant, K, for a given
concentration of Ponceau S.
The unknown volume of Ponceau S solution delivered by the POVA under test is calculated from the
volume and absorbances of the CuCl solution prior to addition of test solution, the calibration constant
K, and the absorbance of the mixture in the cuvette after addition of test solution.
The Formula for the total volume V (i) of delivered test solution after the i-th delivery at the test
T
temperature is given by Formul
...