Metrology In Chemistry Research Articles

Development of nuclear magnetic resonance as a tool of quantitative analysis for organic materials

It has been recognized for a long time that nuclear magnetic resonance (NMR) spectroscopy can be used for quantification; the resonance peak area is known to be proportional to the number of nuclei contributing to the peak. However, quantification by Fourier transformation (FT) NMR was believed to be only accurate to within a few percent to 10%, and in general, analytical chemists thought the level of accuracy was not satisfactory. However, about 20 years ago, chemical metrologists began to recognize the usefulness of quantitative applications of NMR for determining the purity of organic materials. Here, we present a brief review on purity assessment of the quantitative NMR (qNMR) and its contribution to the consultative committee for amount of substance: metrology in chemistry and biology (CCQM) working group on organic analysis (OAWG).

Designing a formulation of synthetic wastewater as proficiency testing sample: a feasibility study on a laboratory scale

Monitoring water quality is very crucial for sustainability and availability of clean water on earth. Electrolytic conductivity is one of the important water quality parameters to be monitored according to American Environmental Protection Agency, World Health Organization and Ministry of Environment and Forests Republic of Indonesia. Testing laboratories have a significant role in producing the accurate measurement related to the water quality parameters including electrolytic conductivity. Therefore, participating in a proficiency testing (PT) is mandatory, especially for the accredited testing laboratories, to demonstrate the competency of laboratories in doing the measurement. As PT provider, Chemical Metrology Laboratory held annual PT round since 2013. In 2018 PT round, the Chemical Metrology Laboratory provided a PT to measure the electrolytic conductivity of synthetic wastewater. Before preparing the PT test samples, the feasibility study was conducted to determine the best formulation of synthetic wastewater. During this study, two different formulations were compared in terms of simplicity formulation, electrolytic conductivity value, total dissolved solid/electrolytic conductivity conversion value, homogeneity and stability of the synthetic wastewater. The results show that both candidates are sufficient to be used as PT test samples; however, only one candidate was selected due to its ease and simplicity formulation.

Eleventh Aegean Analytical Chemistry Days (AACD2018), Chania, Crete, Greece, 25–29 September 2018

The Eleventh Aegean Analytical Chemistry Days (AACD2018) was held in Chania, Crete, Greece during the period from 25 to 29 September 2018. The scientific framework consisted of 13 oral sessions and 2 poster sessions. Papers in fields such as atomic and molecular spectrometry, mass spectrometry, bioanalytical and clinical analysis, chromatography and separation techniques, electroanalytical methods and biosensors, speciation analysis, sample preparation, chemometrics, quality control/quality assurance and chemical metrology, environmental analysis, food analysis and pharmaceutical analysis were presented during this five-day conference. The social program included a visit to the Botanical Park of Chania and dinner with Cretan dishes and a post-conference one-day excursion to Knossos and Herakleio. During the closing ceremony, it was announced that the next AACD will be organized in Turkey by Professor Sezgin Bakirdere at Yildiz Technical University, Istanbul.

Purity assessment using the mass balance approach for inorganic in-house certified reference material production at Inmetro

The production of Certified Reference Materials (CRMs) is one of the essential activities of the National Institute of Metrology, Quality and Technology (Inmetro) to ensure metrological traceability of inorganic elemental measurements in Brazil. This work presents a set of procedures for purity assessment and in-house certification of high-purity salts, implemented at the Laboratory of Inorganic Analysis, from the Chemical and Thermal Metrology Division at Inmetro. We developed and validated methodologies based on inductively coupled plasma mass spectrometry, energy-dispersive X-ray fluorescence spectrometry and inductively coupled plasma optical emission spectrometry measurements with standard addition calibration in order to determine the mass fraction of up to 71 elements considered as possible impurities. The purity of inorganic salts was determined using the mass balance approach with expanded measurement uncertainties smaller than a mass fraction of 0.007 %. All procedures were performed according to the ISO 17034:2016 standard. The CRMs will be used for the production and certification of single-element calibration solutions at Inmetro.

Establishment of measurement traceability for peptide and protein quantification through rigorous purity assessment—a review

The health of their populations and efficient health care systems are of critical importance to the economic and social well-being of nations. Accurate and comparable peptide/protein measurements are required in support of diagnosis, prognosis, monitoring and treatment of widespread diseases (e.g. diabetes). The required consistency of measurement results can be achieved by making them traceable to stated references and through the development of Reference Measurement Systems. The review mainly concentrates on the progress made in the Protein Analysis Working Group of the Consultative Committee for Amount of Substance: Metrology in Chemistry and Biology (CCQM-PAWG) in establishing Primary Calibration Reference Services in the emerging area of health markers such as peptides/proteins. Primary Calibration Reference Services are technical capabilities for composition assignment, commonly as the mass fraction content, of pure substances or solutions thereof. It is a core technical competency for National Measurement Institutes (NMIs). A limited number of key comparisons, foreseen by the CCQM-PAWG strategy, are discussed that enable NMIs providing measurement services in peptide/protein analysis to test and demonstrate their capabilities. In addition, the review examines the development and improvement of analytical methods and metrological models that are required to meet the needs of NMIs and associated clinical stakeholders.

Advances in reference materials and measurement techniques for greenhouse gas atmospheric observations

We present the global research landscape which aims to deliver a measurement infrastructure to underpin atmospheric observations of key greenhouse gases governing changes in the Earth’s climate. These measurements present a significant challenge to the metrological community, analytical laboratories and major producers of reference materials. The review focuses on the progress made in the Gas Analysis Working Group of the Consultative Committee for Amount of Substance: Metrology in Chemistry and Biology (CCQM-GAWG) in establishing the primary realisation of the amount-of-substance fraction for carbon dioxide, methane and nitrous oxide in an air matrix. It also focuses on the importance of providing traceable measurements of isotopic composition of these components for commutability of reference materials and for isotope ratio measurements for greenhouse gas source attribution. The review examines the developments in the Global Atmosphere Watch (GAW) Programme of the World Meteorological Organization (WMO) for providing the framework for the development and implementation of integrated greenhouse gas observations, which is vital for understanding the global carbon cycle and the role greenhouse gases play in climate change. The developments in analytical techniques are also discussed which have shaped the direction of the metrology required to meet the evolving and future needs of stakeholders.

The role of ICP-MS in inorganic chemical metrology

ICP-MS has played a key role in inorganic chemical metrology for 25 years, from the 1993 CIPM feasibility study which led to establishment of the CCQM. Since that time, the Inorganic Analysis Working Group of the CCQM has organised 56 international comparisons involving measurements by ICP-MS and, in a recent comparison, 16 different national institutes submitted their results using the technique. Metrological applications of ICP-MS currently address an enormous range of measurements using a wide variety of instrumentation, calibration strategies and methodologies. This review provides an overview of the ICP-MS field with an emphasis on developments which are of particular relevance to chemical metrology. Examples from CCQM comparisons and the services available from the participants are used to illustrate how the capability and scope of ICP-MS methods have expanded far beyond the expectations of 1993. This is due in part to the research and development programmes of the national institutes which participate in the CCQM. They have played a key role in advancing new instrumentation and applications for elemental analysis, isotope dilution mass spectrometry, determination of isotopic ratio or composition, and speciation of organometallic compounds. These developments are continuing today, as demonstrated by work in new fields such as heteroatom quantitation of proteins, characterisation and counting of nanoparticles using spICP-MS, and LA-ICP-MS analysis of solid materials.

Metrological advances in reference measurement procedures for electrolytic conductivity

The Working Group on Electrochemical Analysis and Classical Chemical Methods (EAWG) of the Consultative Committee for Amount of Substance: Metrology in Chemistry and Biology conducts regular pilot studies and key comparisons to ensure international consistency of electric conductivity measurement results of electrolyte solutions with an uncertainty of around 0.02% at the highest level. Apart from supporting the international calibration infrastructure, comparison measurements have also been used to investigate specific metrological issues related to conductivity measurements which will be reviewed in this paper. First, two different metrological references coexist for conductivity measurements, namely the SI and recipe-based primary conductivity standards, the implications of which will be discussed. Furthermore, pilot study P142 and subsequent investigations by an EAWG expert group have revealed significant inconsistencies in the equivalence of conductance ratios. Such conductance ratios are the basis for assigning conductivity values to secondary standards and conductivity measurements in the field. The activities of the EAWG to investigate this fundamental issue will be reviewed. Finally, the metrological support for conductivity measurements of new kinds of conductivity standards will be outlined.

UNCERTAINTY ESTIMATION FOR THE MEASUREMENT OF ELECTROLYTIC CONDUCTIVITY BY SECONDARY METHOD USING CELL TYPE D

Electrolytic conductivity measurement is one of the important parameters to evaluate the concentration of dissolved substances in a solution and has been widely used in various fields of life, science, and technology. It was being used for process control and quality assurance. The traceability of the measuring results is a crucial requirement to guarantee reliability. The electrochemistry laboratory - chemical metrology Indonesia has started to develop a secondary method for electrolytic conductivity measurement. The objective of this work is to provide a traceability chain for electrolytic conductivity measurement in Indonesia through secondary reference material of Potassium Chloride (KCl) 1 M. The secondary reference material of KCl 1 M can be used as a standard for calibrating the conductivity meter, especially in seawater analysis. The secondary reference material that is developed has an electrolytic conductivity value of about 111 mS/cm and was measured using cell type D from ZMK, Germany. This cell is made from glass with two platinization electrodes inside. The distance of the electrodes is 60 mm, and the diameter of the electrode is 20 mm. The uncertainty measurement was estimated according to the ISO GUM recommendation by identifying all possible uncertainty sources in the electrolytic conductivity measurement process. The result showed that the expanded uncertainty of electrolytic conductivity measurement for KCl 1 M by a secondary method using cell type D was 0.33% at k=2 for 95% confidence level with a repeatability of the measurements and cell constant as the biggest sources of uncertainty which contributed as 80% and 17%, respectively.

Final Report on Key Comparison SIM.QM-K27: Ethanol in Aqueous Matrix

Within the SIM RMO, certain NMIs/ DIs have indicated the need to demonstrate their measurement capability for the determination of ethanol in aqueous matrices. Reflecting upon the current situation, the SIM Chemical Metrology Working Group (CMWG) conducted a second regional Key Comparison in 2016 linked to the CCQM-K27, SIM.QM-K27. The RMO Key Comparison SIM.QM-K27 was coordinated by INMETRO, who demonstrated capability in the CCQM-K27.2 subsequent study: determination of ethanol in aqueous media. INMETRO also coordinated the first SIM RMO Key Comparison SIM.QM-K1. For SIM.QM-K27, two levels of ethanol in water solutions were gravimetrically prepared by INMETRO with a concentration range between 0.5 mg/g and 5 mg/g. The gravimetric value of the aqueous ethanol solutions was used to link SIM.QM-K27 to the CCQM-K27 Key comparison reference value (KCRV). The gravimetric values for SIM.QM-K27 Level 1 and Level 2 were (0.814 ± 0.008) mg/g (U k =2 ) and (3.818 ± 0.038) mg/g (U k =2 ), respectively. The KCRV was determined using the purity-corrected gravimetric preparation values. The KCRV uncertainty was assigned as 1 % from the reference values in order to give the same uncertainty as in the CCQM-K27.2 comparison. Fourteen laboratories took part in this regional KC, from SIM and other RMOs. One participant (INACAL) did not send results and thus it's capability was not evaluated. Ten of the thirteen participants in the SIM.QM-K27 demonstrated their ability to measure ethanol in aqueous matrix in the concentration range of 0.5 mg/g to 5 mg/g (both levels). One participant (ISP) demonstrated its ability to measure ethanol in aqueous matrix only at the low level (0.5 to 1.5 mg/g) and another participant (INM) demonstrated its ability to measure ethanol in aqueous matrix only at the high level (1.5 to 5.0 mg/g). NIMT did not demonstrate its ability to measure ethanol in aqueous matrix from 0.5 mg/g to 5 mg/g (both levels). The abilities demonstrated by the participants should be indicative of their ability to provide reference measurements for ethanol content in aqueous samples for both forensic and commodities applications. This report presents the results of the SIM Key comparison SIM.QM-K27. Successful participation in SIM.QM-K27 demonstrates the following measurement capabilities in determining mass fraction of ethanol in mass fraction range from 0.5 mg/g to 5 mg/g in an aqueous matrix.KEY WORDS FOR SEARCHKey comparison and ethanol in waterMain textTo reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Proficiency testing for pH measurements: a 3-year evaluation

Chemical Metrology Laboratory, LIPI, organizes an annual proficiency testing (PT) scheme with pH being one of the parameters investigated. This study presents and evaluates the performance of the laboratories that participated in the pH measurement during 3 consecutive years of the PT from 2014 to 2016. The PT test items were prepared by Chemical Metrology Laboratory, LIPI, from high-purity material. The homogeneity testing and stability testing of the PT test items were performed according to ISO 13528:2005. The measured reference value was directly traceable to the pH value of SRM® 185i and 187e produced by NIST, USA, and the expanded uncertainty was calculated according to ISO GUM:2008 with a coverage factor (k = 2), at a 95 % confidence level. Individual laboratory performance was reported in terms of z-scores. In the 2014 scheme, the reference buffer solution was not provided by provider, while in the 2015 and 2016 schemes, reference buffer solutions were distributed to participants alongside the PT test items. The best performance was achieved in 2015, where more than 90 % of the reported results were assessed as satisfactory. The laboratory performance in 2015 coincided with the distribution of two traceable pH standard solutions to participants which allowed them to satisfactorily calibrate their instrumentation. In conclusion, regular PT program is an effective way of demonstrating the effectiveness of quality assurance procedures applied in participating laboratories and provides opportunity for corrective action which will benefit measurements made in the future.

Competency evaluation on electrolytic conductivity measurement in Indonesia by an unofficial bilateral comparison between RCChem-LIPI and NIMT

The Research Centre for Chemistry—Indonesian Institute of Sciences (RCChem-LIPI) organized an unofficial bilateral comparison on electrolytic conductivity with the Electrochemistry Laboratory—National Institute of Metrology Thailand (NIMT). The electrochemical laboratory RCChem-LIPI, as a Designated Institute for Chemical Metrology in Indonesia, started to develop the secondary method on electrolytic conductivity measurement in 2016. Therefore, the purpose of this unofficial bilateral comparison was to test the ability of RCChem-LIPI laboratory and see the capacity building progress in doing the conductivity measurement. There were two samples containing potassium chloride prepared by RCChem-LIPI, and both samples had the electrolytic conductivity value in the range of 1000 µS cm−1 to 20000 µS cm−1. The samples were sent to NIMT and then measured at the same time duration. The results were compared, analyzed and evaluated based on their assigned values. The assigned values were 15309 µS cm−1 and 6650 µS cm−1 for samples A and B, respectively. The deviation for each measurement result was determined, and the uncertainties were also calculated from the data reported by both laboratories. The data evaluation and analysis confirm that the measurement results for both participant laboratories were in agreement with the assigned value of this unofficial bilateral comparison.

The Consultative Committee for Metrology in Chemistry and Biology – CCQM

The Consultative Committee for Metrology in Chemistry and Biology – CCQM

Quantifying Uncertainty in Analytical Measurements

In providing chemical, biochemical and agricultural materials testing services for quality specification, the analytical chemists are increasingly required to address the fundamental issues related to the modern concepts of Chemical Metrology such as Method Validation, Traceability and Uncertainty of Measurements. Without this knowledge, the results cannot be recognized as a scientific fact with defined level of acceptability. According to ISO/IEC 17025:2005, this is an essential requirement of all testing laboratories to attain competence to test materials for the desired purpose. of these three concepts of chemical metrology, the most complex is the calculation of uncertainties from different sources associated with a single measurement and incorporate them into the final result(s) as the expanded uncertainty(UE) with a defined level of reliability (e.g., at 95% CL). In this paper the concepts and practice of uncertainty calculation in analytical measurements are introduced by using the principles of statistics. The calculation procedure indentifies the primary sources of uncertainties and quantifies their respective contributions to the total uncertainty of the final results. The calculations are performed by using experimental data of Lead (Pb) analysis in soil by GF-AAS and pesticides analysis in wastewater by GC-MS method. The final result of the analytical measurement is expressed as: Result (mg/kg) = Measured Value of Analyte (mg/kg) ± Uncertainty (mg/kg), where the uncertainty is the parametric value associated with individual steps in measurements such as sample weighing(Um), extraction of analyte (Ue) (Pb from soil or pesticides from water), volumetry in measurement (Uv), concentration calibration(Ux), etc. The propagation of these individual uncertainties from different sources is expressed as combined relative uncertainty (Uc), which is calculated by using the formula:Combined uncertainty Uc/c = {(Ux/x)2+(Um/m)2+(Uv/v)2+(Ue/e)2+…}1/2The overall uncertainty associated with the final result of the analyte is expressed as Expanded Uncertainty (UE) at certain level of confidence (e.g. 95%). The Expanded Uncertainty is calculated by multiplication of Combined Uncertainty (Uc) with a coverage factor (K) according to the proposition of level of confidence. In general, the level of confidence for enormous data is considered at 95%, CL where K is 2. Hence, the final result of the analyte is expressed as: X ± UE (unit) at 95% CL, where UE = 2Uc.Journal of Bangladesh Academy of Sciences, Vol. 41, No. 2, 145-163, 2017

Final report for CCQM-K86.b relative quantification of Bt63 in GM rice matrix sample

A key comparison CCQM-K86.b was performed to demonstrate and document the capacity of National Metrology Institutes (NMIs) and Designated Institutes (DIs) in the determination of the relative quantity of two specific genomic DNA fragments present in a rice powder. The study provides the support for the following measurement claim: "Quantification of the ratio of the number of copies of specified intact sequence fragments of a length up to 150 nucleotides following extraction from an unprocessed, high starch ground seed matrix, with a copy number ratio from 0.005 to 1". The study was carried out under the auspices of the Nucleic Acids Working Group (NAWG) of the Consultative Committee for Amount of Substance: Metrology in Chemistry and Biology (CCQM) and was jointly coordinated by the National Institute of Metrology, China (NIMC) and Government Laboratory Hong Kong (GLHK).The following laboratories (in alphabetical order) participated in this key comparison study: CENAM (Mexico); GLHK (Hong Kong); LGC (United Kingdom); NIB (Slovenia); NIMC (P.R. of China); NIMT (Thailand); NMIA (Australia); NMIJ (Japan); TÜBITAK-UME (Turkey). Good agreement was observed between the reported results.KEY WORDS FOR SEARCHGenetically modified (GM) crops, digital PCR, copy number ratio, GM riceMain textTo reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Calibración de espirómetros por vía húmeda en LATU y su adaptación a la ley de “alcohol cero”

The following paper describes the work carried out by the Chemical Metrology Department to develop the first national breath analyser calibration service according to the recommendation from the International Organization of Legal Metrology, OIML R126:2012(E) (OIML, 2012). A detailed account of the different stages of this process is given, from method validation to the production of Certified Reference Materials of ethanol in water to be used as standards. In addition, a detailed description of the modifications introduced as a consequence of the "zero alcohol" law established in 2016 is presented, in order to demonstrate the applicability of the proposal to the requirements established in the recommendation.

Participation of RCChem–LIPI in the Key Comparison APMP.QM-K91 for pH Measurement of Phthalate Buffer

Metrology in Chemistry (MiC) Laboratory of Research Center for Chemistry, Indonesian Institute of Sciences (RCChem–LIPI) has been participated in key comparison APMP.QM-K91 for the pH measurement in phthalate buffer. This participation is indispensable for supporting the Calibration and Measurement Capabilities (CMC) claim in the field of pH measurement. The method used in this measurement was validated using differential potentiometry cell method and the pH measurements were performed at 15, 25 and 37 °C. The results of RCChem-LIPI in this key comparison were satisfied with the degree of equivalence (Di) and uncertainty of degree of equivalence (uDi) was in agreement with the key comparison reference value (KCRV). It demonstrates the capability of MiC Laboratory of RCChem-LIPI in measuring the pH of phthalate buffer, which is crucial in obtaining the CMC claim.

Final report of the SIM.QM-S7 supplementary comparison, trace metals in drinking water

SIM.QM-S7 was performed to assess the analytical capabilities of National Metrology Institutes (NMIs) and Designated Institutes (DIs) of SIM members (or other regions) for the accurate determination of trace metals in drinking water. The study was proposed by the coordinating laboratories National Research Council Canada (NRC) and Centro Nacional de Metrologia (CENAM) as an activity of Inorganic Analysis Working Group (IAWG) of Consultative Committee for Amount of Substance - Metrology in Chemistry and Biology (CCQM). Participants included 16 NMIs/DIs from 15 countries. No measurement method was prescribed by the coordinating laboratories. Therefore, NMIs used measurement methods of their choice. However, the majority of NMIs/DIs used ICP-MS.This SIM.QM-S7 Supplementary Comparison provides NMIs/DIs with the needed evidence for CMC claims for trace elements in fresh waters and similar matrices.Main textTo reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Full method validation in clinical chemistry

Clinical chemistry is subject to the same principles and standards used in all branches of metrology in chemistry for validation of measurement methods. The use of measuring systems in clinical chemistry is, however, of exceptionally high volume, diverse and involves many laboratories and systems. Samples for measuring the same measurand from a certain patient are likely to encounter several measuring systems over time in the process of diagnosis and treatment of his/her diseases. Several challenges regarding method validation across several laboratories are therefore evident, but rarely addressed in current standards and accreditation practices. The purpose of this is paper to address some of these challenges, making a case that appropriate conventional method validation performed by the manufacturers fulfils only a part of the investigation needed to show that they are fit for purpose in different healthcare circumstances. Method validation across several laboratories using verified commercially available measuring systems can only be performed by the laboratories—users themselves in their own circumstances, and need to be emphasised more by the laboratories themselves and accreditation authorities alike.

8th Brazilian Congress on Metrology (Metrologia 2015)

THE EIGHTH BRAZILIAN CONGRESS ON METROLOGY (METROLOGIA 2015)The United Nations celebrated 2015 as the International Year of Light. By a curious coincidence, many notable events in science and technology completed a multiple of 50 or 100 years in 2015. From the pioneering work of the wise Ibn Al-Haytham in 1015, through Fresnel, Maxwell, Einstein, the discovery of the cosmic microwave background, to the use of optical fibres in communications in 1965.Electromagnetic radiation is present in our daily lives in countless applications. It is remarkable that there is no way to think about these applications without thinking of measurements. From entangled photons to more prosaic public illumination of our daily life, we are intrinsically connected all the time with the luminous phenomena. Among other things, the light allows global communication on a large scale. It strengthens the internationalization of production processes, which brings considerable changes in relations, processes and economic structures, as well as it orients the social, political and cultural behaviour of any country. These conditions of this internationalization require interchangeability of parts of complex systems, translated into strict adherence to the standards and specifications that use increasingly accurate measurement techniques, as well as the growing demand from consumer markets for products and higher quality services. They also require innovation and improvements in domestic production to boost the competitiveness of industries in domestic and foreign markets. Thus, if the Science of Measurements is taken as a serious concern, countries are better prepared to evolve towards economic and social development.In this 8th edition of the Brazilian Congress on Metrology (METROLOGIA 2015), in addition to the thematic sessions in various areas of Metrology and Conformity Assessment, we hold several satellite events. They are already traditional events or highlight important current issues such as those relating to the International Year of Light. The events are meetings on Electricity (XI International Seminar on Electrical Metrology - SEMETRO), Ionizing Radiation (II Brazilian Congress on Ionizing Radiation - CBMRI) and the Meeting of the Brazilian Chemical Metrology Network (REMEQ).As in previous events, we hosted the Expo Metrology 2015 trade show and an exhibition of measuring equipment. During the conference, short courses in various areas of interest in Metrology and Conformity Assessment were given, organized by the Basic Industrial Technology National School - ENTIB, an initiative from the Brazilian Society of Metrology (SBM).The 8th Brazilian Congress on Metrology consisted of Keynote Speeches (6) and regular papers (292). Among the regular papers, the 100 most outstanding ones, comprising a high quality content on Metrology, were selected to be published in this issue of the Journal of Physics: Conference Series.With tremendous satisfaction and gratefulness, the organizers of METROLOGIA 2015 would like to present this volume of IOP Journal of Physics: Conference Series (JPCS) to the scientific community to promote further research in Metrology. We believe that