Chemical Metrology

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INTRODUCTION

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The Chemical Metrology Laboratory develops, maintains and disseminates gas and particle metrology related national measurement standards in Singapore. NMC has set up and is continuously improving national standards through R&D activities in this area to better meet the need of the industry. We have also participated in international comparisons to ensure our gas and particle standards are equivalent to those of other countries.

LATEST NEWS

NMC has developed new capabilities on the chemical metrology area:

  • NMC is developing new measurement method for the determination of polymer bio-degradability.
  • NMC has improved Archimedes method for better accuracy density measurement for 3D printed parts.
  • Particle mass, size and shape measurement capabilities for liquid suspension, powder and aerosol form particles.
  • Airborne particle count measurement capabilities for calibration of counting efficiency of particle counters which is used for air quality and clean room monitoring. The coverage is up to 5 micron in particle diameter, with expanded uncertainty of 4% - 9%.
  • Precise measurements of stable isotope of carbon, nitrogen, sulphur, oxygen, and hydrogen using stable Isotope Ratio Mass Spectrometer (IRMS) system. The IRMS system can be used for identifying sources of air pollutants and greenhouse gases, compounds of natural gases, and providing fingerprint for food authenticity and food integrity.

MEASUREMENT STANDARDS AND DISSEMINATION

The Chemical Metrology Laboratory develops, maintains and disseminates gas related national measurement standards and gas related Primary Reference Material (PRM) and Certified Reference Materials (CRM)  in Singapore in the areas of automotive gases, greenhouse gases, natural gases, ground level ozone, element isotope analysis, purity analysis, etc. These measurement standards are also developed for measurement and verification of related gas sensors and analysers for indoor/outdoor air quality, industry emission and climate change monitoring. These standards are derived from base unit of mole. Meanwhile, Chemical Metrology Laboratory also built up the measurement capabilities of particle mass, shape and size, particle count and isotope analysis.

 

Certified Reference Materials

Chemical Metrology Laboratory has been producing primary gas standards using the gravimetric method and gas standard verification according to ISO 6142-1, ISO 6143-2001, ISO 17034:2016 and ISO/IEC 17025. We are able to prepare and verify binary and multi gas component mixtures in different concentration ranges. These gas mixtures can be used for calibrating reference standards used for indoor & outdoor air quality, car & ship emissions, and industry emissions. Some common gases mixtures include methane (CH4), carbon dioxide (CO2), carbon monoxide (CO), argon (Ar), oxygen (O2), propane (C3H8), nitrogen (N2), and sulphur dioxide (SO2).

Services provided:

  • Verification of gas mixtures concentration

Ozone Analyser

Ground-level ozone concentration is an important air quality parameter which is monitored and reported worldwide. Chemical Metrology Laboratory has established and maintained a Standard Reference Photometer (SRP) as our primary ozone standard. Our SPR has participated at the ongoing key comparison BIPM.QM-K1 and compared well with other national primary ozone standards from different National Metrology Institutes, including National Institute of Standards and Technology (NIST), National Physical Laboratory (NPL).  The operating principle of SRP is based on UV photometry and has been designed for the production and measurement of ozone concentrations in air up to 500 nmol/mol.

Services provided:

  • Calibration of ozone analysers

Gas Sensor and Analyser

We have developed gas detector and analyser calibration capability. Our report is compliant to iso 17025. Our measurement is traceable to our gas mixture standards and SI unit. Our gas mixture include O2/N2, CO2/N2, CH4/N2, C3H8/N2, etc.

Services provided:

  • Calibration of gas detectors and gas analysers

Purity Analysis

Chemical Metrology Laboratory has developed the capability of purity analysis for pure gases like nitrogen, oxygen, helium, carbon dioxide, carbon monoxide, methane and propane by using Gas Chromatography - Flame Ionized Detector (GC-FID) and Gas Chromatography - Pulsed Discharged Helium Ionization Detector (GC-PDHID). The core impurities analysis includes nitrogen, oxygen, hydrogen, helium, carbon dioxide, carbon monoxide, methane and other hydrocarbons. The low detection limits (LDL) of core impurities are 50 ppb of nitrogen, oxygen, hydrogen, helium, carbon dioxide, carbon monoxide, and 100 ppb of methane and other hydrocarbons.

Services provided:

  • Purity analysis of pure gases

Particle Measurement

Chemical Metrology Laboratory has developed airborne particle count measurement capabilities for calibration of counting efficiency of particle counters which is used for air quality and clean room monitoring. The coverage is for 0.3 - 5 micron in particle diameter, with expanded uncertainty of 4% - 9%. Our report is compliant to ISO 17025. Our measurement in particle counting is traceable to SI unit. We has also developed facilities for microparticle size and shape measurement for airborne, liquid-borne and powder samples, and the capabilities in single nanoparticle mass and density measurement for liquid samples.

Services provided:

  • Calibration of counting efficiency of particle counters
  • Particle size and shape measurement
  • Single nanoparticle mass and density measurement

Chemical and Material Characterization

Chemical Metrology Laboratory is also proactively working on the development of new measurement methods and solutions, including water quality measurement (total organic carbon, chemical oxygen demand, microplastics, and etc.), food nutrition detection and measurement, packaging material testing (polymer degradability, particle leaching, gas penetration and etc.), and additive manufacturing powder and parts measurements (Density of 3D printed parts, Powder flowability, and etc.)

Services provided:

  • Improved Archimedes method for density measurement of 3D printed parts
  • Bio-degradation measurement of soluble and insoluble polymers

    TRAINING COURSES

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    The Chemical Metrology Laboratory provided training course on measurements Indoor Air Quality which is based on SS 554 requirements and Green Building’s requirements. Participants could gain the concepts and practical knowledge in parameters and measurements of Indoor Air Quality, including suitable IAQ equipment selection, IAQ equipment calibration, measurement methods, gas mixture standards needed, uncertainty evaluation. The training also provided an opportunity of to participants for onsite training of gas analysis and IAQ equipment calibrations in gas lab.

    Trainings conducted in the past:

    • MAP course Gas analysis

    INTERNATIONAL COMPARISONS

    NMC is currently the observer in the Consultative Committee for Amount of Substance – Metrology in Chemistry (CCQM) and also the active member in the Asia Pacific Metrology Programme (APMP) Technical Committee and Gas Analysis Working Group (GAWG) for preparation and analysis of gas mixtures. To ensure the metrological traceability, recent years the Chemical Metrology Laboratory participated in international comparisons as shown in the below table.

    International measurement standards:

    • BIPM ongoing Key Comparison (Ozone at ambient level from 0 to 500 nmol/mol)
    • EURAMET International Comparison (Carbon dioxide at 3 × 10-2 mol/mol)
    • BIPM ongoing Key Comparison (Ozone at ambient level from 0 to 500 nmol/mol)
    • APMP supplementary comparison on Methane (CH4) at 2000 ppm Concentration
    • APMP supplementary comparison of oxygen in nitrogen at 0.2 mol/mol level
    • APMP comparison of 1000 ppm propane in nitrogen
    • APMP supplementary comparison 100 ppm Carbon Monoxide in nitrogen
    • APMP supplementary comparison 1000 ppm Carbon Dioxide in nitrogen
    • BIPM ongoing Key Comparison (Ozone at ambient level from 0 to 500 nmol/mol)
    • COOMET key comparison of Carbon dioxide in Air at urban level (480‐800) µmol/mol

    RESEARCH PROJECTS

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    The Chemical Metrology Laboratory carries out R&D and consultancy for industry and IHLs to develop and apply gas and gas sensor measurement techniques for the applications including industry pollutions, air quality, green building, workplace safety, additive manufacturing and gas leakage, etc.

    Some of the projects in GL laboratory:

    • Chemical Metrology Program
    • Photonic Gas Sensor
    • Real-time Monitoring and Characterization of Particle Count and Indoor Environmental Environmental Quality with Integrated Low-cost Sensors
    • Development of Chip-scale Mid-IR Photonics Gas Sensor for Indoor Air Quality Monitoring 
    • Mechanical and Fatigue Characteristics of 3D printed Titanium Implants
    • Mechanical and Fatigue Characteristics of 3D Printed Polymeric Prosthetics for Medical Applications
    • MSC Exosome Characterization
    • Sensitivity of Thermal Camera for Hydrocarbon Gas

    INTERESTING STORIES

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    What is good ozone and bad ozone?

    The good ozone is the stratospheric ozone layer occurring in the upper atmosphere, which extends from about 6 km to 50 km above the earth’s surface. The good ozone protected us from the sun’s harmful ultraviolet (UV) radiation. The bad ozone is the ground-level ozone in the troposphere, which is harmful to human and plants. Bad ozone is created when primary pollutants, such as nitrogen oxides and volatile organic compounds, react in the presence of sunlight.