Calibration Gases for Individual Purposes
The highest demands are placed on gas mixtures when they are used for the operation of sensitive analytical instruments in quality assurance, safety technology, emission or environmental monitoring. Most of the analytical instruments in use today operate comparatively, like the balance scales often seen in street markets in the old days. Just as these required precise weights in order to weigh correctly, modern analytical instruments use high precision gas mixtures with defined compositions for calibration.
As the accuracy of the analytical results critically depends upon the accuracy of the used calibration gases, Messer follows a strict quality management system in order to ensure the highest quality standards in the production of calibration gases.
Gas Mixture Composition
The composition of calibration gases varies from application to application - this ranges from simple binary mixtures in the %-range to multicomponent mixtures in the ppm- or even ppb-range. Due to the nearly unlimited range of possible mixtures, Messer produces most calibration gases as individual gas mixtures according to customer specifications.
The individual gas mixtures are characterized by their detailed composition, expressed in an agreed unit, the production tolerance, the uncertainty of the certified composition and the stability period. Adapted to the different customer requirements, Messer offers calibration gases in various categories.
Gas Mixture Categories
In most applications in measurement techniques, a calibration gas uncertainty of +/- 2% rel. is used. We offer these as Labline mixtures, usually with a production tolerance in the range of +/- 5% rel. For high precision measurements, we recommend calibration with Topline mixtures with an uncertainty of less than +/- 1% rel.. Labline and Topline mixtures can be produced with a wide range of different components in the %- and ppm-range. For trace analysis, for example in environmental monitoring, Messer offers Traceline mixtures with concentrations in the ppb-range.
Each calibration gas is supplied with a certificate of analysis (according to EN ISO 6141). Besides the rated and actual composition and its uncertainty and other technical data, the expiration date is also stated on the certificate. The standard stability period of calibration gases is 1 year. Depending on the chemical properties of the components and the concentration range, Messer also offers many calibration gases with a prolonged stability period of up to 5 years (Longlife-option).
Accredited Gas Mixtures – Calibration Gases of Highest Quality Level
Messer continuously assures the highest quality of produced calibration gases by applying a strict quality management. Besides the general quality management system according to the EN ISO 9000 family, the standard EN ISO/IEC 17025 (General requirements for the competence of testing and calibration laboratories) covers the specific requirements of a laboratory. The main provisions concern the operation and the scope of a quality management system as well as the evidence of the necessary technical competence for performing calibration.
Messer runs several laboratories accredited according to EN ISO/IEC 17025 and can offer a wide range of mixtures with a certificate from an accredited laboratory (Accredited mixture EN ISO/IEC 17025). The essential quality features of such gas mixtures are the traceability of gas mixtures´ composition to national standards and determination of the uncertainty in accordance with a recognized method.
Messer recommends the use of accredited calibration gases, if compliance with legal obligations (e.g. control of emission) is to be verified or if the laboratory itself holds an accreditation.
With the additional accreditation according to EN ISO 17034 (General requirements for the competence of reference material producers), the laboratory achieves the recognition, that it meets the highest quality and competence requirements, necessary for the production of certified reference materials. Certified reference materials (CRM’s) play an important role in analytical chemistry as they provide reference points of the highest metrological level.
Messer’s Swiss production plant holds the accreditation according to EN ISO 17034. Therefore, Messer can also offer a defined scope of certified reference materials.