Participation of Accredited Laboratories in Proficiency Testing Schemes and Interlaboratory Comparisons

Abstract

This paper presents the elements of metrology laboratory accreditation for calibration in the scope of calibration E-05 Dimensions, and calibration for the subject: the distance and angle measures. During the accreditation, but also in its maintenance, calibration laboratories must prove their competence. Each laboratory must have the quality management procedures for monitoring the validity of the calibrations performed. This monitoring shall be planned and reviewed through: internal quality control, participation in the interlaboratory comparisons or proficiency testing schemes, repeated calibrations using the same or different methods, re-calibration of the saved samples and correlation of results for different characteristics of the sample. According to the ISO/IEC 17025:2005 standard, competence is proved by participating in interlaboratory comparisons or participation in Proficiency testing (PT) schemes. This paper aims to stimulate discussion and debate about ways of proving competence of calibration laboratories. We believe that, in the interpretation of ISO/IEC 17025, the laboratory can demonstrate competence by participating in any activity, PT schemes or interlaboratory comparisons, and they are equal to this need. The procedure and the results of the interlaboratory comparisons between two accredited laboratories will be described.

UV-Vis Spectroscopic Characterization of Nanomaterials in Aqueous Media

“…Likewise, during the shipping process, the aliquoted samples should be kept cold, as long periods at room temperature may lead to significant aggregation 20 . Additionally, to overcome failures in NM characterization, it is necessary to provide access to the original data, protocols, and key research materials between collaborating labs, especially, when assessing the proficiency, consistency, and reliability through an ILC 15 . Making these factors clear and accessible is key to achieving a successful NM characterization by any laboratory or equipment.…”

“…Making these factors clear and accessible is key to achieving a successful NM characterization by any laboratory or equipment. Disregarding these aspects might result in a lack of reproducibility, accuracy, and misleading or erroneous results 15 . Although UV-Vis spectroscopy has been demonstrated to be the gold standard in NM characterization, it can be exploited in many other fields as it allows quantitative determination of an extended dynamic range of solutions in both inorganic and organic compounds 6 , 21 .…”

“…The absorbance is calculated as the ratio between the intensity of a reference sample (I 0 ) and the unknown sample (I), as described in the following equation 14 : The simplicity of UV-Vis makes it an ideal technique to compare PTS of an established measurement protocol 6 , 12 , 15 . The objective of an ILC or PTS is to verify the performance and reproducibility of a method using an SOP 15 . This, in turn, provides a standardized approach for quick characterization of nanoparticle suspensions for other users.…”