Vol.2 No.1 2009

16/88

Research paper−13−Synthesiology - English edition Vol.2 No.1 pp.13-24 (Jun. 2009) required for individual analytes. In this type of analysis, the accuracy of inspection and testing results are crucial, and the reliability of the “yardstick” is of paramount importance. The use of certified reference materials (CRMs)Term 3, [1] or equivalent RMs is highly recommended in such cases, and therefore various testing and inspection laboratories are working swiftly to acquire the RMs necessary to handle the ever-increasing list of regulated materials.2 Current problems with RMsThe characterization of RMs by metrologically appropriate procedures is achieved by using measurement methods that offer traceabilityTerm 4 to SI definitions (in this case, amount-of-substance). Normally, this is a task performed by the national metrology instituteTerm 5 of a country, and the RMs produced are known as the national reference materials (primary RMs). Generally, national RMs offer the highest standards of accuracy, and are scrupulously prepared with labor, time, and expense. Normally, they are not transferred directly to the inspection and testing laboratories that perform the actual analysis, because this is not practical due to the quantities and costs involved. Instead, secondary RMs are calibrated based on the national RMs, and working RMs are in turn calibrated using the secondary RMs. In this way, a pyramid structure is constructed, with few higher-order RMs at the top and a larger population of lower-order RMs reproduced below. Order in this proliferation of RMs is enforced through traceability to the original set of accurate “yardstick” or the national RMs. In essence, this concept is similar to the traceability systems where scales are calibrated using a series of weights, and the current RM traceability 1 IntroductionOur modern lives are surrounded by chemical compounds, and a wide range of laws and regulations controls these chemical compounds, to ensure safety and to prevent adverse impact on the environment and human health. In recent years, public concern for safety has increased in Japan, prompting an increase in the number of chemical compounds subject to regulation, limitations, and other regulatory controls. For example, in May 2006, the Food Sanitation Law was revised to introduce the “Positive List SystemTerm 1” for agricultural chemical residue in foods. With the enforcement of stringent regulations, the number of control subjects expanded from approximately 250 to about 800 kinds of agricultural and other chemical compounds traded domestically and internationally. At the same time, several new Official Methods of AnalysisTerm 2 were established to measure the regulated chemical compounds, and as result, the use of advanced analytical equipment capable of conducting multiple simultaneous measurements, such as gas chromatograph/mass spectrometer (GC/MS) and liquid chromatograph/mass spectrometer (LC/MS), increased in food and environmental analyses. In this situation, many laboratories that inspect and test chemical compounds are increasingly employing GC/MS and LC/MS to conduct analyses.While these analytical equipment are capable of simultaneously measuring multiple components, it is necessary to calibrate the sensitivity of the analytical instrument for each analyte in the samples to ensure the reliability of analytical results. To perform this calibration, reference materials (RMs) that serve as “yardstick” are - Realization of an efficient metrological traceability using the quantitative NMR method -Toshihide Ihara1* , Takeshi Saito1 and Naoki Sugimoto21. National Metrology Institute of Japan, AIST Tsukuba Central 3, Umezono1-1-1, Tsukuba 305-8563, Japan *E-mail : , 2. Division of Environmental Chemistry, National Institute of Health Sciences Kamiyoga 1-18-1, Setagaya-ku 158-8501, JapanReceived original manuscript October 6,2008, Revisions received December 26,2008, Accepted December 26,2008Reference materials are indispensable for accurate analysis of hazardous substances in food and the environment. For organic substances, however, the dissemination of reference materials is hopelessly unable to catch up with today’s rapidly proliferating analytical needs. To solve this problem, analytical techniques were improved to develop a method in which a single primary reference material could provide accurate quantitative measurements for a wide variety of organic compounds. In pursuit of this goal, we turned our attention to the 1H NMR method. We improved upon the method to allow precise comparisons of signal quantities from protons with different chemical shifts, enabling calibration at an acceptable level of uncertainty for a variety of organic reference materials using a primary reference material for protons. This result opens the prospect of highly efficient metrological traceability, reducing the required number of national reference materials to a minimal level.Expansion of organic reference materials for the analysis of hazardous substances in food and the environmentKeywords : Chemical metrology, metrological traceability, reference material, nuclear magnetic resonance spectroscopy, primary method of measurement[Translation from Synthesiology, Vol.2, No.1, p.12-22 (2009)]

※このページを正しく表示するにはFlashPlayer9以上が必要です