Instrumental analysis of trace elements occupies center stage in the field of chemical analysis today. Consequently, the reliability of analytical values has become particularly crucial. Ensuring the accuracy of results is also very important for inter-laboratory comparisons. The use of reference materials is necessary in order to ensure the reliability of data. CERI is the only calibration laboratory designated by the Ministry of International Trade and Industry in accordance with the Traceability System based on the Measurement Law. In this capacity, it produces an array of primary reference materials-including standard gases, pH standard solutions, metal standard solutions, and anion standard solutions and prepares secondary reference materials.