For quantification of toxic chemical substances in food and environment matrices, it is essential to calibrate of analytical instruments. We are developing and improving analytical techniques to assay purities and concentrations traceable to the SI such as freezing point depression method, titrimetry and quantitative nuclear magnetic resonance (qNMR) spectroscopy for accurate characterization of organic reference materials (high-purity materials and standard solutions). Using these developed techniques, we contribute to supply of reliable organic reference materials for calibration of analytical instruments by developments of certified reference materials (CRMs) and by providing calibration services.