Stability Monitoring of Pesticide Residues in a Chinese Cabbage Certified Reference Material

摘要

Certified reference materials (CRMs) with values traceable to the International System of Units (SI) play a key role for harmonization of measurement results among laboratories. CRMs can be used for validation/verification of analytical methods employed in individual laboratories and for quality assurance or testing proficiency of laboratories. Therefore, national metrology institutes (NMIs) of developed countries have been producing CRMs of various types, which are similar to samples to be analyzed, in respect to matrix types, analytes, and their concentrations. Our laboratory, as the NMI of Korea, also has been developing CRMs for environmental, food, clinical, and material analysis. Unfortunately, (potential) users often face a problem that CRMs matching to their samples are not available. In the organic analysis field, the problem is, in most of case, due to instability of target analytes in CRMs as many organic compounds of interest are air-sensitive, light-sensitive, degrading thermally or in acidic or akalic environment, and/or evaporating out of matrix during long-term storage. Therefore, ensuring stability is a key factor for successful production of CRMs for organic analysis.