The comparator instrumental neutron activation analysis (INAA) method was used for certification of arsenic in Korea Research
Institute of Standards and Science (KRISS) reference materials 108-04-001 (Oyster Tissue). The certified value was determined
by analyzing one sample of approximately 0.15 g from ten bottles selected by random sampling. Potentially significant sources
of uncertainty were taken into consideration using the guideline given by ISO. A complete evaluation of all sources of uncertainty
yielded an expanded uncertainty for the mean value of this reference material of 4.7% at approximately 95% level of confidence.