Abstract:
Multi-period environmental geochemical mapping for obtaining a continuous record of environmental change requires the reduction of between-period analytical bias(variable bias). Criteria are developed to run the proficiency test for analytical laboratories involved in such kind of work. These include (1) the rate of unqualification of △logC, (2) the similarity coefficient calculated as the correlation coefficient between element values of a group of standard reference samples and values of these samples determined by different laboratories, and (3) the similarity of maps composed of element values of many standard reference samples in virtualized spatial distribution with maps composed of element values determined by different labs.