Causes of error in analytical chemistry: Results of a web-based survey of proficiency testing participants

摘要

Results of a voluntary-response survey of respondent-identified causes of unacceptable results in nine proficiency testing schemes are reported. The PT schemes were predominantly environment and food analysis schemes. 111 respondents reported 230 identified causes of error. Sample preparation (16 % of causes reported), Equipment failures (13 %), 'Human error' (13 %) and Calibration (10 %) were the top four general causes of poor analytical results. Among sample preparation errors, sample extraction or recovery problems were the most important causes reported. Most calibration errors were related to errors in calculation and dilution and not in availability or quality of calibration materials. No failures were attributed to failures in commercial software; software-related problems were largely associated with user input errors. Corrective actions were generally specific to the particular problem identified. Review of all reported causes indicated that about 44 % could be attributed to simple operator errors.