Assessment of technical problems in the analysis of inorganic elements in squid through proficiency testing

⋅A proficiency test of As, Cd, Fe, Mn and Zn in a dried squid powder.⋅The validity of the Assigned values was confirmed by interlaboratory comparison.⋅The En-numbers and z-scores were calculated to assess the reported results.⋅The possible reasons for questionable or unsatisfactory results were summarized.