Homogeneity and stability testing of a candidate reference material for the determination of total arsenic in tuna fish sample

Abstract

Total arsenic in tuna fish is usually found in relatively very low concentrations of below 10 μg/g. Two major difficulties in the measurement of total arsenic in tuna fish are the concentration and its matrix interferences. Accuracy and precision in its measurement is mandatory for an accreditated testing laboratory, therefore the availability of a suitable Reference Material (RM) is necessary. RM is a material or substance with one or more of its properties being sufficiently homogeneous and stable that are well established to be used for calibration of an apparatus, the assessment of a measurement method, or for assigning values to materials (ISO Guide 30-Ref C1). RMs are necessary in method development and validation, estimation of measurement uncertainty, internal quality control, proficiency testing and training. Both homogeneity and stability are essensial in the preparation of a RM of biological origin. The National Research Council Canada (NRC) developed Certified Reference Material (CRM) DORM-2, dogfish muscle CRM for trace metals, which was recently replaced by DORM-3. However, in Indonesia CRMs are difficult to purchase. The objective of this study is to provide a RM which can be used as an in-house referencebottle number was applied in this analysis. Statistical analysis was carried out and the uncertainty of homogeneity for total arsenic was calculated using the one-way analysis of variance (ANOVA).