Determination of fluoride in Antarctic krill (Euphausia superba) using ion chromatography and its pretreatments selection

Abstract

A rapid, sensitive and reliable method to quantify fluoride in Antarctic krill has been established. Four different pretreatment methods were used for the extraction of fluoride: double-deionised water extraction, sulphuric acid distillation, hydrochloric acid extraction, and pH adjustment with buffer after hydrochloric acid extraction. Four methods of comparative analysis revealed that sulphuric acid distillation was suitable preparation for ion chromatography determination of fluoride in Antarctic krill (fluoride content 288.7 ± 10.2 mg/kg). The method was partially validated in linearity, accuracy, and precision. The linear range was from 0.1 to 10.0 mg/l with the regression coefficient of 0.99998. The accuracy expressed as the recoveries of standard addition ranged from 95.3% to 101.3%, the relative standard deviation (n = 8) was 1.8-1.9%. With this method, the 3σ limit of detection was 0.06 mg/l of fluoride in Antarctic krill. Our results indicate that the method (limit of quantification 0.2 mg/l) could be well applied for the determination of fluoride in Antarctic krill.