A highly sensitive fluorimetric method for the determination of fluoride in biological material with Al3+-calcein complex

A highly sensitive fluorimetric method for the determination of fluoride was established. The method was based on quenching of the fluorescence of the Al³⁺-calcein complex in CCl₃COOH-CH₃COOK buffer solution by fluoride. The fluorescence emission was measured at λ_ex/λ_em 480/503 nm, and the experimental variables and interference in this determination were studied. The linear calibration range was 0.8 ng/mL to 150 ng/mL and the detection limit was 0.2 ng/mL. The method was applied to determine fluoride in biological materials. The recovery was in the range of 96.3% to 104.7% and the relative standard deviation was 4.6%. The results obtained from the certified reference material by the present method agreed with the certified values.