Determination of fluorine in tea using high-resolution molecular absorption spectrometry with electrothermal vaporization of the calcium mono-fluoride CaF.

摘要: Abstract High-resolution continuum source molecular absorption of the calcium mono-fluoride molecule CaF in a graphite furnace has been used to determine fluorine tea after acid digestion, alkaline solubilization and preparation conventional aqueous infusion. The strongest ‘line’ is at 606.440 nm, which part rotational fine structure X 2 Σ +  −  A Π electronic transition; it bond dissociation energy 529 kJ mol −1 , comparable with other molecules for determination. One advantage using Ca as molecule-forming reagent that spectral interferences are extremely unlikely range its absorption. Another acts both forming chemical modifier, so no be added, making method very simple. only disadvantage somewhat negative influence on tube lifetime. limit detection was found 0.16 mg L F, corresponding 1.6 ng F absolute, calibration curve linear between 0.5 25 mg L correlation coefficient R  = 0.9994. results obtained certified reference material were agreement value 95% confidence level. There also difference an digestion 10 samples, based paired t -test. values samples ranged 42 μg g 87 μg g F; infusions contained 21 μg g 56 μg g extraction rate 48% 74%.