IC Determination of Fluorine in Solid Biomass Fuel

Seven kinds of botanic substances were sampled as described in GB/T 28730-2012 and the optimized conditions for sample-pretreatment and IC analysis were found as follows:the sample (0.500 0 g) was fused with (1.0±0.1) g KOH in a nickel crucible at 250℃ and 550℃ for 30 min and 30 min in succession. The melt in the cooled crucible was taken up with 10 mL of water and then made up to 100 mL. Metrosep A16-150 column was used for IC-separation with mixed solution of 7.5 mmol·L^-1 Na₂CO₃ and 0.75 mmol·L^-1 NaOH as mobil phase. Restrain conductance detector was used in the determinations. Linearity range for fluorine was found between 0.02 and 1.0 mg·L^-1, with detection limit of 7.6 μg·L^-1. On the base of substantial samples, test for recovery was made by standard addition method, giving values of recovery in the range of 96.2% to 103% and values of RSD's (n=6) found were all less than 5.0%.