@article{oai:nitech.repo.nii.ac.jp:00003919,
 author = {Yuchi, Akio and Yanai, Naoki and Wada, Hiroko and Nakagawa, Genkichi},
 issue = {9},
 journal = {Analyst},
 month = {Jan},
 note = {Equilibria between aluminium fluoro complexes and Tiron (sodium 1,2-dihydroxybenzene-3,5-disulphonate; Na2H2L) were studied. Formation of the mixed ligand complexes of AILFj(j=1 or 2) defines the interference by aluminium in the determination of fluoride with ion-selective electrodes using Tiron as a masking reagent. Al Fj + H22- ? Al 2 + jF- + 2H + Al Fj + 2H2?2- ? Al 3 + jF- + 2H+  The second and even the third Tiron  can react with these mixed ligand complexes to liberate fluoride together with two to four protons. Hence higher recoveries of fluoride  are obtained at higher pH with  a higher concentration of Tiron. At pH 6, 0.1 mol dm-3 Tiron solution has a tolerance limit of around 10-3 mol dm -3 of aluminium, and is superior to the corresponding solution of citrate or CDTA in releasing fluoride from aluminium. Tiron was applied to the analysis of crude cryolite and fluorspar after decomposition of the samples with aluminium chloride solution., application/pdf},
 pages = {1405--1408},
 title = {Tiron as a masking reagent for aluminium in the determination of fluoride with an ion-selective electrode: Equilibrium studies and application},
 volume = {113},
 year = {1988}
}