Quantitative inorganic analysis of element forming volatile halide - by extn. from sample with reagent forming this halide, for high sensitivity and accuracy

摘要

Quantitative analysis of an inorganic chemical compsn. (I) is carried out by extn. of the element (II) to be determined from the sample in the gas phase and quantitative determn. of (II) in the gas phase. Extn. involves treating (I) with a reagent (III) forming a volatile halide with (II). For (I) contg. any of the above elements except F and Cl, the sample is treated as follows; (A) Dissolved in a molten metal bath and a (III) layer i.e. of nonvolatile metal halide, formed on the surface, (III) being Ni, Co, Cu or La fluoride or NaCl, whilst the melt consists of Ni, Cu or Pt and is melted in a crucible of material contg. F, per fluoro-phlogophite, which has been pretreated in a vacuum of 10 exp. -3 to 10 exp. -4 torr at a temp. 100-150 deg.C below the m.pt. of the crucible material. (B) Dissolved in a (III) melt, which is a complex alkali metal fluoride, pref. fluoroniobate, fluorotitanate and/or fluorotantalate, which can also contain 4-90% alkali metal chloride(s). (C) Mixed in crushed form with powdered (III), which is a nonvolatile metal halide, esp. Ni or Co fluoride or NaCl, and heated to 500-800 deg.C in a vacuum of 1 x 10 exp. -6 to 5 x 10 exp. -6 torr. If (I) contains F and/or Cl, the sample is dissolved in a metal melt contg. Si, pref. a melt of 9-15% Si, rest Cu, 4-12% Si, rest Au or 25-40% Si, rest Ni. A wide range of (II) specifically Al, As, B, C, Cr, Ge, Ga, Ir, Mo, Nb, Os, P, Pd, Re, Ru, Pb, Sb, Si, Sn, Ta, Te, Ti, U, V, W, Hg, Mn, F and Cl, can be determined with high sensitivity (detection limit 10 exp. -5 to 10 exp. -7%) and high accuracy (15-30% at concns. of 10 exp. -5 to 10 exp. -6%).