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金(I)-碘化物-亚甲蓝(MB)体系适于金的浮选和分光光度测定。在最佳条件下,形成[(MB~+)(AuI_2~-)]·3C[(MB~+)(I_3~-)],它可与环巳烷一起上浮。将产物溶于甲醇并测定吸光度。在655纳米处,摩尔吸收率为3.4×10~5升·摩~(-1)厘米~(-1)。本方法是若丹明-B法灵敏性的三倍以上。Pt, pd, Ag和Hg会严重干扰,而Ir,Rh,Bi和Ca干扰程度比较小。建议用碲作扑收剂初步沉淀分离金。本法已用于测定铜试样中的微量金(约1×10~(-4)％)。我们已把由某些铂族金属的阴离子络合物与适当的碱性染料形成的微溶离子缔合化合物用来研究很灵敏的浮选-分光光度法,以便测定全部的六种铂族金属。摩尔吸收率(ε)在1.7-4.0×10~6升·摩~(-1)厘米~(-1)范围内。这是因为一个原子的金属与2-5个染料分子缔合。当将水相与极性小的适宜的溶剂一起摇动时,这种微溶化合物就聚集在相介面或分液漏斗的壁上。将洗涤过的沉淀物溶于极性溶剂中并测定该溶液的吸光度。在此类浮选中,用振摇的办法而分散在水相中的低极性的溶剂微粒起到类似于惰气气泡的作用而使沉淀物浮起。与碱性染料一起形成的离子缔合化合物是疏水的,这就使得它对于加到体系中去的表面活性剂无作用。本文论述了把该技术推广于分光光度测定金。至今所报道的大多数测定金的灵敏分光光度法是基于与单价碱性染料限离子一起的AuCl~-或AuBr_4~-离子对萃取,即最为人所知的若丹明B法(ε=9.4×10~4),用thio-Michler′s酮测定略为更灵敏(ε=1.2×10~5)。
The gold (I) -iodide-methylene blue (MB) system is suitable for gold flotation and spectrophotometry. Under the optimum conditions, [(MB ~ +) (AuI_2 ~)] · 3C [(MB ~ +) (I_3 ~ -)] is formed, which can float with the cyclohexane. The product is dissolved in methanol and the absorbance measured. At 655 nm, the molar absorptivity is 3.4 × 10 ~ 5 L · cm ~ (-1) cm ~ (-1). This method is more than three times more sensitive to Rhodamine-B. Pt, pd, Ag and Hg interfere severely, while Ir, Rh, Bi and Ca interfere less. It is recommended to use tellurium as a deflaking agent for preliminary precipitation of gold. This method has been used to determine the trace copper in the copper sample (about 1 × 10 -4%). We have used the sparingly soluble associative compounds formed from certain platinum group metal anionic complexes with suitable basic dyes to study very sensitive flotation spectrophotometry in order to determine that all six platinum group metals . The molar absorptivity (ε) is in the range of 1.7-4.0 × 10-6 liters · mol -1 (-1) cm -1. This is because one atom of metal is associated with 2-5 dye molecules. When the aqueous phase is shaken with a less polar, suitable solvent, the slightly soluble compound collects on the wall of the phase interface or separatory funnel. The washed precipitate is dissolved in a polar solvent and the absorbance of the solution is determined. In such flotation, the low-polarity solvent particles dispersed by shaking in a water phase act like gas bubbles to float the precipitate. The ion-associating compound formed with the basic dye is hydrophobic, which renders it ineffective with the surfactant added to the system. This article discusses the promotion of this technology to spectrophotometric gold. Most of the sensitive gold spectrophotometry methods reported so far are based on AuCl ~ - or AuBr_4 ~ - ion pair extraction with the monovalent basic dye limited ion, the best known rhodamine B method (ε = 9.4 × 10 ~ 4) was slightly more sensitive (ε = 1.2 × 10 ~ 5) as measured by thio-Michler’s ketone.