摘要
本文研究了乙基罗丹明B-磷钼杂多酸-聚乙烯醇(PVA)显色体系,提出了高灵敏度的测磷分光光度法。缔合物最大吸收λ_(max)=584nm。表观摩尔吸光系数ε_(586)为3.2×10~5L·mol^(-1)·cm^(-1)。提高介质酸度和添加还原剂可消除SiO_3^(2-)、AsO_4^(3-)等的干扰。缔合物中P(V):ERB^+=1:4。红外光谱研究证明,染料阳离子与杂多酸阴离子形成了离子对缔合物。本法可用于钢样及试剂中磷的测定,测定下限达1×10^(-5)％(1g试样)。
A new sensitive colour system of Ethyl Rhodamin B-molybdophosphoric acid-PVAhas been studied. The optimum conditions for pbosphorus determination are [HNO_3]=0.56mol/dm^3,[MoO_4^(2-)]=2.4×10^(-2)mol/dm^3, [ERB^+]=8.0×10^(-5)smol/dm^3 and 0.12% PVA. Theion-associate exhibits maximum absorptivity at 584nm. At the working wavelength of 586nm its apparent molar absorptivity was found to be 3.2×10~5 L.mol^(-1).cm^(-1).Beer′s law isobeyed in the range of 0 to 1.5μg of P(V) per 25mL. The colour of the aqueous solutionwas stable for at least lh. The molar ratio of P(V) to FRB^+ in ion-associate was estab-lished to be 1:4. Infrared spectra studies show that an ionic bond occurs between ERBand phosphomolybdate and that the structure of the dye molccule is not of effected by the for-mation of the ion-assosiate.The effect of inteifering ions, such as As(Ⅴ), Si(Ⅳ) can bedecreased by increasing the acidity and addir?g mixed reductants. Phosphorus in steel andsome chemical reagents were determined directly at 1×10^(-5)% level by the proposed methodwith satisfactory results.
出处
《应用化学》
CAS
CSCD
北大核心
1989年第5期39-43,共5页
Chinese Journal of Applied Chemistry
基金
国家自然科学基金
关键词
乙基罗丹明B
磷钼杂多酸
分光光度法
Ethyl Rhodamine B
Heteropolymolybdophosphoric acid
Specetrophotometry
