Vishnikin Andriy B, Khlyntseva Svitlana V, Bazel Yaroslav, Balogh Ioseph, Barchiy Ihor E
Department of Analytical Chemistry, P.J. Šafárik University in Košice, 04154 Košice, Slovakia.
Department of Analytical Chemistry, Dnipro National University, 49050 Dnipro, Ukraine.
Molecules. 2025 Apr 22;30(9):1872. doi: 10.3390/molecules30091872.
The elimination of absorbance of excess dye by selective oxidation was first proposed for analytical methods using the formation of ion-association complexes (IAs). On this basis, a new sensitive and selective spectrophotometric method for the determination of phosphate in the form of the IA of 11-molybdovanadophosphate with diindodicarbocyanine (DIDC) was developed. Symmetric diindodicarbocyanine and diindotricarbocyanine dyes can be completely oxidized by sufficiently strong oxidizing agents such as permanganate, dichromate, cerium (IV), and vanadate. Of the three dyes investigated (DIDC, N,N'-dipropyldiindodicarbocyanine, and diindotricarbocyanine), the best results were obtained with DIDC. A mixture of molybdate, vanadate, and nitric acid was preferably used as an oxidizing agent. Selective decolorization of only free dye ions, as well as changes in the IA spectrum compared to the dye spectrum, were explained by the isolation of the dye due to the formation of poorly soluble IA nanoparticles and changes in the redox potential of the dye due to its aggregation. The following optimal conditions for phosphate determination were found: 0.3 M nitric acid, 0.43 mM sodium molybdate, 0.041 mM sodium vanadate, 0.015 mM DIDC, and 18 min for the reaction time. The molar absorptivity of the IA was 1.86 × 10 mol·L·cm at 600 nm, and the detection limit for phosphate was 0.013 µM. The developed method was applied to the determination of phosphate in natural water samples.
通过选择性氧化消除过量染料的吸光度，这一方法最初是针对使用离子缔合配合物（IA）形成的分析方法提出的。在此基础上，开发了一种新的灵敏且选择性的分光光度法，用于测定11 - 钼钒磷酸与二吲哚二碳菁（DIDC）形成的IA形式的磷酸盐。对称的二吲哚二碳菁和二吲哚三碳菁染料可被足够强的氧化剂如高锰酸盐、重铬酸盐、铈（IV）和钒酸盐完全氧化。在所研究的三种染料（DIDC、N，N'-二丙基二吲哚二碳菁和二吲哚三碳菁）中，使用DIDC获得了最佳结果。优选使用钼酸盐、钒酸盐和硝酸的混合物作为氧化剂。仅游离染料离子的选择性脱色以及与染料光谱相比IA光谱的变化，是由于形成难溶性IA纳米颗粒导致染料的分离以及由于其聚集导致染料氧化还原电位的变化来解释的。发现了以下测定磷酸盐的最佳条件：0.3 M硝酸、0.43 mM钼酸钠、0.041 mM钒酸钠、0.015 mM DIDC，反应时间为18分钟。该IA在600 nm处的摩尔吸光系数为1.86×10 mol·L·cm，磷酸盐的检测限为0.013 µM。所开发的方法应用于天然水样中磷酸盐的测定。
