Research & Translational Sciences, Swedish Orphan Biovitrum AB, Tomtebodavägen 23A, SE-112 76, Stockholm, Sweden.
Research & Translational Sciences, Swedish Orphan Biovitrum AB, Tomtebodavägen 23A, SE-112 76, Stockholm, Sweden.
Anal Biochem. 2020 Jun 1;598:113703. doi: 10.1016/j.ab.2020.113703. Epub 2020 Apr 1.
Simple and direct determination of sulfate ion concentrations has many important applications, such as analysis of sulfohydrolase activities in biological fluids. Unfortunately, a reported barium-rhodizonate spectrophotometric method with many advantages faces a solubility challenge. To overcome this problem, solvation of rhodizonate complexes in its metathesis reaction was systematically investigated by 46 solvents/compounds using curvilinear regression methods to fit sulfate calibration intervals for signal linearity and color stability. The results revealed solvent structure-activity relationships to the color formation and provided optimal solvent formulae that enable this colorimetry in the stoichiometric way. The limit of water content in the colorimetric matrix increased from 20 to 45% and color formed for reading was stable for 45-135 min. The rhodizonate reagents were stable at -70 °C for >6 months. This established the robustness of the assay, which can now measure the sulfate ion concentration at 0.18 nmol, in comparison to 1 nmol of the early reports. The method provides a simple and direct analysis of sulfate ion, suitable for kinetics studies of sulfohydrolase activity in biological fluids.
简单直接地测定硫酸根离子浓度在许多方面都有重要应用，例如分析生物体液中的磺基水解酶活性。遗憾的是，一种具有许多优点的钡-试卤灵分光光度法却面临溶解度的挑战。为了解决这个问题，我们系统地研究了 46 种溶剂/化合物在反离子交换反应中对试卤灵络合物的溶解作用，采用曲线回归方法拟合硫酸根校准区间，以获得信号线性和颜色稳定性。结果揭示了溶剂结构与颜色形成之间的关系，并提供了最佳溶剂配方，使得比色法能够以化学计量的方式进行。比色基质中含水量的限制从 20%增加到 45%，用于读数的颜色在 45-135 分钟内稳定。试卤灵试剂在-70°C 下稳定>6 个月。与早期报告的 1nmol 相比，该方法现在可以在 0.18nmol 处测量硫酸根离子浓度，从而证明了该测定方法的稳健性。该方法提供了一种简单直接的硫酸根离子分析方法，适用于生物体液中磺基水解酶活性的动力学研究。
