Reversed-phase high performance liquid chromatography (RP-HPLC) is the most widely used chromatographic method. In addition to hydrophobic interactions, additional interactions such as electrostatic interactions may participate in the retention behaviour of an analyte. This makes it possible to use RP-HPLC for many types of analyte. We describe a simple method for separating inorganic anions on a C18 column, in which retention of inorganic anions is almost entirely due to electrostatic interactions. This leads to rapid separations as well as higher theoretical plate numbers. We used 2 mM phosphoric acid containing a low concentration of disodium molybdate as the mobile phase, which allows UV detection of non-UV-absorbing anions. With this method, we determined eight inorganic anions including several non-UV-absorbing anions photometrically at 220 nm. The detection limits of the examined eight inorganic anions calculated at a signal-to-noise ratio of 3 were between 0.3 and 10 μM. The detector response was linear over three orders of magnitude of inorganic anion concentration. The proposed RP-HPLC/UV method was successfully applied to determine inorganic anions in some water samples.

中文翻译：

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使用磷钼酸盐流动相在反相 C18 柱上分离无机阴离子

反相高效液相色谱（RP-HPLC）是应用最广泛的色谱方法。除了疏水相互作用之外，其他相互作用（例如静电相互作用）也可能参与分析物的保留行为。这使得 RP-HPLC 可以用于多种类型的分析物。我们描述了一种在 C18 柱上分离无机阴离子的简单方法，其中无机阴离子的保留几乎完全是由于静电相互作用。这导致快速分离以及更高的理论塔板数。我们使用含有低浓度钼酸二钠的 2 mM 磷酸作为流动相，可以对非紫外吸收阴离子进行紫外检测。通过这种方法，我们在 220 nm 处通过光度法测定了 8 种无机阴离子，包括几种非紫外线吸收阴离子。以信噪比为3计算的8种无机阴离子的检测限在0.3至10μM之间。检测器响应在三个数量级的无机阴离子浓度范围内呈线性。所提出的 RP-HPLC/UV 方法已成功应用于测定一些水样中的无机阴离子。