N-containing heterocycles (NCHs) are largely used as precursors for pharmaceuticals and can enter the environment. Some NCHs have been shown to be toxic, persistent, and very mobile in the environment. Thus, they have received increasing attention in the past years. However, the analysis of these polar compounds in environmental samples is still a challenge for liquid chromatography. This paper investigates the use of mixed-mode liquid chromatography (MMLC), which has reversed-phase and ion exchange characteristics for measurements of NCHs in water. NCHs with low pK_a (i.e., < 2.5) display mainly reversed-phase interactions (neutral species) with the stationary phase and those with higher pK_a (i.e., > 5) interact by a mixture of reversed-phase/ion exchange/HILIC mechanism. It was also shown that the presented method performs well in the quantification of the majority of the selected NCHs in surface water with MDLs between 3 and 6 μg/L, a low matrix effect and recoveries in the range of 77–96% except for pyridazine exhibiting 32% were achieved. The method was successfully employed to follow the degradation of NCHs in ozonation.

Ñ含杂环（NCHS）在很大程度上是作为药物前体，并且可以进入环境。已显示某些NCH在环境中有毒，持久且易移动。因此，它们在过去几年中受到越来越多的关注。然而，对环境样品中的这些极性化合物进行分析对于液相色谱法仍然是一个挑战。本文研究了混合模式液相色谱法（MMLC）的使用，该方法具有反相和离子交换特性，可用于测定水中的NCHs。p K _a低（即<2.5）的NCH主要表现出与固定相的反相相互作用（中性物质），p k _a较高的NCH（即，> 5）通过反相/离子交换/ HILIC机制的混合物相互作用。研究还表明，所提出的方法在定量分析地表水中大多数NCH的MDL在3至6μg/ L之间时表现良好，基质效应低，除哒嗪外的回收率在77–96％范围内达到32％。该方法已成功用于跟踪臭氧化中NCH的降解。