Due to medical relevance and a direct correlation with some diseases, accurate quantification of oxalic acid in different complex matrices is required. Effective chromatographic separation of this strong carboxylic acid was achieved by ion exclusion chromatography (IELC). Sensitive and selective detection was carried out by means of electrospray ionization-tandem mass spectrometry. Furthermore, it was shown that the isobaric interference of lactic acid is chromatographically resolved. Structurally similar compounds like glyoxylic acid and glycolic acid were baseline separated as well. The application of stable isotope dilution analysis with ¹³C₂ oxalic acid facilitated precise quantification. The developed method was validated with a reference oxalate sample of human urine diluted to a range of 10–500 μM. Finally, the applicability of this method was demonstrated on complex matrices, like mouse urine and supernatants of primary mouse hepatocyte cell cultures.

由于医学上的相关性以及与某些疾病的直接相关性，因此需要精确定量不同复杂基质中的草酸。该强羧酸的有效色谱分离是通过离子排阻色谱法（IELC）实现的。灵敏和选择性的检测是通过电喷雾电离串联质谱法进行的。此外，显示出通过色谱法分离了乳酸的同量异位干扰。基线分离结构相似的化合物，如乙醛酸和乙醇酸。¹³ C ₂稳定同位素稀释法的应用草酸有助于精确定量。用稀释至10-500μM范围内的人尿草酸参考样品验证了该方法的有效性。最后，该方法的适用性在复杂的基质上得到了证明，例如小鼠尿液和原代小鼠肝细胞培养物的上清液。