Determination of phloroglucinol in human plasma by high-performance liquid chromatography–mass spectrometry

A sensitive and selective liquid chromatographic method coupled with mass spectrometry (LC–MS) was developed for the quantification of phloroglucinol in human plasma. Resorcinol was used as internal standard, with plasma samples extracted using ethyl acetate. A centrifuged upper layer was then evaporated and reconstituted with mobile phase. The reconstituted samples were injected into a C18 XTerra MS column (2.1×100 mm) with 3.5-μm particle size. The analytical column lasted for at least 500 injections. The mobile phase was 15% acetonitrile (pH 3.0), with flow-rate at 200 μl/min. The mass spectrometer was operated in negative ion mode with selective ion monitoring (SIM). Phloroglucinol was detected without severe interferences from plasma matrix when used negative ion mode. Phloroglucinol produced a parent molecule ([M–H]−) at m/z 125 in negative ion mode. Detection of phloroglucinol in human plasma was accurate and precise, with quantification limit at 5 ng/ml. This method has been successfully applied to a study of phloroglucinol in human specimens.