Highly Sensitive Determination for Catecholamines Using Boronate Affinity Polymer Monolith Microextraction with In-Situ Derivatization and HPLC Fluorescence Detection

Catecholamines such as dopamine, norepinephrine and epinephrine are important neurotransmitters containing cis-diol moieties, and HPLC with fluorescence detection (HPLC-FD) has been successfully used as highly sensitive detection method for them. However, the complex matrix of biological samples is always a challenge. Boronate affinity microextraction is practical to purify and enrich cis-diol compounds. In this study, we used in-situ derivatization in boronate affinity polymer monolith microextraction (BA/PMME) to combine sample pretreatment and derivatization, then followed by HPLC-FD to develop a highly sensitive and selective determination method for catecholamines. Taking poly(3-acrylamidophenyl boronic acid-co-ethylene dimethacrylate) as BA/PMME material and TMBB-Su as labeling reagent, catecholamines could be derivatizated in polymer monolith in-situ together with the sample enrichment and purification. Comparing with commonly used solid phase extraction followed by derivatization, fewer operation steps are required and higher sensitivity was obtained with LODs as low as 0.06-0.2 nM.