Pheochromocytoma is a rare disease with an annual diagnosis rate of 1-2 cases per 100000 people. About 30% of them are genetic patients, with clinical manifestations such as paroxysmal hypertension, headache, palpitations, hyperglycemia, etc., which may be accompanied by fatal cardiovascular complications. Pheochromocytoma can cause an increase in the secretion of catecholamines, so measuring catecholamines, norepinephrine, and their metabolites in plasma is of great value for clinical diagnosis. Usually, the determination of catecholamines in plasma includes dopamine (DA), norepinephrine (NE), epinephrine (E), as well as their metabolites 3-methoxytyramine (3-MT), norepinephrine (NMN), and norepinephrine (MN). The chemical information is shown in the table below. They are all alkaline and strongly polar compounds, usually extracted and purified using SPE materials based on ion exchange principles.

As shown in the figure below, WCX adsorbent binds carboxylate groups, ionizes and carries negative charges under neutral or slightly alkaline pH conditions in the solvent system, and adsorbs the positive ion | M+of the target compound through charge attraction to achieve capture effect. When the pH value of the solvent is adjusted to below 3, the carboxylate ions become saturated and electrically neutral, and the [M]+ions attracted by the loss of charge are eluted into the solvent, thereby achieving separation and purification from impurities.

Results and Discussion
Based on the above data, it can be seen that using WCX magnetic solid-phase extraction agent combined with AUTO M32 fully automatic extractor, catecholamine class standards in plasma can be extracted and purified. Through LC-MS/MS analysis and testing, the linearity is good, the results are accurate and precise, and meet the methodological requirements of basic quantitative testing. At the same time, the magnetic solid-phase extraction technology (mSPE) combined with the fully automated extraction system AUJTO M32 significantly reduces the traditional SPE's pipetting operation and real-time human monitoring, saving labor costs and significantly reducing the impact of human factors in pre-processing.