Major Plasma Interferences: Phospholipids, Proteins, and Salts Plasma presents one of the most challenging matrices for analytical chemists due to its complex composition. The three primary interference categories that significantly impact LC-MS analysis are phospholipids, proteins, and salts. Phospholipids are particularly problematic as they cause matrix effects, ion suppression, shorten column lifetime, increase MS maintenance […]

Target Antidepressants for MCX SPE Extraction Mixed-mode cation exchange (MCX) solid phase extraction is particularly well-suited for the isolation of basic antidepressant compounds from biological matrices. The target antidepressants in this method include: Fluoxetine (Prozac®) – A bicyclic antidepressant with pKa of approximately 9.8, widely used for depression treatment with therapeutic levels of 40-450 ng/mL

Overview of Mixed-Mode Cation Exchange SPE Mechanisms Mixed-mode solid phase extraction represents a sophisticated approach to sample preparation that combines multiple retention mechanisms within a single sorbent. For basic drug analysis, mixed-mode cation exchange (MCX and WCX) cartridges provide superior selectivity and sensitivity compared to traditional reversed-phase materials. These sorbents operate through a dual mechanism: