MCX SPE Cartridges

Chemical Structure of MCX Sorbent: Sulfonic Acid Functionality Mixed-mode cation exchange (MCX) cartridges represent a sophisticated approach to solid-phase extraction, combining both hydrophobic and ionic retention mechanisms. The sorbent consists of a silica-based substrate with bonded hydrophobic chains (typically C8 or C18) and sulfonic acid groups. These sulfonic acid moieties are strong acid functionalities (pKa

Common Forensic Drugs Analyzed with MCX SPE Mixed-mode cation exchange (MCX) solid phase extraction has become a gold standard in forensic toxicology laboratories for analyzing basic drugs and their metabolites. The most commonly targeted compounds include amphetamine and methamphetamine (phenylethylamine derivatives) and cocaine metabolites such as benzoylecgonine and norcocaine. These substances are potent central nervous

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:

Properties of Basic Analytes Basic compounds represent a diverse class of analytes characterized by their ability to accept protons or donate electron pairs. These compounds typically contain nitrogen atoms with lone electron pairs, such as amines, alkaloids, pharmaceuticals, and various drug metabolites. The fundamental property governing their behavior in solid-phase extraction (SPE) is their pKa