Evaluation of a Solid-Phase Extraction Method for Codeine and Morphine in Urine Using Cerex Polycrom  Clin II Columns and the Speedisk  48 Pressure Processor at a High-Throughput Forensic Drug-Testing Laboratory

Extraction and determination of opium alkaloids in urine samples using dispersive liquid–liquid microextraction followed by high-performance liquid chromatography

“…Analytical procedures such as liquid-liquid extraction (LLE) [25], solid-phase extraction (SPE) [26][27][28] and ionic liquid-based aqueous two-phase system [1] have been developed for the determination of opium alkaloids. However, LLE usually requires some poisonous volatile organic solvents.…”

Ionic liquid-based aqueous two-phase system, a sample pretreatment procedure prior to high-performance liquid chromatography of opium alkaloids

“…Quantitative analysis of trace level of opium alkaloids is still a significant challenge demanding a rapid and effective sample preparation procedure prior to analysis. Currently, two principal methods have been used for sample pretreatment: liquid-liquid extraction (LLE) [4] and solid-phase extraction (SPE) [5][6][7]. However, LLE usually requires some poisonous volatile organic solvents.…”