Simultaneous supercritical fluid extraction and chemical derivatization for the gas chromatographic–isotope dilution mass spectrometric determination of amphetamine and methamphetamine in urine

Supercritical fluid extraction in situ derivatization for simultaneous determination of chloramphenicol, florfenicol and thiamphenicol in shrimp

“…Unlike other reports on SFE in situ derivatization (López et al, 2004;Wang et al, 2001;David et al, 2000), derivatization reagent was pipetted directly into the collection solvent tube instead of the extraction chamber. This avoids side reactions between the matrix and the silylation reagent.…”

“…Li and his coworkers studied the solubility of the three pure amphenicols in SFE-CO 2 (Li, Maxwell, & Shadwell, 2002), but they did not explore the feasibility of recovering amphenicols in real samples. To shorten pretreatment time, several studies reported on in situ derivatization during SFE (López, Blanch, & Herraiz, 2004;Wang, Giang, & Ling, 2001;David, Campbell, & Li, 2000), in which derivatization reagent was introduced directly into the extraction chamber. This allowed the derivatization reaction to occur under the specific condition of supercritical temperature and pressure.…”

Simulation and optimization of silicon thermal CVD through CFD integrating Taguchi method

“…The computer simulation with Taguchi's route has been proposed to solve the problems of integrated manufacturing system [23]. Furthermore, by using Taguchi method, Wang et al [24] Greek symbols Ω 1 angular velocity of showerhead (rad/s) conditions of simultaneous supercritical fluid extraction and chemical derivation for the gas chromatographic-mass spectrometric determination of amphetamine and methamphetamine in an aqueous matrix. In addition, Taguchi method was employed to analyze influences of the moisture absorption on plastic ball grid array (PBGA) of package's warp during IR re-flow process [25].…”

Artifacts in the GC–MS profiling of underivatized methamphetamine hydrochloride

“…However, compared to confirmatory GC-MS protocols which require some sort of chemical derivatization [24][25][26][27][28], rapid GC-MS profiling usually involves no chemical derivatization. At some forensic laboratories that have large routine sample volumes it is still common practice to dissolve MAÁHCl exhibits or crystals in a polar organic solvent such as methanol and inject directly an aliquot of the solution into a GC-MS without even alkalizing in advance the analyte from salt form into free-base form.…”