n-methyl-n-(tert-butyldimethylsilyl)trifluoroacetamide and acetonitrile

A sample preparation method for the determination of hydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) in sediment samples was developed using gas chromatography-mass spectrometry (GC-MS). Dispersive liquid-liquid microextraction (DLLME) with derivatization was performed following the subcritical water extraction (SWE) that provided which was provided by accelerated solvent extraction (ASE). Several important parameters that affected both SWE extraction and DLLME, such as the selection of organic modifier, its volume, extraction temperature, extraction pressure and extraction time were also investigated. High sensitivity of the hydroxylated PAHs derivatives by N-(tert-butyldimethylsilyl)-N-methyl-trifluoroacetamide (MTBSTFA) could be achieved with the limits of detection (LODs) ranging from 0.0139 (2-OH-nap) to 0.2334 μg kg(-1) (3-OH-fluo) and the relative standard deviations (RSDs) between 2.81% (2-OH-phe) and 11.07% (1-OH-pyr). Moreover, the proposed method was compared with SWE coupled with solid phase extraction (SPE), and the results showed that ASE-DLLME was more promising with recoveries ranging from 57.63% to 91.07%. The proposed method was then applied to determine the hydroxylated metabolites of phenanthrene in contaminated sediments produced during the degradation by two PAH-degraders isolated from mangrove sediments.

Topics: Acetamides; Acetonitriles; Fluoroacetates; Gas Chromatography-Mass Spectrometry; Geologic Sediments; Hydrogen-Ion Concentration; Liquid Phase Microextraction; Organosilicon Compounds; Polycyclic Aromatic Hydrocarbons; Pressure; Solid Phase Extraction; Temperature; Time Factors; Water; Water Pollutants, Chemical

Ibogaine, an indolamine derivative, is currently being investigated as a potential agent in the treatment of stimulant and opiate addiction. We developed a rapid, sensitive, and specific method for the analysis of ibogaine and its putative active metabolite, 12-hydroxy-ibogamine (12-OH-ibogamine). This assay employs a one-step basic extraction with n-butyl chloride-acetonitrile (4:1), followed by derivatization of the metabolite using N-methyl-N-(tert-butyldimethylsilyl)-trifluoroacetamide. The derivatized extracts were analyzed by capillary gas chromatography-positive ion chemical ionization-mass spectrometry. The ions monitored were at m/z 311, 314, and 411, which correspond to the protonated molecules (MH+) for ibogaine, ibogaine-d3, and 12-OH-ibogamine.tert-butyldimethylsilyl, respectively. Linear standard curves were obtained over the concentration range of 1 0-1 000 ng/mL (average r2, 0.995 for ibogaine and 0.992 for 12-OH-ibogamine; n = 3). Limits of quantitation were 10 ng/mL. The interrun and intrarun coefficients of variation for the assay of ibogaine at 25, 100, and 300 ng/mL ranged from 2.9 to 8.8%. We also established the extraction and chromatographic conditions to monitor the 12-hydroxylated metabolite. A suitable internal standard was not yet obtained so the method could only provide semiquantitative information for 12-OH-ibogamine. Chemical stability studies of these analytes indicated that ibogaine and 12-OH-ibogamine were stable in a human plasma matrix at room temperature for a period of at least 1 week.

Topics: Acetamides; Acetonitriles; Butanes; Calibration; Fluoroacetates; Gas Chromatography-Mass Spectrometry; Hallucinogens; Humans; Hydroxylation; Ibogaine; Organosilicon Compounds; Quality Control; Reference Standards; Temperature; Trifluoroacetic Acid