Development and validation of a qualitative GC-MS method for THCCOOH in urine using injection-port derivatization

设计制作了一套用于气相色谱-质谱(GC-MS)分析极性有机物的在线衍生装置,并将其应用于大气颗粒物样品中极性有机物的检测。将大气颗粒物滤膜样品置于GC-MS进样口,通过使用套针组件,匀速引入气态衍生试剂N-甲基-N-(三甲基硅烷)三氟乙酰胺(MSTFA),使其在衬管内于310 ℃下与待测物接触,10 min即可完成硅烷化在线反应。反应过程中,色谱柱箱保持低温,衍生产物得以在柱头保留,反应完成后色谱柱箱程序升温,使衍生产物直接进行后续分离检测。应用在线衍生装置建立有机酸分析方法,获得了一元酸、二元酸、芳香酸、醇等极性有机物的检测信息,涵盖了大气化学分析常见的大部分目标化合物。该方法检出限为0.02~0.53 mg/L,线性相关系数为0.976~0.996,日内、日间RSD为0.27%~7.28%,适用于批量大气环境样品检测。与传统离线衍生技术相比,本装置使衍生反应处于高温惰性气体氛围,排除空气中水分对衍生试剂的损耗和衍生产物降解风险,反应稳定、效率高;固体滤膜上有机物进行热解吸的同时完成在线衍生,样品需求量小,操作简单,零有机试剂污染,并有望应用于醇类、酚类等多种极性有机化合物的分析。此外, 该装置搭建简单,可模块化设计,适用于不同品牌气相色谱仪,具有商业化推广前景。

Developments in injection port derivatization

Injection port derivatization following ion-pair hollow fiber-protected liquid-phase microextraction (LPME) for the trace determination of acidic herbicides (2,4-dichlorobenzoic acid, 2,4-dichlorophenoxyacetic acid, 2-(2,4-dichlorophenoxy)propionic acid, 3,5-dichlorobenzoic acid, 2-(2,4,5-trichlorophenoxy)propionic acid) in aqueous samples by gas chromatography/mass spectrometry (GC/MS) was developed. Prior to GC injection port derivatization, acidic herbicides were converted into their ion-pair complexes with tetrabutylammonium chloride in aqueous samples and then extracted by 1-octanol impregnated in the hollow fiber. Upon injection, ion pairs of acidic herbicides were quantitatively derivatized to their butyl esters in the GC injection port. Thus, several parameters related to the derivatization process (i.e., injection temperature, purge-off time) were evaluated, and main parameters affecting the hollow fiber-protected LPME procedure such as extraction organic solvent, ion-pair reagent type, pH of aqueous medium, concentration of ion-pair reagent, sodium chloride concentration added to the aqueous medium, stirring speed, and extraction time profile, optimized. At the selected extraction and derivatization conditions, no matrix effects were observed. This method proved good repeatability (RSDs <12.3%, n = 6) and good linearity (r2 > or = 0.9939) for spiked deionized water samples for five analytes. The limits of detection were in the range of 0.51-13.7 ng x L(-1) (S/N =3) under GC/MS selected ion monitoring mode. The results demonstrated that injection port derivatization following ion-pair hollow fiber-protected LPME was a simple, rapid, and accurate method for the determination of trace acidic herbicides from aqueous samples. In addition, this method proved to be environmentally friendly since it completely avoided open derivatization with potentially hazardous reagents.

Use of injection-port derivatization for the analysis of cocaine and its metabolites in urine by gas chromatography–tandem mass spectrometry

Injection port derivatization following sonication-assisted ion-pair liquid–liquid extraction of nonsteroidal anti-inflammatory drugs

The stability of 11-Nor-9-delta-tetrahydrocannabinol-9-carboxylic acid (THCCOOH) from urine specimens stored in polypropylene (PP), polyethylene (PE) and polystyrene (PS) containers was examined. Urinesamples containing 100μg/m L TI-ICCOOH were stored at -20°C, 4°C and 25°C up to 180 days. The samples were analyzed at 0,5, 10, 20, 30, 60, 90, 105, 135, 150 and 180 days, and alteration of the analyte pattern during storage were determined by a validated liquid chromatography-tandem mass (LC-MS/MS). The concentration of THCCOOH significantly decreased to approximately 20% of its initial concentration within 5 days in all three containers at all temperature conditions. All loses of THCCOOH were relatively stabilized after 5 days. The results indicated that THCCOOH was preferred to store in PP and PE containers at 4 °C.

Sample preparation procedure using extraction and derivatization of carboxylic acids from aqueous samples by means of deep eutectic solvents for gas chromatographic-mass spectrometric analysis

Determination of perfluorocarboxylic acids in water by ion-pair dispersive liquid–liquid microextraction and gas chromatography–tandem mass spectrometry with injection port derivatization

A simple, specific, and sufficiently sensitive liquid chromatography-tandem mass spectrometry (negative-ion electrospray ionization) methodology to determine mevalonic acid (MVA) in human plasma is described, and its application to the analysis of rat plasma MVA levels after rosuvastatin administration is demonstrated. The method was validated over the linearity range of 0.5-50.0 ng/ml (r(2) > 0.99) using deuterated MVA as an internal standard. The lower limit of quantification was 0.5 ng/ml. The assay procedure involved the isolation of MVA from plasma samples using solid-phase extraction. Chromatographic separation was achieved on a HyPurity Advance column with a mobile phase consisting of ammonium formate buffer (10 mM, pH 8.0) and acetonitrile (70:30, v/v). Excellent precision and accuracy were observed. MVA and deuterated mevalonolactone were stable in water and plasma under different storage and processing conditions. The recovery observed was low, which was attributable to a significant matrix effect. A significant decrease (30-40%; P < 0.05) was observed in rat plasma MVA levels after rosuvastatin administration.

Analysis of linear alkylbenzenesulfonates in water samples by large-volume injection-port derivatization and gas chromatography–mass spectrometry

Analysis of fluoxetine and norfluoxetine in human plasma by liquid-phase microextraction and injection port derivatization GC–MS

Development of a quick preparation method for the analysis of 11-nor-9-carboxy-∆9-tetrahydrocannabinol in human urine by phenylboronic-acid solid-phase extraction

Quantitative analysis of 11-nor-9-carboxy-tetrahydrocannbinol (THC–COOH) in urine by LC–MS/MS following a simple filtration

Topical application of THC containing products is not able to cause positive cannabinoid finding in blood or urine

Application of dynamic liquid-phase microextraction and injection port derivatization combined with gas chromatography–mass spectrometry to the determination of acidic pharmaceutically active compounds in water samples