Effects of triglycerides levels in human whole blood on the extraction of 19 commonly used drugs using liquid-liquid extraction and gas chromatography-mass spectrometry

Quantitative Determination of Methohexital in Human Whole Blood by Liquid Chromatography Tandem Mass Spectrometry

A rapid, simple and sensitive liquid chromatography tandem mass spectrometry method for the determination of methohexital in human whole blood was developed and validated. Ethyl acetate/n-hexane (9:1) was used as extraction solvent while aprobarbital was used as internal standard. Methohexital was recovered by liquid-liquid extraction from 100 μL of human whole blood. The mobile phase was water-acetonitrile, and an ACQUITY BEH C18 (2.1 × 100 mm, 1.7 μm) column was adopted. Negative electrospray ionization source and multiply reaction monitoring mode were applied. The transitions of m/z were 261.2/42.2 and 261.2/119.0 for methohexital. The limit of detection was 0.5 ng/mL, which was lower than the previous methods. Wide linear range (2-2,000 ng/mL) with a good correlation coefficient (r > 0.99) was also obtained. The intra- and inter- day precisions represented by relative standard deviation were <11.5%, and the recoveries were >79.67%. This analytical method involved small sample volume and had been proven to be rapid, easy, sensitive and specific. Therefore, it could be used for the clinical analysis of methohexital.

Capacitive sensing of triglyceride film reactions: a proof-of-concept demonstration for sensing in simulated duodenal contents with gastrointestinal targeting capsule system

Ingestible capsule systems continue to evolve to overcome drawbacks associated with traditional gastrointestinal (GI) diagnostic and therapeutic processes, such as limitations on which sections of the GI tract can be accessed or the inability to measure local biomarker concentrations. We report an integrated capsule sensing system, utilizing a hybrid packaging scheme coupled with triglyceride film-coated capacitive sensors, for measuring biochemical species present in the duodenum, such as pancreatic lipase and bile acids. The system uses microfabricated capacitive sensors interfaced with a Bluetooth low-energy (BLE)-microcontroller, allowing wireless connectivity to a mobile app. The triglyceride films insulate the sensor surface and react either with 0.01-1 mM lipase via hydrolysis or 0.07-7% w/v bile acids via emulsification in simulated fluids, leading to measurable changes in capacitance. Cross reactivity of the triglyceride films is evaluated in both phosphate buffered saline (PBS) as well as pancreatic trypsin solutions. The film morphology is observed after exposure to each stimulus to better understand how these changes alter the sensor capacitance. The capsule utilizes a 3D-printed package coated with polymers that remain intact in acid solution (mimicking gastric conditions), then dissolve at a duodenum-mimicking neutral pH for triggered opening of the sensing chamber from which we can subsequently detect the presence of pancreatic lipase. This device strategy represents a significant step towards using embedded packaging and triglyceride-based materials to target specific regions of the GI tract and sensing biochemical contents for evaluating gastrointestinal health.

Determination of carbazole and halogenated carbazoles in human serum samples using GC-MS/MS

Carbazole and halogenated carbazoles have been widely detected throughout the environment in soil, river deposits, and lake sediments. Human exposure to these compounds may occur through inhalation, drinking water, dietary intake and/or skin contact, and exposure levels in the body may be evaluated by measuring them in serum or blood. This paper reports the method development and validation for the analysis of carbazole and 11 halogenated carbazoles in human blood and/or serum samples. A small sample size of 100 μL of blood or serum was employed for the analysis. The samples were prepared through salting-out liquid-liquid extraction (LLE) by using hexane/ethyl acetate (4:1, v/v) as the extraction solvent and aqueous MgSO₄ (37.5 wt%) as the salting-out regent, respectively. Sample analysis was performed using gas-chromatography (GC) coupled with a tandem mass spectrometer (MS/MS) in an electron impact (EI) mode. The developed method demonstrated low detection limits in the range of 0.02-0.27 ng/mL, intra-day accuracy ranging from 81.2% to 125%, and inter-day accuracy from 91.0% to 117%. The intra- and inter-day precisions, calculated by relative standard deviations (RSDs), were in the ranges of 1.0-16.0% and 1.8-16.4%, respectively. The developed method was applied to the analysis of 50 human serum samples collected from pregnant women in Southern California in 2012. Low concentrations of carbazole were measured in 18 samples, while halogenated carbazoles were not detected in any of the samples.