Determination of difenidol hydrochloride by capillary electrophoresis with electrochemiluminescence detection

Investigation of biodistribution by liquid-phase microextraction: Using a fatal diphenidol poisoning case

Liquid-phase microextraction (LPME) possesses a high potential to isolate organic substances from different sample matrices. In this work, LPME was applied for the first time to investigate the biodistribution of diphenidol in different biofluids, organs, and brain regions using a fatal poisoning case. Since the LPME of diphenidol hasn't been reported, the effect of supported liquid membrane (SLM), acceptor and donor phases, and extraction time on LPME performance was investigated first. The solvents of 2-nonanone and 2-nitrophenyl octyl ether (NPOE) were found to be stable and efficient SLMs for LPME of diphenidol from biofluids and tissue samples, respectively. At steady state, the LPME recoveries for different sample matrices were in the range of 87 %-91 %. Due to the clean-up capability of LPME and the relatively high concentration of diphenidol in the fatal poisoning case, the proposed LPME systems were validated with related sample matrices using HPLC-UV for the determination. The methods displayed good linearity (R² ≥ 0.9943), and the limits of detection were 0.30 mg L-1, 0.28 mg L-1, and 2.7 μg g-1 for blood, urine, and liver samples, respectively. Meanwhile, the precision (≤13%), accuracy (90-110%), and matrices effect (±15%) were satisfactory at low, medium, and high concentrations. In addition, the stability, carryover, and dilution integrity met the requirements of ASB Standard 036. Finally, the proposed method was successfully applied to evaluate the biodistribution of diphenidol in five different biofluids, five organs, and six brain regions from a fatal poisoning case. Generally, the distribution of diphenidol in biofluids was lower than that in the organs and brain regions, and the highest concentration of diphenidol was observed in the liver, which is very important for the selection of inspection samples in forensic toxicological analysis. Therefore, LPME was proved to be a powerful tool for the investigation of biodistribution and postmortem redistribution in the fields of forensics.

Electrochemiluminescence of Ru(bpy)32+/thioacetamide and its application for the sensitive determination of hepatotoxic thioacetamide

Thioacetamide (TAA) is a well-known hepatotoxic substance, so it is important to determine its presence and content in food and environmental samples. Herein, we report a highly sensitive determination method for TAA based on the electrochemiluminescence (ECL) of tris(2,2'-bipyridyl)ruthenium(ii) (Ru(bpy)32+) for the first time by using TAA as a new coreactant for Ru(bpy)32+ ECL via an anodic route. The developed Ru(bpy)32+-TAA ECL system allows the determination of TAA with a good dynamic linear range and low limit of detection (LOD) of 0.1 μM to 1000 μM and 0.035 μM (3σ/m), respectively. In addition, the established ECL system can be applied to detect TAA in fruit juice and waste water samples with outstanding recoveries.

Application of a Validated UPLC–MS-MS Method for the Determination of Diphenidol in Biological Samples in 15 Authentic Lethal Cases

Diphenidol (DPN) is a nonphenothiazinic antivertigo and antiemetic drug that has been widely used in clinical practice in China because of its good antivertigo curative effect, minimal side effects and high safety. In recent years, there have been some cases of sporadic suicide and accidental poisoning related to DPN. Hence, a validated method for the determination of DPN in biological samples by ultra-high-performance liquid chromatography tandem mass spectrometry (UPLC–MS-MS) was developed. The method is characterized by the use of a simple, fast and inexpensive liquid–liquid extraction (LLE) for sample preparation, a rapid run time (5 min) and a low required sample volume (0.1 mL or 0.1 g). The lower limits of quantitation (LLOQs) were 0.05 ng/mL and 0.3 ng/g for blood and liver tissue, respectively. The method was shown to be linear over a concentration range of 0.05 ∼ 200 ng/mL (blood) and 0.3 ∼ 400 ng/g (liver). The accuracy was in the range of 92.77% ∼ 112.75%. The relative standard deviations of the intraday and interday imprecisions were in the range of 3.22% to 12.17%, and the recoveries were in the range of 58.75% ∼ 95.27%. Furthermore, the method was successfully applied to the detection and quantification of DPN in 15 real forensic cases. The postmortem concentration range of heart blood was 0.87 ∼ 99 μg/mL.

Electrochemiluminescence Sensor Based on Electrospun Three-Dimensional Carbon Nanofibers for the Detection of Difenidol Hydrochloride

The detection of difenidol hydrochloride, which is a drug that is widely used for treating the nausea and vomiting symptoms caused by certain diseases, has been increasingly involved in cases of suicide via overdosing and of drug poisoning in children. A novel electrochemiluminescence (ECL) sensor for the simple and effective detection of difenidol hydrochloride was fabricated by modifying a glassy carbon electrode with three-dimensional carbon nanofibers (3D-CNFs). The 3D-CNFs were synthesized by electrospinning a mixture of montmorillonite (MMT) and polyacrylonitrile, carbonizing the electrospun product, and etching it with hydrofluoric acid. The form and structure of the 3D-CNFs was analyzed via scanning electron microscopy, X-ray photoelectron spectroscopy, and Raman microspectroscopy. According to the experimental results obtained using the modified electrodes, a good linear relationship was found between peak intensity and difenidol concentration (y = 868.14x − 61.04, R² = 0.999), with a relatively low detection limit (8.64 × 10⁻¹⁰ mol·L⁻¹ (S/N = 3)). In addition, our approach exhibited good recovery values ranging from 98.99% to 102.28%. The proposed novel ECL sensor has wide application prospects for the detection of difenidol hydrochloride.

A novel electrochemiluminescence sensor for the determination of diphenidol based on a nano-TiO2/silica sol/PVP/Ru(bpy)32+ modified gold electrode

Compared with the bare electrode, the sensitizing effect of diphenidol on Ru(bpy)₃²⁺ was obvious on the modified electrode.

Capillary electrophoresis and microchip capillary electrophoresis with electrochemical and electrochemiluminescence detection

Recent advances and key strategies in capillary electrophoresis and microchip CE with electrochemical detection (ECD) and electrochemiluminescence (ECL) detection are reviewed. This article consists of four main parts: CE-ECD; microchip CE-ECD; CE-ECL; and microchip CE-ECL. It is expected that ECD and ECL will become powerful tools for CE microchip systems and will lead to the creation of truly disposable devices. The focus is on papers published in the last two years (from 2005 to 2006).