A quick method for determination of psychoactive agents in serum and hair by using capillary electrophoresis and mass spectrometry

Laser-scribing fabrication of a disposable electrochemical device for forensic detection of crime facilitating drugs in beverage samples

A portable and disposable laser-scribed graphene (LSG) device was fabricated on polyetherimide (PEI) substrate for electrochemical detection of benzodiazepines (BZ) drugs such as diazepam (DZ) and midazolam (MZ) in commercial beverage samples. Morphological characterizations of the LSG material recorded by scanning electron microscopy (SEM) revealed the porous nature of the proposed electrochemical device, which contributed to the enhancement of the electroactive area. Besides, the structural and electrochemical characterizations performed by Raman spectroscopy, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) measurements revealed that the PEI-LSG material presents highly disordered graphene-like structures and high electron transfer features, respectively. The electrochemical detection of DZ and MZ was carried out by Square Wave Voltammetry (SWV), whose analytical curves exhibited two linear intervals in concentrations ranging from 2.5 μmol L^-1 to 25.0 μmol L^-1 and from 25.0 μmol L^-1 to 100.0 μmol L^-1 for both BZ. We obtained limits of detection (LOD) and quantification (LOQ) of 0.66 and 2.18 μmol L^-1 for DZ and 0.61 μmol L^-1 and 2.01 μmol L^-1 for MZ, respectively. The developed sensor was applied to detect DZ and MZ in commercial beverages such as juice, whisky, and sugarcane spirit samples to mimic potential forensic evidence of drug-facilitated crimes. The recoveries ranged from 97.1% to 117.2% for DZ and from 92.2% to 114.3% for MZ. In addition, the proposed method presented high manufacturing reproducibility (relative standard deviation (RSD) = 2.18% for DZ and RSD = 3.82% for MZ, n = 8 sensors) and adequate selectivity, highlighting the potential of PEI-LSG sensor as an excellent alternative method for forensic detection of crime facilitating drugs in commercial beverage samples.

Development of a new method for drug detection based on a combination of the dried blood spot method and capillary electrophoresis

The aim of this study was to develop a new approach to sample preparation of biological material based on a combination of the Dried Blood Spot (DBS) method and capillary electrophoresis coupled with mass spectrometry (CE-MS) for the analysis of blood samples collected in vivo or post-mortem. The proposed approach allowed the identification of typical drugs from different groups, such as tricyclic antidepressants (amitriptyline, imipramine), selective serotonin reuptake inhibitors (citalopram), benzodiazepines (tetrazepam) and hypnotics (zolpidem). In this study, a blood sample was spotted on FTA DMPK C cards, then dried, and 6-mm discs were cut out. The sample preparation procedure involved microwave-assisted extraction (MAE). Various extraction agents, temperatures and durations of extraction were examined in order to achieve the highest efficiency of the process. The method was subjected to a validation procedure. Limits of detection (LOD = 1.76 - 14.7 ng/mL) and quantification (LOQ = 5.25 - 49.0 ng/mL), inter- (CV = 1.31 - 9.43%) and intra- (CV = 3.26 - 18.52%) day precision of the determinations, recovery (RE = 85.0-105.4%) and matrix effect on ionization of analytes (ME = 98.6-105.5%) were determined. Furthermore, the developed DBS/MAE/CM-MS method was selective and analytes present in the blood applied on DBS cards were found to be stable after 7 and after 14 days. Moreover, the developed method was successfully applied to the analysis of both post-mortem samples and blood samples taken from patients treated with the analyzed drugs.

A batch and cloud point extraction kinetic spectrophotometric method for determining trace and ultra trace amounts of Benzodiazepine drugs (Clonazepam and Nitrazepam) in pure and pharmaceutical preparations

Utilizing the batch Diazotization coupling reaction and the cloud point extraction kinetic spectrophotometric method, trace and Ultra trace amounts from reducing Nitrazepam and Clonazepam were evaluated by way of using 2,5-dimethoxyaniline as a new Chromogenic reagent to give colored products (red) in acidic medium which have a maximum absorption at 500 and 502 nm, respectively. In the work, the analytical data of batch and cloud point for Nitrazepam and Clonazepam depended on initial rate and fixation time. This involved concentrations of (0,3-9), (0.05-1.2), (0.5-10) and (0.025-1) µg mL−1, as well as molar absorptivity of (3.8×104), (3.1×105) (3.39×104) and (3.47×105) L mol−1 cm−1. According to our results, Sandall’s sensitivity were (0.0074), (0.0009), (0.0092) and (0.0009) µg cm−2, while detection limits were (0.055) and (0.069) µg mL−1, (8.4) and (8.5) ng mL−1. In addition, the measurements enrichment factors were (33.33) and (50), while preconcentration factors were (8) and (9.9), respectively. The reaction of Nitrazepam and Clonazepam with 2,5-dimethoxyaniline were a pseudo first order according to kinetic studies. The proposed methods are not affected by existence of excipients so the methods can be applied successfully for determination of Nitrazepam and Clonazepam in pharmaceutical preparations.

Direct analysis from dried blood spot card surfaces with direct probe mass spectrometry - Evaluation study

RATIONALE

The Direct Probe Mass Spectrometry (DIPMS) method allows successful analysis of powders, solid and liquid samples. The potential of direct surface analysis could find further application in the examination of surfaces with good absorption properties such as Dried Blood Spot (DBS) cards that constitute a great alternative to the classical blood collection method directly from veins.

METHODS

DIPMS was performed with the ionization carried out under atmospheric pressure in an Atmospheric Pressure Chemical Ionization source. Direct analysis of diazepam solutions in methanol and after their deposition onto a DBS card was conducted. Subsequently, images of the DBS cards with and without blood samples were acquired using Scanning Electron Microscopy (SEM).

RESULTS

Direct quantitative analysis of diazepam liquid samples by DIPMS was successfully performed. Linear correlation between the concentration of diazepam and the peak intensity with a R² coefficient of 0.937 was obtained. However, the method failed when the analysis was conducted directly from the surface of the DBS cards and no diazepam peak was observed in the mass spectrum. The SEM images confirmed the good absorption properties of DBS cards and the absence of blood components on the surface.

CONCLUSIONS

DIPMS is an excellent technique for the rapid, direct analysis of powders, solid and liquid samples; however, the potential of the method is limited when samples are deposited on surfaces with good absorption properties such as DBS cards.

Dried blood spots sampling in case samples deprived of hematocrit level information - Investigation and calculation strategy

The application of a new calculation strategy for the psychotropic drug concentration in blood and bone marrow samples in the form of dried blood spots (DBS) was the main aim of the study. The standard DBS method consists of the deposition of the capillary blood onto the dedicated paper cards. Nowadays, the DBS technique is seen as a fast and partly superior microsampling alternative methodology replacing the conventional venous blood and plasma collection. The calculation approach to drug concentration in the limited volume of the case sample, where the hematocrit level cannot be determined, constitutes an important step of this method. The method has been validated and the results of the determination of alprazolam and diazepam previously spiked in the post-mortem blood and bone marrow sample have been satisfactory.