Development and Validation of a Rapid Method for Identification of New Synthetic Cannabinoids in Hair Based on High-Performance Liquid Chromatography-Ion Trap Mass Spectrometry Using a Simplified User Interface.

The penetration of the new psychoactive substances (NPSs) into the market of clandestine drugs is highly dynamic, causing potentially false-negative results using the current analytical instrumentation, particularly in the screening phase. At present, the suggested approach to perform a comprehensive screening requires the use of high-resolution mass spectrometry (MS) with associated high costs of purchase and maintenance and need of skilled and dedicated personnel. Here we describe the development and validation of a simplified approach based on a high-performance liquid chromatography-ion trap MS system with a user-friendly interface dedicated to toxicological analysis. The system, originally intended for a broad toxicological screening, was tuned to identify new synthetic cannabinoids in hair. After a washing step with dichloromethane, hair (about 50 mg) was incubated for 3 h with 1.5 mL ethanol. One milliliter of this solution was then dried, reconstituted with mobile phase and injected. The peak identification was based on the chromatographic retention times and MS2/MS3 data using a database which included up to 158 NPSs. The method was validated according to international guidelines on a selected panel of NPSs, namely methyl 2-[[1-(5-fluoropentyl)indazole-3-carbonyl]amino]-3,3-dimethylbutanoate (5F-ADB), 1-Pentyfluoro-1H-indole-3-carboxylic acid 8-quinolinyl ester (5F-PB 22), N-[(2S)-1-amino-3-methyl-1-oxobutan-2-yl]-1-(5-chloropentyl)indazole-3-carboxamide (5Cl-AB-PINACA), (S)-N-(1-amino-1-oxo-3-phenylpropan-2-yl)-1-(5-fluoropentyl)-1H-indole-3-carboxamide [5F-APP-PICA (PX-1)],: (R)-N-(1-amino-1-oxo-3-phenylpropan-2-yl)-1-(5-fluoropentyl)-1H-indazole-3-carboxamide [5F-APP-PINACA (PX-2)], N-[(2S)-1-Amino-3-methyl-1-oxobutan-2-yl]-1-(cyclohexylmethyl)indazole-3-carboxamide (AB-CHMINACA), N-[(2S)-1-Amino-3-methyl-1-oxobutan-2-yl]-1-[(4-fluorophenyl)methyl] indazole-3-carboxamid (AB-FUBINACA), methyl (2S)-2-[[1-(cyclohexylmethyl)indole-3-carbonyl]amino]-3,3-dimethylbutanoate (MDMB-CHMICA), (S)-Methyl 2-(1-(5-fluoropentyl)-1H-indole-3-carboxamido)-3-methylbutanoate (MMB-2201) and (1-pentylindol-3-yl)-(2,2,3,3-tetramethylcyclopropyl)methanone (UR-144). The tested analytical method showed detection limits between 0.065 and 0.125 ng/mg. The intraday imprecision of the method showed average values within the range of 7.3-20%. The estimation of the trueness (bias) of method showed average values within the range of 1.5-12.3%. The analytical performance was also successfully assessed by four proficiency test samples containing NPS. No synthetic cannabinoids were detected in application to 82 hair samples from forensic cases previously analyzed with liquid chromatography-MS triple quadrupole.

Simultaneous analysis of potassium and ammonium ions in the vitreous humour by capillary electrophoresis and their integrated use to infer the post mortem interval (PMI).

Post-mortem changes of ions in the body fluids have been proposed as an objective tool for inferring the time of death. In particular, the post-mortem increase of potassium concentrations in the vitreous humour has gained great attention in the literature. On the other hand, ammonium, another ion released in post-mortem processes, has received much less attention, potentially due to unresolved analytical issues using current clinical chemistry methods. This paper presents an application of a new analytical approach based on capillary electrophoresis providing the simultaneous analysis of potassium and ammonium ions in the vitreous humour. In addition, to assess the consistency of the post-mortem increase of ammonium concentrations in the vitreous humour, the determination of this ion in the vitreous humour of the two eyes of the same body at the same post-mortem interval has been verified. Vitreous humour was collected from 33 medico-legal cases where the time of death was known exactly. Prior to analysis, all samples were diluted 1:20 with a 40 µg/mL solution of BaCl2 (internal standard). In the study of the variability of the ammonium concentration between the two eyes, no statistically significant differences were found, supporting the hypothesis of an even post-mortem increase of the ion concentrations in this particular biological fluid. Significant correlations of potassium and ammonium ions with the post-mortem interval were found, with r2 of 0.75 and 0.70, respectively.

Development of a low cost gas diffusion device for ammonia detection in the vitreous humor and its preliminary application for estimation of the time since death.

A simple and low cost analytical device is described for the determination of ammonium in the vitreous humor suitable for inferring the post mortem interval in forensic cases. The device is based on ammonia formation from ammonium ion by means of NaOH addition to the vitreous humor sample and its detection with a pH chemical indicator in the gas phase above the vitreous humor sample. From the gas phase, ammonia diffuses through a polymeric membrane and it is trapped and detected with a droplet of pH indicator thymol blue. The color change of the droplet is measured using a smartphone camera. Under optimal conditions, the device showed a limit of detection of 0.2mM, with between days precision of ≤ 15% expressed as relative standard deviation, and an accuracy between days from 88.3% to 114.5%. This homemade gas diffusion analytical device was successfully used for the determination of ammonia in vitreous humor samples from forensic autopsies. The results obtained with the proposed method, although for a limited number, showed a close correlation with the data obtained with an instrumental analysis based on capillary electrophoresis. Moreover a significant correlation was also found between the results of the present method and the time elapsed since death by a simple evaluation of the color intensity. In conclusion, this preliminary study showed that the proposed device, after adequate validation, could be a promising tool for a presumptive estimation of the time since death directly at the crime scene.

A new method for the determination of ammonium in the vitreous humour based on capillary electrophoresis and its preliminary application in thanatochemistry.

Background Although the post-mortem increase of ammonium in biological fluids is well known, ammonium analysis in vitreous humour has never been used in recent times for the determination of the post-mortem interval. The present work represents a new application of capillary electrophoresis with indirect UV detection in the field of forensic analysis. Methods The electrophoretic separation was carried out in a running buffer made of 5 mM imidazole, 5 mM 18-crown-6 ether and 6 mM d,l-α-hydroxybutyric acid (HIBA). To overcome the lack of optical absorption of ammonium, indirect UV detection was applied. The used wavelength was 214 nm. Results The method showed good linearity in the concentration range from 0.16 to 5.0 mM. The limit of detection, 0.039 mmol/L, was established on the basis of the linearity curve. Precision and bias studies carried out on the pure ammonium solutions and in real biological samples, revealed %RSDs well below 20%. A preliminary application to real cases where the death time was precisely known (14 bodies) was carried out plotting vitreous humour ammonium vs. post-mortem interval with a resulting good linear correlation until 100 h post-mortem. Conclusions After validation in real cases, the present method can become a powerful tool to unravel one of the most challenging issues of forensic investigation: determination of the time of death.