روش DI-SPME / LC-TOFMS برای تحلیل کارآمد مغز استخوان پس از مرگ
Abstract
1- Introduction
2- Experimental
3- Results and discussion
4- Conclusions
References
Abstract
For the first time the method DI-SPME/LC-TOFMS was used and developed in order to determine the large antidepressant drugs in real forensic cases. The aim of the study was to optimize the new DI-SPME/LC-TOFMS method for the quantification of the large group of psychotropic drugs such as benzodiazepines, selective serotonin reuptake inhibitors, selective serotonin and noradrenaline reuptake inhibitors, tricyclic antidepressants and sleeping pills “Z". The volume of the sample, adsorption time, post-adsorption purification and desorption time were precisely optimized. The validation parameters such as limit of detection and quantification, linearity, precision during and between days and the matrix effect were determined. All obtained values are within the acceptable range for toxicological analyses. The usefulness of the method was confirmed by analyzing the post-mortem samples. Drug concentrations were determined in real samples with high precision, which gives perspectives for the DI-SPME/LC-TOFMS routine application in toxicological and forensic analyses in the future.
Introduction
Due to complicated post-mortem processes that occur in the body after intake of drugs or poisons like redistribution, degradation, and contamination, it is necessary to provide a complex analysis of available body fluids like urine, blood or other alternative materials such as bone marrow. Material which can be helpful in post-mortem investigation is bone marrow aspirate (BMA), which is a semi-liquid form (it can be handled with a pipette) of bone marrow, placed inside the bones [1–3]. However, analysis of alternative materials often carried out with various limitations and compared to that analysis of BMA appears to have few practical advantages. It is a well-preserved post-mortem material, because of the physical barrier provided by cortical bone, which can be easily collected in large amounts and may be used as an alternative material to peripheral venous blood [4–6]. Due to high fat level and blood supply, it is possible to determine psychotropic drugs in bone marrow, which has been confirmed by Snamina et al. [7] with very satisfying results. On the other hand Cartiser et al. [2] provided a comprehensive summary on correlation studies between blood or plasma and bone marrow levels of different xenobiotics. The correlations varied from very low to almost absolute, depending on the drug. The success and application of the method often depend on its capabilities, trueness and also time of whole analysis. Considering extraction of analytes as the most demanding, time-consuming and multistep process it is regarded as a critical process to carry out in the whole analysis. The technique which may facilitate and simplify the extraction of analytes from complex samples like biological materials may be Direct Immersion Solid-Phase Micro Extraction (DI-SPME) [8–10]. It is an extraction technique based on the sorption of analytes on the stationary phase of fused silica, placed on the solid support. The DI-SPME procedure is based on the exposure of the fiber to the sample for sufficient time. This technique integrates extraction, concentration and analyte desorption into a single procedure [11,12]. As the technique is reducing sample handling, solvent use, time and cost it is prosperous for toxicological and forensic analysis. Due to the wide selection of fiber coatings and its sorption capabilities DI-SPME extraction is also used in food and environmental analyses, as well as studies for its in vivo application are carried out. The initial application of the DI-SPME technique in drug analysis was for psychotropic substances. Moreover, in recent years the increase of DI-SPME applications was observed with connection of liquid chromatography and capillary electrophoresis [13,14].