Identification of Synthetic Cannabinoid New Psychoactive Substances 4F-MDMB-BUTINACA and MDMB-4en-PINACA / 法医学杂志

Objective To establish a method that combines a series of techniques including Fourier transform infrared spectrum （FTIR）, gas chromatography-mass spectrometry （GC-MS）, high resolution mass spectrometry and nuclear magnetic resonance spectroscopy （NMR） for identification of unknown substances. Methods The unknown samples （off-white powder and yellow crystal） seized in the actual cases were detected by FTIR, GC-MS （methanol as solvent）, high resolution mass spectrometry （methanol as solvent） and NMR （deuterated methanol as solvent）. Results The mass spectrum characteristic ions m/z of the main components in the samples measured by GC-MS were 219 （base peak）, 363, 307, 304, 275, 145, 131 and 213 （base peak）, 357, 301, 298, 269, 185, 171, 145 and 131, respectively. The accurate mass numbers [M+H]+ measured by high resolution mass spectrometry were 364.203 61 and 358.212 34, respectively. The unknown samples were identified as synthetic cannabinoid new psychoactive substances 4F-MDMB-BUTINACA and MDMB-4en-PINACA after data consultation and database retrieval and comparison, combined with infrared analysis and mass spectrometry data analysis, and their structures were confirmed by 1H-NMR. Conclusion The established multi-technology joint identification method can be used to identify 4F-MDMB-BUTINACA and MDMB-4en-PINACA in unknown samples. This method is fast, convenient, accurate, reliable and practical, and can provide reference for the identification of cases involving such substances in the future.

Determination of Azide Ions in Blood by Pentafluorobenzyl Derivation Followed by GC-MS / 法医学杂志

Objective To establish a method for determination of the azide ions in blood by gas chromatography-mass spectrometry （GC-MS） following pentafluorobenzyl derivatization. Methods A blood sample of 0.2 mL was placed into a 10 mL glass test tube, and the internal standard sodium cyanide, derivatization reagent pentafluorobenzyl bromide and catalyst tetradecyl benzyl dimethyl ammonium chloride were added in turn. After vortex mixing, the mixture was heated with low-power microwave for 3 min. After centrifugation, the organic phase was taken for GC-MS analysis. Results The azide ions in blood had a good linear relationship in the mass concentration range of 0.5 to 20 μg/mL. The lowest detection limit was 0.25 μg/mL and the relative recovery was 91.36%-94.58%. The method was successfully applied to a case of death from sodium azide poisoning. The mass concentration of azide ions in the blood of the dead was 11.11 μg/mL. Conclusion The method developed in this paper has strong specificity and is easy to operate, which is suitable for the rapid detection of azide ions in blood.

Identification of the New Psychoactive Substance Dibutylone / 法医学杂志

Objective To establish a method to identify unknown samples based on combined use of gas chromatography-mass spectrometry （GC-MS）, high resolution mass spectrometry （HRMS） and nuclear magnetic resonance spectrum （NMR） technique. Methods The unknown samples were dissolved in methanol solution containing internal standard SKF525A and detected by GC-MS and HRMS. The mixed samples were separated and purified by silica gel column chromatography, and then dissolved in methanol-d4 solution for structural analysis of 1H nuclear magnetic resonance spectroscopy （1H NMR）. Results The characteristic fragment ions （m/z） were 86.1 （base peak）, 71.2, 121.1, and 149.0, and the accurate mass number of molecular ion peak was measured by HRMS to be 236.128 89. By combined use of data analysis and database comparison, a new psychoactive substance of the cathinone class, Dibutylone, was detected in the sample, and the sample also contained a small amount of caffeine. The sample was purified, then identified using 1H NMR, and was further confirmed to be Dibutylone. In addition, the GC-MS retention time and characteristic fragment ions of the main components of the sample were consistent with those of Dibutylone reference material. Conclusion The method established in this study can be used for the identification of Dibutylone in mixed samples.

DNA aptamer selection in vitro for determining ketamine by FluMag-SELEX / 法医学杂志

OBJECTIVE@#To select specific DNA aptamer for determining ketamine by FluMag-SELEX.@*METHODS@#Based on magnetic beads with tosyl surface modification as solid carrier and ketamine as target, a random ssDNA library with total length of 78 bp in vitro was compounded. After 13 rounds screening, DNA cloning and sequencing were done. Primary and secondary, structures were analyzed. The affinity, specificity and Kd values of selected aptamer were measured by monitoring the fluorescence intensity.@*RESULTS@#Two ssDNA aptamers (Apt#4 and Apt#8) were successfully selected with high and specific abilities to bind ketamine as target with Kd value of 0.59 and 0.66 μmol/L. The prediction of secondary structure was main stem-loop and G-tetramer. The stem was the basis of stability of aptamer's structure. And loop and G-tetramer was the key of specific binding of ketamine.@*CONCLUSION@#FluMag-SELEX can greatly improve the selection efficiency of the aptamer, obtain the ketamine-binding DNA aptamer, and develop a new method for rapid detection of ketamine.