Determination of Salt Forms of New Psychoactive Substances by Ion Chromatography / 法医学杂志

Objective To establish an ion chromatography method for the salt form determination of new psychoactive substances （NPS）. Methods The method of conducting qualitative and quantitative analysis of six types of organic acid ions （acetate ion, tartrate ion, maleate ion, oxalate ion, fumarate ion, citrate ion） and five types of inorganic anions （fluoride ion, chloride ion, nitrate ion, sulfate ion, phosphate ion） in NPS sample by ion chromatography was developed. The salt forms of 222 seized NPS samples （103 samples with synthetic cannabinoids, 81 samples with cathinones, 44 samples with phenylethylamines, 12 samples with tryptamines, 7 samples with phencyclidines, 6 samples with piperazines, 2 samples with aminoindenes, 26 samples with fentanyls and 43 samples with other types of NPS） were analyzed by this method. Results Each anion had good linearity in the corresponding linear range, the correlation coefficients （r） were greater than 0.999, the limits of detection were 0.01-0.05 mg/L, and the limits of quantitative were 0.1-0.5 mg/L. Except that 5F-BEPIRAPIM was hydrochloride, the salt forms of the other 102 synthetic cannabinoids were all base. The salt form of 81 cathinone samples, 44 phenylethylamine samples, 7 phencyclidine samples and 2 aminoindene samples were all hydrochloride. The salt forms of tryptamine samples included base, hydrochloride, fumarate and oxalate. The salt forms of piperazine samples included base and hydrochloride. The salt forms of fentanyl samples and samples of other types included base, hydrochloride and citrate. Conclusion Ion chromatography is a simple, accurate and efficient method for determining the salt form of NPS samples, which makes the qualitative and quantitative conclusions of NPS more scientific and rigorous.

Identification of Synthetic Cannabinoid 5F-EDMB-PICA in Suspicious Herbal Products / 法医学杂志

Objective To study the qualitative analysis strategy for unknown synthetic cannabinoid in the suspicious herbal product when no reference substance is available. Methods The synthetic cannabinoid in herbal blend was extracted with methanol. The extract was concentrated by rotary evaporator and separated and purified by preparative liquid chromatography, to obtain high purity synthetic cannabinoid sample. Gas chromatography-mass spectrometry （GC-MS）, ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry （UPLC-QTOF-MS） and nuclear magnetic resonance （NMR） were used to determine the structure of the prepared compound. Results High purity unknown sample （10 mg） was obtained by preparative liquid chromatography. The sample was analyzed by GC-MS, UPLC-TOF-MS and NMR, and through spectrum analysis, the unknown synthetic cannabinoid was determined as 5F-EDMB-PICA. Conclusion The method to extract unknown synthetic cannabinoid from low content herbal products by preparative liquid chromatography was established, and the structure of the unknown sample was identified by comprehensive use of GC-MS, UPLC-QTOF-MS and NMR. The information will assist forensic laboratories in identifying this substance or other compounds with similar structures in their casework.

Rapid Qualitative and Quantitative Analysis of Caffeine and Sodium Benzoate in Annaca by Infrared Spectroscopy / 法医学杂志

Objective To establish an infrared spectroscopic method for the rapid qualitative and quantitative analysis of caffeine and sodium benzoate in Annaka samples. Methods Qualitative and quantitative modeling samples were prepared by mixing high-purity caffeine and sodium benzoate. The characteristic absorption peaks of caffeine and sodium benzoate in Annaka samples were determined by analyzing the infrared spectra of the mixed samples. The quantitative model of infrared spectra was established by partial least squares （PLS）. Results By analyzing the infrared spectra of 17 mixed samples of caffeine and sodium benzoate （the purity of caffeine ranges from 10% to 80%）, the characteristic absorption peaks for caffeine were determined to be 1 698, 1 650, 1 237, 972, 743, and 609 cm-1. The characteristic absorption peaks for sodium benzoate were 1 596, 1 548, 1 406, 845, 708 and 679 cm-1. When the detection of all characteristic absorption peaks was the positive identification criteria, the positive detection rate of caffeine and sodium benzoate in 48 seized Annaka samples was 100%. The linear range of PLS quantitative model for caffeine was 10%-80%, the coefficient of determination （ R2） was 99.9%, the root mean square error of cross validation （RMSECV） was 0.68%, and the root mean square error of prediction （RMSEP） was 0.91%; the linear range of PLS quantitative model for sodium benzoate was 20%-90%, the R2 was 99.9%, the RMSECV was 0.91% and the RMSEP was 1.11%. The results of paired sample t test showed that the differences between the results of high performance liquid chromatography method and infrared spectroscopy method had no statistical significance. The established infrared quantitative method was used to analyze 48 seized Annaka samples, the purity of caffeine was 27.6%-63.1%, and that of sodium benzoate was 36.9%-72.3%. Conclusion The rapid qualitative and quantitative analysis of caffeine and sodium benzoate in Annaka samples by infrared spectroscopy method could improve identification efficiency and reduce determination cost.

Structure Analysis and Characterization of Aminorex Analogue 4'-F-4-MAR / 法医学杂志

Objective To study the identification method for 4'-F-4-methylaminorex （4'-F-4-MAR） in samples without reference substance. Methods Gas chromatography-mass spectrometry （GC-MS）, ultra-high-performance liquid chromatography-quadrupole time-of-flight-mass spectrometry （UPLC-QTOF-MS）, nuclear magnetic resonance （NMR） and Fourier transform infrared （FTIR） were comprehensively used for the structure identification of 4'-F-4-MAR in samples. Results Under the positive electrospray ionization （ESI+） mode, quasi-molecular ion in the first order mass spectrometry of the unknown compound was 195.092 6 and its molecular formula was inferred to be C10H11FN2O. The fragment ions in the mass spectrometry of the unknown compound were compared with the related fragment ions of 4,4'-dimethylaminorex （4,4'-DMAR） in literature. It was found that the main fragment ions of the unknown compound were all 4 bigger than the corresponding fragment ions of 4,4'-DMAR. Therefore, the unknown compound was inferred to be a 4,4'-DMAR analogue with a methyl substituted by a fluorine in the benzene ring. The equivalent protons at δ=7.30 and δ=7.06 in 1H-nuclear magnetic resonance （1H-NMR） spectra and the characteristic spin-spin coupling constants （1JC-F=245.2 Hz, 2JC-F=21.3 Hz, 3JC-F=8.1 Hz） for 13C-19F interactions in carbon spectra, further proved that the fluorine substituted methyl at the para-position of the benzene ring. Finally, the unknown compound was determined as 4'-F-4-MAR. Conclusion A method that comprehensively used the identification materials 4'-F-4-MAR in GC-MS, UPLC-QTOF-MS, NMR and FTIR is established and the fragmentation mechanism of fragmentation ions of 4'-F-4-MAR created under the two modes -- electron impact （EI） and electrospray ionization under collision induced dissociation （ESI-CID） is deduced. The information will assist forensic science laboratories in identifying this compound or other substances with similar structure in their case work.

Trend of incidence of surgical site infection following oral and maxillofacial surgery during 11 years / 中国感染控制杂志

Objective To understand the changing trend of incidence of surgical site infection (SSI) following oral and maxillofacial surgery, and explore the influence of American Society of Anesthesiologists (ASA) score, type of incision, duration of operation and surgical risk index.Methods Data of patients who were hospitalized and underwent oral and maxillofacial surgery in a tertiary dental hospital from 2007 to 2017 were retrospectively analyzed. Trend Chi-square test was used to analyze the changing trend of incidence of SSI, binary logistic regression was used to analyze the risk of SSI.Results From 2007 to 2017, incidence of SSI in patients with oral and maxillofacial surgery was 0.33％-0.93％, with an average of 0.71％; patients with high indexes of ASA score, type of incision, duration of operation and surgical risk had higher incidence and risk of SSI; incidence of SSI was the lowest in 2009. In patients with ASA score of P1, surgical risk index of grade 1, incidence of SSI declined from 0.72％ and 2.79％ in 2011 to 0.42％ and 1.54％ in 2017 respectively, with a decrease of more than 41％.Conclusion Incidence of SSI following oral and maxillofacial surgery decreased and finally remained at a low level during 11 years, with the increase of ASA score, risk indexes score of surgical incision type, duration of surgery and surgical risk, incidence and risk of SSI increased gradually, medical environment may be one of the factors that affected SSI.

Mass Spectral Character of Fentanyl Analogues / 法医学杂志

Objective To provide the reference for the identification of unknown fentanyl analogues by studying the characteristic ions and main fragmentation pathways of fentanyl analogues in the modes of collision induced dissociation （CID） and electron ionization （EI）. Methods Nine fentanyl analogues （2, 2'-difluorofentanyl, acetyl fentanyl, fentanyl, butyl fentanyl, valeryl fentanyl, acryloyl fentanyl, furan fentanyl, 4-fluorine isobutyl fentanyl, carfentanyl） were selected and analyzed with ultra-high performance liquid chromatography-quadrupole time-of-flight-mass spectrometry （UHPLC-QTOF-MS） and gas chromatography-mass spectrometry （GC-MS）. The mass spectrum obtained was analyzed. The CID and EI fragmentation routes of fentanyl analogues were speculated. Results The CID and EI fragmentation pathways were highly similar. In the CID mode, characteristic ions were formed by the carbon-nitrogen bond cleavage between the piperidine ring and the N-phenyl-amide moiety, within the piperidine ring, and between the phenethyl and piperidine ring. While in the EI mode, dissociation of the piperidine ring, as well as cleavage between the piperidine ring and the phenethyl were the main fragmentation pathways. Conclusion This study summarizes the main fragmentation pathways and characteristic ions of fentanyl analogues in the CID and EI modes, which is useful for forensic laboratories to identify and structural analyze fentanyl type new psychoactive substance in practical work.