Drug Testing and Analysis
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2020
·Vol. 13
·期 3
·720-728
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IF 2.903
Cui-Mei Liu,Hong-Yuan He,Lin Xu,Zhen-Dong Hua
Performing fast qualitative identification of seized illegal drugs by Raman spectroscopy is challenging due to fluorescence interference as well as chemical complexity. Spectrometers with 785-nm excitation, 1,064-nm excitation, and sequentially shifted excitation (SSE) were compared for their effect on fluorescence reduction. The characteristic peaks method, which is independent of cutting agents, was tested as a new strategy to broaden the application of the Raman technique. The suitability of the characteristic peaks method was fully examined by analyzing a large amount of seized illegal drugs, including 72 methamphetamine hydrochloride (concentration range of 13.9%–99.4%), 68 ketamine hydrochloride (17.7%–99.8%), 176 heroin hydrochloride (5.2%–79.5%), 51 cocaine hydrochloride (21.1%–94.5%), and 33 cocaine base (30.9%–92.5%) samples. The results showed that seized methamphetamine, ketamine, and cocaine samples had no or little fluorescence. Hence, in regard to detection of these samples, the advantage of using 1,064-nm excitation and SSE compared with 785-nm excitation was quite limited. Regarding the heroin samples, a significant improvement of the “high” confident positive detected rate was evident for 1,064 nm excitation (60.8%) and SSE (61.4%), compared with 785-nm excitation (13.1%). However, it was also seen that even if 1,064-nm excitation and SSE were applied, the fluorescence of heroin samples was still unable to be fully overcome. By using the characteristic peaks method, low LOD results of 5%–20% were acquired for 40 types of drug mixtures, and lower LODs were obtained for the 60% of the drug mixtures compared with library searching method. Raman spectroscopy in conjunction with the characteristic peaks method was shown to be fast, simple, accurate, and sensitive in the qualitative analysis of seized drug samples.
研究领域:
分析化学
·
法医学
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产品关联
DOI
PubMed
高影响因子
Chemosensors
·
2022
·Vol. 10
·期 6
·226
·
IF 4.229
Xue Shi,Hua Zhang,Hanyang Ji,Fanli Meng
Volatile organic compounds (VOC) harm human health seriously in the air. Therefore, it is essential to recognize VOC gases qualitatively and quantitatively. The dynamic measurement method can improve the selectivity of metal oxide semiconductor (MOS) gas sensors to VOC, but there is a problem of the insufficient number of characteristic peaks. From the experimental point of view, the primary judgment basis for the correct qualitative and quantitative recognition of VOC gases by the dynamic measurement method is the characteristic peak of the dynamic response signal. However, the traditional dynamic measurement method generally only has two characteristic peaks. In this experiment, the voltage was changed at the time of the second characteristic peak by controlling the constant dynamic response period. Taking ethyl alcohol as an example, the experimental results show that the characteristic peak of the dynamic response signal does not increase when the voltage is constant. However, a new characteristic peak will appear based on a continuously rising heating voltage. The characteristic peaks of the dynamic response of n-propyl alcohol, isopropyl alcohol, and n-butyl alcohol were also increased based on the rising heating voltage waveform. Based on the K-Nearest-Neighbors algorithm, the qualitative and quantitative recognition rate of the four alcohol homologue gases reached 100%.Keywords:dynamic response signal;characteristic peaks;ZnO gas sensor;periodic cycle heating waveform;alcohol homologue gases
研究领域:
传感器技术
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环境科学
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材料科学
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产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Mingyu Yang,Kui Liu,Longcheng Yang,Guoren Yang,Lan Tong,Xianqing Liu,Fang Xu
Herein, first-principles calculations predicted the atomic-scale variation of Sb 5+ substitution for ZnZrTa 2 O 8 , and combined with the solid-phase reaction method to prepare ZnZr(Ta 1- x Sb x ) 2 O 8 (0.0 ≤ x ≤ 0.10) ceramics. ZnZr(Ta 0.94 Sb 0.06 ) 2 O 8 ceramics demonstrated the optimum microwave dielectric properties after sintering at 1350 °C for 6 h: ε r = 24.92, Q × f = 134053 GHz (@7.18 GHz), and τ f = −46.21 ppm/°C. For the non-intrinsic factors, the relative density increased from 96.54 % to 97.74 % and the average grain size increased from 19.88 μm to 21.85 μm, both of which reduced the dielectric loss . Regarding intrinsic factors, the progressive elevation of the Raman characteristic peak wave number and the heightened ionicity of Ta/Sb–O bonds predominantly account for the observed enhancement in εr. In addition, the attenuation of lattice vibrational damping behavior, the augmentation in electron cloud density, and the escalation of lattice energy collectively contribute to a decrement in dielectric loss . This study refines the examination of ionic substitution in ZnZrTa 2 O 8 ceramics, offering theoretical insights for optimizing their dielectric properties and promoting their application in microwave communications.
研究领域:
材料科学
·
物理学
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DOI
高影响因子
JOURNAL OF MOLECULAR STRUCTURE
·
2014
·
IF 1.599
Xiaopei Li,Xiaokun Fan,Kun Huang,Huizhou Liu,Ying Zhao,Yongju Wei,Cuige Liu,Yizhuang Xu,Isao Noda,Jinguang Wu
We explore whether it is possible to use 2D correlation spectrum to characterize intermolecular interactions between two solutes dissolved in the same solution when one substance does not possesses any characteristic peak. We demonstrate that the interaction can be manifested by characteristic cross peaks in 2D asynchronous correlated spectrum. The above cross peaks reflect the subtle spectral variations on the characteristic peak of another solute under intermolecular interaction. On the other hand, 2D synchronous spectrum is not suitable to characterize intermolecular interaction since the cross peaks contain irremovable interfering parts. The terbium-chloride/benzamide/methanol system is used to demonstrate that this approach is applicable in the real chemical system.
研究领域:
分析化学
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光谱学
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产品关联
DOI
高影响因子
RSC Advances
·
2023
·Vol. 13
·期 15
·10135-10143
·
IF 3.9
Yangjie Chen,Juan Hao,Zhihang Yin,Qinghui Wang,Youting Zhou,Lingpu Jia,Huiming Li,Wenlong Liao,Kunping Liu
Internal standard molecule 4-mercaptobenzoic acid (4-MBA) embedded Au core-Ag shell nanorods (Au-MBA@Ag NRs) were prepared by a seed-mediated growth method, then loaded on octahedral MIL-88B-NH2 to obtain a novel ratiometric SERS substrate of Au-MBA@Ag NRs/PSS/MIL-88B-NH2 (AMAPM) for detecting rhodamine 6G (R6G) in chili powder. The porous structure and excellent adsorption ability of MIL-88B-NH2, allowed for increased loading of Au-MBA@Ag NRs, thereby shortening the distance between adsorbed R6G and the “hot spot” resulting from local surface plasmon resonance (LSPR) of Au-MBA@Ag NRs. Based on the SERS characteristic peak ratio of R6G to 4-MBA, the ratiometric SERS substrate displayed improved accuracy and excellent performance for R6G detection, with a wide linear range of 5–320 nM and a low detection limit of 2.29 nM as well as fine stability, reproducibility and specificity. The proposed ratiometric SERS substrate offered a simple, fast and sensitive sensing strategy for R6G detection in chili powder, which demonstrated potential applications in food safety and the analysis of trace analytes in complex matrices.
研究领域:
分析化学
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纳米技术
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食品科学
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光谱学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）