Caiqin Han
Jiangsu Normal University
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Publication
Featured researches published by Caiqin Han.
Talanta | 2014
Caiqin Han; Jing Chen; Xiaomeng Wu; Yao-wen Huang; Yiping Zhao
In this study, the surface enhanced Raman spectra (SERS) of two prohibited veterinary drugs, metronidazole (MNZ) and ronidazole (RNZ), have been acquired, and compared to the theoretically calculated spectra using density function theory (DFT). The experimental Raman and SERS spectra of MNZ and RNZ exhibit high resemblance with the DFT calculations. SERS detection of MNZ and RNZ from standard solutions as well as real environmental samples (tap, lake, swamp waters and soil) was performed on highly sensitive and reproducible silver nanorod array substrates. The limits of detection for MNZ and RNZ are 10 and 1 µg/mL in methanol and ultra-pure water, respectively, and 10-50 µg/mL in the environmental samples. The SERS-based method demonstrates its potential as a rapid, simple, and inexpensive means for the onsite screening of banned antibiotics from the aquatic and sediment environments, with minimal requirement for sample pretreatment.
PLOS ONE | 2016
Jie Cheng; Xiao-Ou Su; Yue Yao; Caiqin Han; Shi Wang; Yiping Zhao
There is an urgent need for rapid and reliable methods able to detect melamine in animal feed. In this study, a quick, simple, and sensitive method for the determination of melamine content in animal feed was developed using surface-enhanced Raman spectroscopy on fabricated Ag nanorod (AgNR) array substrates with a one-step sample extraction procedure. The AgNR array substrates washed by HNO3 solvent (10−7 M) and methanol and showed the good stability within 6 months. The Raman shift at △ν = 682 cm−1 was used as the characteristic melamine peak in the calculations. Sufficient linearity was obtained in the 2–200 μg·g−1 range (R2 = 0.926). The limits of detection and quantification were 0.9 and 2 μg·g−1, respectively. The recovery rates were 89.7–93.3%, with coefficients of variation below 2.02%. The method showed good accuracy compared with the tradition GC-MS analysis. This new protocol only need 2 min to fininsh the detection which could be developed for rapid onsite screening of melamine contamination in quality control and market surveillance applications.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy | 2018
Yue Yao; Wen Wang; Kangzhen Tian; Whitney Ingram; Jie Cheng; Lu-Lu Qu; Haitao Li; Caiqin Han
Allura Red (AR) is a highly stable synthetic red azo dye, which is widely used in the food industry to dye food and increase its attraction to consumers. However, the excessive consumption of AR can result in adverse health effects to humans. Therefore, a highly reproducible silver nanorod (AgNR) array was developed for surface enhanced Raman scattering (SERS) detection of AR in candy. The relative standard deviation (RSD) of AgNR substrate obtained from the same batch and different batches were 5.7% and 11.0%, respectively, demonstrating the high reproducibility. Using these highly reproducible AgNR arrays as the SERS substrates, AR was detected successfully, and its characteristic peaks were assigned by the density function theory (DFT) calculation. The limit of detection (LOD) of AR was determined to be 0.05 mg/L with a wide linear range of 0.8-100 mg/L. Furthermore, the AgNR SERS arrays can detect AR directly in different candy samples within 3 min without any complicated pretreatment. These results suggest the AgNR array can be used for rapid and qualitative SERS detection of AR, holding a great promise for expanding SERS application in food safety control field.
Journal of Chromatography A | 2018
Lu-Lu Qu; Qin Jia; Chunyuan Liu; Wen Wang; Lingfeng Duan; Guo-Hai Yang; Caiqin Han; Haitao Li
A fast and facile method was developed for on-site detection of aflatoxins (AFs) in moldy agricultural products using thin layer chromatography combined with surface-enhanced Raman spectroscopy (TLC-SERS). Four different AFs were successfully separated by TLC and then a small portable Raman spectrometer, with gold colloids as the SERS-active substrate, was applied to identify the separated spots. TLC-SERS application to on-site detection of AFs was systematically investigated. Qualitative and quantitative AF detection was found to be easily accomplished and limits of detection were estimated to be 1.5 × 10-6, 1.1 × 10-5, 1.2 × 10-6, and 6.0 × 10-7 M for AFB1, AFB2, AFG1, and AFG2, respectively. The proposed method was also highly selective, enabling successful AF identifications in complex extracts from moldy peanuts. The study showed that TLC-SERS could be effectively used for separation and detection of these four AFs, demonstrating good prospects for on-site qualitative screening of agricultural products.
Optics Express | 2017
Rong-Yuan Zou; Jun-Xian Shi; Hong-Kai Dai; Hong-Feng Wang; Lin-Yong Qian; Xing-Hai Wang; Caiqin Han; Changchun Yan
We report a plasmonic structure for switchable reflection and transmission by polarization. The structure is composed of a hexagonal-packed polystyrene sphere array with silver patches on them. Simulations and experiments demonstrated that the conversions between reflected beams and transmitted ones can be performed when the polarization directions of incident beams vary from 0° to 90°. A switchable reflection and transmission at a given wavelength can be obtained, as long as sizes of PS spheres and azimuthal angles are properly chosen. Such a patchy plasmonic structure serving as a switch between reflection and transmission have potential applications in photoelectric control devices.
IEEE Photonics Technology Letters | 2017
Lin-Yong Qian; Kangni Wang; Caiqin Han
In this letter, we experimentally demonstrate a compact and tunable guided-mode resonance (GMR) filter incorporates a varied-line-spacing (VLS) grating layer that is fabricated using holographic interference lithography. The reflectance wavelength varies as a function of the spatial position on the structure. In an interference exposure system, a cylindrical lens is placed between the collimating mirror and the sample to achieve a VLS grating at different positions on the photo-resist film. The grating period increment is approximately 108 nm over a length of 22 mm, which results in a primary reflectance peak that spans 762.1–908.3 nm. The device is designed using the rigorous coupled-wave analysis method, and the proposed device is directed toward the practical application of GMR tunable filters.
Journal of Physical Chemistry C | 2015
Whitney Ingram; Caiqin Han; Qiuju Zhang; Yiping Zhao
Sensors and Actuators B-chemical | 2017
Caiqin Han; Yue Yao; Wen Wang; Lu-Lu Qu; Layne Bradley; Shulin Sun; Yiping Zhao
JOM | 2016
Xiaomeng Wu; Caiqin Han; Jing Chen; Yao-wen Huang; Yiping Zhao
Mikrochimica Acta | 2017
Caiqin Han; Yuqi Li; Qin Jia; Layne Bradley; Yun Gan; Yue Yao; Lu-Lu Qu; Haitao Li; Yiping Zhao