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Determination of Acrylamide in Foods by Solid Phase Microextraction-Gas Chromatography
Liangbi Chen,Haizhu Liu,Ping Yu,Jinyun Zhao,Xi Chen 한국식품과학회 2009 Food Science and Biotechnology Vol.18 No.4
A new approach for the determination of acrylamide (AM) in foods by solid phase microextraction-gas chromatography (SPME-GC) was established. AM was bromized and transformed to 2-bromoacrylamide (2-BAM). 2-BAM was then extracted by a commercial SPME fiber, 75-㎛ Car/PDMS fiber, for GC detection. The influence of extraction and desorption parameters such as extraction temperature and time, stirring rate, desorption temperature, and time were studied and optimized. The mass concentration was proportional to the peak area of 2-BPA from 1.0 to 8,000 ㎍/ℓ. The detection limit of the SPME-GC for 2-BAM was found to be 0.1 ㎍/ℓ, and the recoveries and relative standard deviations for different food samples were 74.5 to 102.0%, and 4.2 to 9.1%, respectively. The presented method was applied to the determination of AM in fried foods.
Jingbin Zeng,Jinmei Chen,Wenfeng Chen,Xiaoli Huang,Liangbi Chen,Xi Chen 한국식품과학회 2009 Food Science and Biotechnology Vol.18 No.3
Solid-phase microextraction (SPME) has gained widespread acceptance in sample pretreatment due to its solventfree and easy-to-operate properties. SPME fibers are considered as a key part of SPME technique, since it primarily determines the extraction performance of the method including sensitivity, selectivity, and reproducibility. Generally speaking, target analyte with different chemical property requires fiber coating that has the best affinity towards it. Due to the lack of varieties of commercial fibers available currently, considerable efforts have been recently made to develop tailor-made fibers to fulfill increasing demands of different analysis. This paper concisely classify some SPME fiber preparation approaches such as solgel technology, physical deposition, molecularly imprinted technique, and their respective application in food safety analysis.
Huang, Xi,Ouyang, Xinhao,Yang, Panyu,Lau, On Sun,Chen, Liangbi,Wei, Ning,Deng, Xing Wang National Academy of Sciences 2013 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.110 No.41
<P>The evolutionarily conserved CONSTITUTIVE PHOTOMORPHOGENESIS 1 (COP1) is a RING and WD40 protein that functions as a substrate receptor of CULLIN4–DAMAGED DNA BINDING PROTEIN 1 (CUL4–DDB1)–based E3 ubiquitin ligases in both plants and animals. In <I>Arabidopsis</I>, COP1 is a central repressor of photomorphogenesis in the form of COP1–SUPPRESSOR OF PHYA (SPA) complex(es). CUL4–DDB1–COP1–SPA suppresses the photomorphogenic program by targeting the transcription factor ELONGATED HYPOCOTYL 5 for degradation. Intriguingly, under photomorphogenic UV-B light, COP1 reverses its repressive role and promotes photomorphogenesis. However, the mechanism by which COP1 is functionally switched is still obscure. Here, we demonstrate that UV-B triggers the physical and functional disassociation of the COP1–SPA core complex(es) from CUL4–DDB1 and the formation of a unique complex(es) containing the UV-B receptor UV RESISTANCE LOCUS 8 (UVR8). The establishment of this UV-B–dependent COP1 complex(es) is associated with its positive modulation of ELONGATED HYPOCOTYL 5 stability and activity, which sheds light on the mechanism of COP1’s promotive action in UV-B–induced photomorphogenesis.</P>