查看“︁荧光淬灭”︁的源代码

[[Image:Quenching of Quinine fluorescence by chloride ions.JPG|thumb|紫外激光（左）照射溶解在水中的两个[[奎宁]]样品。右侧样品发出一般奎宁的蓝色荧光，左侧样品中因为含有[[氯离子]]，可淬灭奎宁的荧光，因此左侧样品不会发出明显的荧光。]]
'''荧光淬灭'''（{{Lang-en|'''Quenching'''}}）是指荧光物质的[[荧光]]强度降低的任何过程。许多过程都会导致淬灭现象，例如[[激发态]]反应、能量转移、[[配合物]]的形成和碰撞淬灭。氧分子、[[碘离子]]和[[丙烯酰胺]]都是常见的化学淬灭剂<ref>''Acrylamide and iodide fluorescence quenching as a structural probe of tryptophan microenvironment in bovine lens crystallins.'' Phillips SR, Wilson LJ, Borkman RF. Curr Eye Res. 1986 Aug;5(8):611-9.</ref>，[[氯离子]]是常见的[[奎宁]]淬灭剂<ref>''Fluorescence experiments with quinine'' James E. O'Reilly J. Chem. Educ., 1975, 52 (9), p 610 {{DOI|10.1021/ed052p610}}</ref><ref>''Photophysics in a disco: Luminescence quenching of quinine'' LouAnn Sacksteder , R. M. Ballew , Elizabeth A. Brown , J. N. Demas , D. Nesselrodt and B. A. DeGraff J. Chem. Educ., 1990, 67 (12), p 1065 {{DOI|10.1021/ed067p1065}}</ref><ref>''Halide (Cl-) Quenching of Quinine Sulfate Fluorescence: A Time-Resolved Fluorescence Experiment for Physical Chemistry'' Jonathan H. Gutow J. Chem. Educ., 2005, 82 (2), p 302 {{DOI|10.1021/ed082p302}}</ref>。

淬灭被用于制造{{le|光极|optode}}传感器，例如氧对某些[[钌]]配合物的淬灭效应可以用于测量[[溶液]]中的氧饱和度；淬灭是[[荧光共振能量转移]]（FRET）分析技术的基础<ref>{{cite book | vauthors = Peng X, Draney DR, Volcheck WM |chapter=Quenched near-infrared fluorescent peptide substrate for HIV-1 protease assay |title=Optical Molecular Probes for Biomedical Applications | veditors = Achilefu S, Bornhop DJ, Raghavachari R |year=2006 |volume=6097|pages=60970F |doi=10.1117/12.669174 |s2cid=98507102 }}</ref><ref>{{cite journal | vauthors = Peng X, Chen H, Draney DR, Volcheck W, Schutz-Geschwender A, Olive DM | title = A nonfluorescent, broad-range quencher dye for Förster resonance energy transfer assays | journal = Analytical Biochemistry | volume = 388 | issue = 2 | pages = 220–8 | date = May 2009 | pmid = 19248753 | doi = 10.1016/j.ab.2009.02.024 }}</ref><ref>{{cite journal | vauthors = Osterman H | title = The Next Step in Near Infrared Fluorescence: IRDye QC-1 Dark Quencher. | journal = Review Article | date = 2009 | volume = 388 | pages = 1–8 | url = https://www.licor.com/documents/nom6ali3zsgp4vooqhltaftp06so1kzm | archive-url =https://web.archive.org/web/20200320064315/https://www.licor.com/documents/nom6ali3zsgp4vooqhltaftp06so1kzm | archive-date= 20 March 2020 }}</ref>；特定[[靶向治疗|标靶分子]]结合时的淬灭与去淬灭效应可用作光学[[造影剂]] <ref>{{cite journal | vauthors = Blum G, Weimer RM, Edgington LE, Adams W, Bogyo M | title = Comparative assessment of substrates and activity based probes as tools for non-invasive optical imaging of cysteine protease activity | journal = PLOS ONE | volume = 4 | issue = 7 | pages = e6374 | date = July 2009 | pmid = 19636372 | pmc = 2712068 | doi = 10.1371/journal.pone.0006374 | bibcode = 2009PLoSO...4.6374B | doi-access = free }}</ref><ref>{{cite journal | vauthors = Weissleder R, Tung CH, Mahmood U, Bogdanov A | title = In vivo imaging of tumors with protease-activated near-infrared fluorescent probes | url = https://archive.org/details/sim_nature-biotechnology_1999-04_17_4/page/375 | journal = Nature Biotechnology | volume = 17 | issue = 4 | pages = 375–8 | date = April 1999 | pmid = 10207887 | doi = 10.1038/7933 | s2cid = 12362848 }}</ref>；许多[[染料]]有自淬灭现象，导致[[荧光显微镜]]的蛋白质-染料偶联物的亮度降低<ref>{{cite journal | vauthors = Jacobsen MT, Fairhead M, Fogelstrand P, Howarth M | title = Amine Landscaping to Maximize Protein-Dye Fluorescence and Ultrastable Protein-Ligand Interaction | journal = Cell Chem Biol | volume = 24 | issue = 8 | pages = 1040–1047 | date = August 2017 | pmid = 28757182 | doi = 10.1016/j.chembiol.2017.06.015 | pmc = 5563079 | doi-access = free }}</ref>；或是用作检测[[蛋白酶解]]传感器<ref>{{cite journal | vauthors = Voss EW Jr, Workman CJ, Mummert ME | title = Detection of protease activity using a fluorescence-enhancement globular substrate | journal = BioTechniques | volume = 20 | issue = 2 | pages = 286–291 | date = February 1996 | pmid = 8825159 | doi = 10.2144/96202rr06 }}</ref>。

== 淬灭机理 ==
[[Image:Fig1.gif|thumb|供体发射和受体吸收的光谱产生重叠]]

=== 荧光共振能量转移 ===
{{main|荧光共振能量转移}}
荧光淬灭可以用多种机制解释，其中的FRET是动态淬灭机制，供体与受体通过非辐射的方式转移能量。因为能量转移的过程基于二者的跃迁偶极间的[[电偶极矩|经典偶极-偶极相互作用]]，因此极其依赖于供体-受体间的距离'''''R'''''，以E∝1/'''''R'''''<sup>6</sup>的效率下降<ref>{{cite web |last=Moens |first=Pierre |name-list-style=vanc |title=Fluorescence Resonance Energy Transfer spectroscopy |url=http://www.anatomy.usyd.edu.au/mru/fret/abot.html#frete |access-date=July 14, 2012 |archive-date=2016-07-26 |archive-url=https://web.archive.org/web/20160726180607/http://www.anatomy.usyd.edu.au/mru/fret/abot.html#frete }}</ref>，通常FRET过程在100 Å的距离内发生。FRET的过程还取决于供体-受体的重叠（如图）以及跃迁偶极矩的相对取向。

=== 德克斯特电子转移 ===
{{main|德克斯特电子转移}}
{{tsl|en|Dexter electron transfer|德克斯特电子转移}}（或称为德克斯特电子交换、碰撞能量转移等）是另一种动态淬灭机制<ref>{{GoldBookRef|file=D01654|title=Dexter excitation transfer (electron exchange excitation transfer)}}</ref>，同样此过程依赖于供体和受体间的距离，能量转移速率由下式所示，此过程通常在10 Å的距离内发生<ref>{{cite web|title=Dexter Energy Transfer|url=http://chemwiki.ucdavis.edu/Theoretical_Chemistry/Fundamentals/Dexter_Energy_Transfer|website=chemwiki.ucdavis.edu|date=2 October 2013|accessdate=8 July 2014|archive-date=2014-07-14|archive-url=https://web.archive.org/web/20140714175409/http://chemwiki.ucdavis.edu/Theoretical_Chemistry/Fundamentals/Dexter_Energy_Transfer}}</ref>，式中<math>r</math>是供体与受体间的距离，<math>L</math>与<math>P</math>是不易由实验得到的常量，<math>J</math>是重叠光谱的积分<ref name=det1>{{GoldBookRef |title=Dexter excitation transfer (electron exchange excitation transfer) |file=D01654 }}</ref>。
:<math>k_{ET} \varpropto P^2 J \mathrm{exp}\left [ \frac{-2r}{L} \right ] </math>

=== 激基配合物 ===
{{main|激基缔合物}}
激发态配合物的形成过程是第三种动态淬灭过程。
[[Image:Dark quenching mechanisms.svg|thumb|静态与动态淬灭机理的比较]]

=== 静态淬灭 ===
剩余的能量转移机理是静态淬灭，静态淬灭发生在基态的荧光分子与淬灭剂通过结合形成配合物时，即激发发生之前。静态淬灭形成的配合物会失去荧光性。

=== 碰撞淬灭 ===
激发态的荧光基团与淬灭剂原子或分子碰撞时，以无辐射跃迁的方式回到基态，此种淬灭过程称为碰撞淬灭。

== 参考文献 ==
{{reflist}}

[[Category:荧光]]
[[Category:反应机理]]