一二三四区视频,亚洲少妇熟女色,日本久热无码视频网,欧美国产日韩大尺度,亚洲a视频,久久少妇一区二区,日韩999无码视频,刺激久久久久久久,啊啊啊啊不要啊在线

ChemicalBook >> journal list >> Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy >>article

Absorption and fluorescence properties of fluorescein

Published:1 June 1995 DOI: 10.1016/0584-8539(95)01421-P
Robert Sj?back , Jan Nygren , Mikael Kubista

Abstract

We have characterized the protolytic equilibria of fluorescein and determined the spectroscopic properties of its protolytic forms. The protolytic constants relating the chemical activities (which at low ionic strength equal concentrations) of the cation, neutral form, anion and dianion are pK1 = 2.08, pK2 = 4.31, and pK3 = 6.43. All forms have rather high molar absorptivities being ε437FH31 = 53 000, ε434FH2 = 11 000, ε453FH? = 29 000 (ε472FH = 29 000) and ε490F2 = 76 900 M?1 cm?1 for the cation, neutral form, anion and dianion, respectively. The dianion has the most intense fluorescence with a quantum yield of 0.93 but also the anion shows considerable fluorescence with a quantum yield of 0.37. The neutral and cationic species are upon excitation converted into the anion and fluoresce with quantum yields of about 0.30 and 0.18, respectively.

Substances (1)

Related products
Procduct Name CAS Molecular Formula Supplier Price
Fluorescein 2321-07-5 C20H12O5 473 suppliers $6.00-$1785.00

Similar articles

IF:3.3

The pH dependence of fluorescein fluorescence

Journal of Luminescence Monique M. Martin, Lars Lindqvist,etc Published: 1 July 1975
IF:0.6

Fluorescence in a cryptococcoma following administration of 5-aminolevulinic acid hydrochloride (Gliolan).

BMJ Case Reports Waldo Gerard Solis, Mitchell Hansen,etc Published: 11 April 2017
IF:0.5

Investigations of carbon dioxide absorption into aqueous potassium carbonate solutions containing primary and secondary alkanolamines

Chemical and Process Engineering-Inzynieria Chemiczna I Procesowa G. Binczak,?W. Moniuk,etc Published: 1 March 2016
鞍山市| 栾川县| 曲松县| 萍乡市| 六枝特区| 丰原市| 黄平县| 武穴市| 巢湖市| 南陵县| 鄂托克旗| 文登市| 宝坻区| 昌乐县| 离岛区| 古田县| 洞口县| 商洛市| 苏尼特左旗| 西平县| 台东县| 阿拉善盟| 聊城市| 上思县| 太白县| 密云县| 周宁县| 保靖县| 泌阳县| 商水县| 清苑县| 安徽省| 武川县| 印江| 洪雅县| 吉安市| 北宁市| 垫江县| 宝山区| 晋宁县| 肥西县|