摘要
为了更好地区分测量小分子芳香烃,利用一台Nd∶YAG激光器提供能量为0.085J·cm-2、波长为266nm的入射光。针对苯、甲苯、萘、菲、蒽、芘和屈不同环数的芳香烃,使用激光诱导荧光法研究了单一芳香烃及不同芳香烃混合物的荧光光谱。结果表明,芳香烃的苯环数是荧光发射光谱的主要决定因素;相同苯环数不同结构的芳香烃对荧光光谱范围基本没有影响;由于266nm波长的吸收效率差异,导致相同环数的芳香烃的荧光光强存在差异;而且吸收效率相近且浓度相同时,环数越大,荧光光强越强。随着芳香烃环数的增加,荧光光谱波段和峰值都出现从紫外波段向可见光波段红移的现象,同时吸收效率相近时,荧光光谱范围变宽;一环至四环芳香烃的较好的荧光光谱区分范围分别为275-320,320-375,375-425和425-556nm。针对不同芳香烃混合物研究表明,由于辐射能量传递机制导致混合物中有3环或4环芳香烃存在时,紫外波段的光被损失,所以1环或2环芳香烃混入混合物后,混合物中的1环或2环荧光光谱不能被检测到,但荧光光谱强度增大;当混合物中只包含3环和4环芳香烃时,荧光发射光谱具有两种芳香烃的特点;当混合物中存在3环和4环芳香烃时,荧光发射光谱和各自的浓度相关,从而可以一定程度区分不同环数物质。
In order to distinguish small aromatics preferably,a Nd∶YAG Laser was used to supply an excitation laser,which was adjusted to 0.085J·cm-2 at 266 nm.Benzene,toluene,naphthalene,phenanthrene,anthracene,pyrene and chrysene were used as the representative of different rings aromatics.The fluorescence emission spectra were researched for each aromatic hydrocarbon and mixtures by Laser induced fluorescence（LIF）.Results showed that the rings number determined the fluorescence emission spectra,and the structure with same rings number did not affect the emission fluorescence spectrum ranges.This was due to the fact that the absorption efficiency difference at 266 nm resulted in that the fluorescence intensities of each aromatic hydrocarbon with same rings number were different and the fluorescence intensities difference were more apparently with aromatic ring number increasing.When the absorption efficiency was similar at 266 nm and the concentrations of each aromatic hydrocarbon were same,the fluorescence intensities were increased with aromatic ring number increasing.With aromatic ring number increasing,the fluorescence spectrum and emission peak wavelength were all red-shifted from ultraviolet to visible and the fluorescence spectrum range was also wider as the absorption efficiency was similar.The fluorescence emission spectra from one to four rings could be discriminated in the following wavelengths,275 to 320nm,320 to 375nm,375 to 425nm,425 to 556nm,respectively.It can be used for distinguish the type of the polycyclic aromatic hydrocarbons（PAHs）as it exists in single type.As PAHs are usually exist in a variety of different rings number at the same time,the results for each aromatic hydrocarbon may not apply to the aromatic hydrocarbon mixtures.For the aromatic hydrocarbon mixtures,results showed that the one-or two-ring PAHs in mixtures could not be detected by fluorescence as three-or four-ring PAHs existed in mixture.This was caused by radiation energy transfer mechanism,in which the ultraviolet light
出处
《光谱学与光谱分析》
SCIE
EI
CAS
CSCD
北大核心
2015年第6期1592-1596,共5页
Spectroscopy and Spectral Analysis
基金
国家自然科学基金国际(地区)合作交流项目(51320105008)资助
关键词
激光诱导荧光
光谱
多环芳香烃
苯环
Laser induced fluorescence
Spectroscopy
Polycyclic Aromatic Hydrocarbons（PAH）
Aromatic rings
