利用三维荧光结合平行因子算法研究金属离子对溶解性有机物的猝灭和校正

摘要

溶解性有机物的荧光组份由于受到金属离子的影响其荧光强度受到变化,从而为溶解性有机物的定量分析带来挑战.利用三维荧光结合平行因子分析方法研究了Cu(Ⅱ),Fe(Ⅲ),Ni(Ⅱ),Sr(Ⅱ),Hg(Ⅱ),K(Ⅰ),Mg(Ⅱ) 和Mn(Ⅱ)八个金属离子对典型溶解性有机物荧光组分的荧光猝灭作用,五个水样来源各不相同.实验表明水样被平行因子成功分解为三个荧光组分(色氨酸、腐殖酸、富里酸),这三个荧光组份的荧光得分随着Fe(Ⅲ),Cu(Ⅱ),Hg (Ⅱ)和 Ni(Ⅱ)浓度的增加呈线性或指数下降.在这四种离子中,Fe(Ⅲ)和Cu(Ⅱ)对腐殖酸和富里酸的荧光猝灭作用明显大于Hg (Ⅱ)和 Ni(Ⅱ).Sr(Ⅱ),K(Ⅰ),Mg(Ⅱ)和Mn(Ⅱ)基本没有影响.其中Fe(Ⅲ)对于三个荧光组分的荧光猝灭都有较好的分析.由于只考虑Fe(Ⅲ) 和Cu(Ⅱ)的影响,对于含有金属离子的饮用水的荧光强度的校正曲线也被建立.不同来源的饮用水中荧光组份的荧光得分的衰减规律也是不一样的,因此水样的来源也是测量时需要考虑的因素.实验证实了金属离子对溶解性有机物的荧光猝灭作用以及其他因素比如Fe(Ⅲ) 和Cu(Ⅱ)和溶解性有机物本身的多样性都是我们荧光测量典型荧光组份时需要考虑的.表明三维荧光结合平行因子分析方法是一个有效的准确测量溶解性有机物荧光组份的工具.%There are several challenges with quantitative analysis of fluorescence components of dissolved or-ganic matter (DOM ) stem from the variability of fluorescence intensity ,which is known to be highly influenced by metal ions .The quenching effect of metal ions (Cu(Ⅱ) ,Fe(Ⅲ) ,Ni(Ⅱ) ,Sr(Ⅱ) ,Hg(Ⅱ) ,K(Ⅰ ) ,Mg (Ⅱ) and Mn(Ⅱ)) on the typical components of DOM in drinking water was explored using fluorescence exci-tation-emission matrix (EEM ) or fluorescence excitation-emission matrix and parallel factor analysis (EEM-PARAFAC) .Drinking water samples were collected from various sources .Results show three components (tryptophan-like ,fulvic-like ,and humic-like) ,which were identified in the DOM of drinking water samples by parallel factor analysis (PARAFAC) ,exhibit a linear or an exponential PARAFAC scores decrease with con-centration of four metal ions (Fe(Ⅲ) ,Cu(Ⅱ) ,Hg (Ⅱ) and Ni(Ⅱ))increasing .Among these four metal ions ,Fe(Ⅲ) and Cu(Ⅱ) led to a stronger quenching effect on fulvic-like and humic-like than Hg(Ⅱ) and Ni(Ⅱ ) .Sr(Ⅱ) ,K(Ⅰ) ,Mg(Ⅱ) and Mn(Ⅱ) had almost no effect on three components .Fe(Ⅲ) have good effects to characterize metal ions fluorescence quenching on all PARAFAC-derived components of DOM .Owing to we only consider the effect of Cu(Ⅱ) and Fe(Ⅲ) when we need quantificational measure fulvic-like and humic-like components in drinking water ,calibration curves were set up to correct fluorescence data in drinking water containing metal ions .Thus ,we can obtain the original fluorescence data in drinking water containing metal i-ons .Owing to different sources of PARAFAC-derived components scoring attenuation laws are various ,the sources of drinking water is also a factor that must be considered when measuring the fluorescent components using the PARAFAC model .The results from this study confirmed the interference of metal ions on the fluo-rescence intensity of the main components of DOM in drinking water and the factors (Fe(Ⅲ) ,Cu(Ⅱ) and var-iability of DOM ) need to be considered when measuring the typical components of DOM in drinking water with EEM .This study indicated that the application of EEM-PARAFAC in fluorescence quenching studies is a use-ful tool to accurately measure fluorescence components of DOM in drinking water .