Sensitive analysis of trace water analytes using colourimetric cavity ringdown spectroscopy
Sensitive analysis of trace water analytes using colourimetric cavity ringdown spectroscopy
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DOI：
10.1039/c2ay25889g
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发表时间：
2013-01-01
影响因子：
3.1
通讯作者：
Vallance, Claire
中科院分区：
文献类型：
--
作者：
Rushworth, Cathy M.;Yogarajah, Yathukulan;Vallance, Claire
应用比色腔衰荡光谱技术，以亚硝酸根和铁（II）为被测物，研究了水中痕量化合物的检测。将样品包含在三个市售流通池中的一个内，流通池的光程长度范围为0.1 mm至2.0 mm，并定位在双镜衰荡腔内。引入腔中的光脉冲的强度的衰减率的测量允许样品的光吸收的超灵敏测定。首先进行使用高锰酸钾在532 nm处的已知吸收系数的校准，以确定在使用每个流动池时每单位路径长度的最小可检测吸收方面的检测灵敏度。亚硝酸盐和铁的检测，然后进行使用众所周知的颜色反应，即Griess反应的亚硝酸盐和红菲咯啉方法的铁（II），转化为强吸收的衍生物，这是量化的分析物的空腔衰荡测量。在这第一个应用的比色腔衰荡光谱的液相中，亚硝酸盐和3.8 nM的Fe（II）的检测限为1.9 nM的路径长度为1.0 mm的流通池中被证明。分析的样品的体积仅为196 nL，因此，该顺序的检测限对应于检测不到10亿个分子。因此，该检测方法适合于集成到微流体感测平台中。
The application of colourimetric cavity ringdown spectroscopy to the detection of trace compounds in water has been investigated using nitrite and iron(II) as test analytes. Samples were contained within one of three commercially available flow cells ranging in optical path length from 0.1 mm to 2.0 mm, and positioned within a two-mirror ringdown cavity. A measurement of the decay rate of the intensity of an optical pulse introduced into the cavity allows an ultrasensitive determination of optical absorption by the sample. A calibration using the known absorption coefficient of potassium permanganate at 532 nm was first carried out in order to determine the detection sensitivity in terms of minimum detectable absorption per unit path length when using each flow cell. The detection of nitrite and iron was then carried out by using well-known colour reactions, namely the Griess reaction for nitrite and the bathophenanthroline method for iron(II), to convert the analytes into strongly absorbing derivatives, which were quantified by a cavity ringdown measurement. In this first application of colourimetric cavity ringdown spectroscopy to the liquid phase, detection limits of 1.9 nM for nitrite and 3.8 nM for Fe(II) were demonstrated in a flow cell of path length 1.0 mm. The volume of sample analysed is only 196 nL, so that detection limits of this order correspond to the detection of less than 1 billion molecules. The detection method is therefore suitable for integration into a microfluidic sensing platform.