Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, University of Alcalá, Alcalá de Henares, Madrid 28871, Spain.
University Institute of Research in Police Sciences (IUICP), Law Faculty, University of Alcalá, Alcalá de Henares, Madrid 28871, Spain.
Sensors (Basel). 2018 Jul 8;18(7):2196. doi: 10.3390/s18072196.
Raman spectroscopy is a selective detection system scarcely applied for the flow analysis of solutions with the aim of detecting several compounds at once without a previous separation step. This work explores the potential of a portable Raman system in a flow system for the selective detection of a mixture of seven oxyanions (carbonate, sulphate, nitrate, phosphate, chlorate, perchlorate, and thiosulphate). The specific bands of these compounds (symmetric stretching Raman active vibrations of carbonate at 1068 cm, nitrate at 1049 cm, thiosulphate at 998 cm, phosphate at 989 cm, sulphate at 982 cm, perchlorate at 935 cm, and chlorate at 932 cm) enabled their simultaneous detection in mixtures. Although the oxyanions’ limit of detection (LOD) was rather poor (in the millimolar range), this extremely simple system is very useful for the single-measurement detection of most of the oxyanions in mixtures, without requiring a previous separation step. In addition, quantitative determination of the desired oxyanion can be performed by means of the corresponding calibration line. These are important advantages for controlling in-line processes in industries like those manufacturing fertilizers, pharmaceuticals, chemicals, or food, among others.
拉曼光谱是一种选择性检测系统，很少应用于溶液的流动分析，旨在无需预先分离步骤即可同时检测多种化合物。本工作探讨了便携式拉曼系统在流动系统中用于选择性检测七种含氧阴离子（碳酸盐、硫酸盐、硝酸盐、磷酸盐、氯酸盐、高氯酸盐和硫代硫酸盐）混合物的潜力。这些化合物的特征谱带（碳酸盐在 1068 cm 处的对称伸缩拉曼活性振动、硝酸盐在 1049 cm 处、硫代硫酸盐在 998 cm 处、磷酸盐在 989 cm 处、硫酸盐在 982 cm 处、高氯酸盐在 935 cm 处和氯酸盐在 932 cm 处）使它们能够在混合物中同时检测。尽管含氧阴离子的检出限（LOD）相当差（在毫摩尔范围内），但这种极其简单的系统非常适用于混合物中大多数含氧阴离子的单次测量检测，无需预先分离步骤。此外，通过相应的校准线可以对所需含氧阴离子进行定量测定。这些对于控制肥料、制药、化工、食品等行业的在线过程非常重要。
