Raman Spectroscopy of Symmetric Oxyanions

Comstock, Matthew; Gray, Jeffrey A.

doi:10.1021/ed076p1272

Cited by 15 publications

(13 citation statements)

References 7 publications

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“…This work particularly applies the capability of flow Raman selective analysis on the simultaneous detection of oxyanions, which are common compounds found in many industries that work with biomolecules production, enzymatic fermentation, mining residues, water and waste treatment, etc. The static Raman detection of oxyanions such as sulphate, nitrate, perchlorate, carbonate, thiosulphate, and chlorate, either as solid salts or in solutions, has been extensively reported in the literature [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. However, the simultaneous Raman detection of several oxyanions in flow solutions showed few advances along the years.…”

Section: Introductionmentioning

confidence: 99%

Selective Monitoring of Oxyanion Mixtures by a Flow System with Raman Detection

Zapata

Ortega-Ojeda

García-Ruiz

et al. 2018

Sensors

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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−1, nitrate at 1049 cm−1, thiosulphate at 998 cm−1, phosphate at 989 cm−1, sulphate at 982 cm−1, perchlorate at 935 cm−1, and chlorate at 932 cm−1) 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.

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Section: Introductionmentioning

confidence: 99%

Selective Monitoring of Oxyanion Mixtures by a Flow System with Raman Detection

Zapata

Ortega-Ojeda

García-Ruiz

et al. 2018

Sensors

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show abstract

“…Interested students can further explore oxyanions in saturated solutions of Na 2 CO 3 , Na 2 SO 3 and NaNO 3 . 4 A valuable experience for students is the analysis of the line shifts between chloroform (CHCl 3 ) and the deuterated heavy form (CDCl 3 ). Figure 3 shows the Raman spectra of both substances.…”

Section: Experiments and Resultsmentioning

confidence: 99%

Raman spectroscopy setup and experiments for the advanced undergraduate lab

Bausinger

2015

SPIE Proceedings

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Raman Spectroscopy is an important characterization technique in analytical chemistry and in solid state physics. This contribution describes the redesign of a Raman experiment for the Advanced Physics Lab and shows experimental results acquired with this new setup. Solid and liquid samples are irradiated by a frequency doubled Nd:YAG laser in backscattering geometry. The emission is focused onto the fibre end face of an USB spectrometer. Stokes and Anti-Stokes emission lines are observed simultaneously and their polarisation is analysed. The students start with the spectral calibration of the spectrometer and check its linearity. They optimize their first Raman spectrum of solid sulfur according to these results and evaluate the intensity ratio of the corresponding Stokes and Anti-Stokes lines for a temperature measurement of the sample. The students explain the spectral differences of a series of chlorine-substituted hydrocarbons by the changes in the molecular structures and symmetries. Finally they determine the concentration of an unknown water-ethanol solution. This contribution discusses also safety concerns regarding the used hydrocarbons and shows alternative samples. Raman Spectroscopy is an important characterization technique in analytical chemistry and in solid state physics. This contribution describes the redesign of a Raman experiment for the Advanced Physics Lab and shows experimental results acquired with this new setup. Solid and liquid samples are irradiated by a frequency doubled Nd:YAG laser in backscattering geometry. The emission is focused onto the fibre end face of an USB spectrometer. Stokes and Anti-Stokes emission lines are observed simultaneously and their polarisation is analysed. The students start with the spectral calibration of the spectrometer and check its linearity. They optimize their first Raman spectrum of solid sulfur according to these results and evaluate the intensity ratio of the corresponding Stokes and Anti-Stokes lines for a temperature measurement of the sample. The students explain the spectral differences of a series of chlorine-substituted hydrocarbons by the changes in the molecular structures and symmetries. Finally they determine the concentration of an unknown water-ethanol solution. This contribution discusses also safety concerns regarding the used hydrocarbons and shows alternative samples.

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“…Finally, we have used the Ocean Optics S2000 instrument to conduct Raman scattering experiments based upon a slightly modified version of the Raman experiment in the physical chemistry laboratory textbook by Shoemaker et al (15)(16)(17). In this experiment, the Raman active vibrational modes of CCl 4 and CBr 4 are investigated at room temperature.…”

Section: Spectral Datamentioning

confidence: 99%