Raman spectroscopic sensors for inorganic salts

Fontana, M.D.; Mabrouk, K. Ben; Kauffmann, Thomas

doi:10.1039/9781849737791-00040

Cited by 32 publications

(25 citation statements)

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“…Due to the symmetric profile of the v 1 (SO 4 2− ) mode is independent of salt concentration and the strong the v 1 (SO 4 2− ) mode in aqueous solutions, qualitative identification of the concentration can be achieved by the MGSHRS. The quantification needs two processes [18]: the intensity of the Raman signature peak is integrated over the whole wavenumber region 940 to 1020 cm −1 covered by the v 1 (SO 4 2− ) mode, which includes the whole intensity under the peak, including the background; After the normalization and derived by the intensity of peak maximum in order to avoid a change due to any change external parameter in experimental conditions, such as the temperature, laser beam intensity. In our case, the regression coefficient r 2 = 0.985 is obtained, proven to be an efficient and appropriate to determine the concentration of sodium sulfate (Na 2 SO 4 ), potassium sulfate (K 2 SO 4 ) and ammonium sulfate ((NH 4 ) 2 SO 4 ) in water using our Raman spectrometer.…”

Section: Raman Analysis Of Sulfates In Aqueous Solutionmentioning

confidence: 99%

Raman Spectroscopic Investigation of Sulfates Using Mosaic Grating Spatial Heterodyne Raman Spectrometer

Qiu

2019

IEEE Photonics J.

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We introduce a field-widened spatial heterodyne Raman spectrometer with a mosaic grating structure to investigate the broadband Raman spectra of sulfates. The broadband static spatial heterodyne Raman spectrometer configuration employs two mosaic gratings instead of the diffraction gratings to divide the broadband Raman spectrum into two bands. It is able to record high-resolution, broadband Raman spectrum range, covering 5740 cm −1 with 3.061 cm −1 spectral resolution using a regular CCD in a single-shot measurement. Raman spectra of mineral sulfates (celestine, gypsum) are investigated. This is the first time to conduct this Raman spectroscopic experiments to investigate the sulfates using the spatial heterodyne Raman spectroscopy. The sodium, potassium and ammonium sulfates at solid state and in aqueous solutions had been detected and analyzed. The effects of metal ions (K + , Na + , NH 4 + , Ca 2+ , Sr 2+) on vibration of sulfate anion SO 4 2− were discussed. The main v 1 mode can be probed by the spatial heterodyne Raman spectroscopy to determine the concentration of sulfate and unambiguous identification of different sulfate minerals, solid sulfates.

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Section: Raman Analysis Of Sulfates In Aqueous Solutionmentioning

confidence: 99%

Raman Spectroscopic Investigation of Sulfates Using Mosaic Grating Spatial Heterodyne Raman Spectrometer

Qiu

2019

IEEE Photonics J.

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“…Raman spectra of the phosphate-buffered M9 medium (47 mM monobasic and 22 mM dibasic potassium phosphate), water, and the empty tube as references are shown in Fig. 3a [36]. Peak C is the bending vibration of the water solvent at 1630 cm −1 .…”

Section: Methodsmentioning

confidence: 99%

On-line analysis and in situ pH monitoring of mixed acid fermentation by Escherichia coli using combined FTIR and Raman techniques

2020

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We introduce an experimental setup allowing continuous monitoring of bacterial fermentation processes by simultaneous optical density (OD) measurements, long-path FTIR headspace monitoring of CO2, acetaldehyde and ethanol, and liquid Raman spectroscopy of acetate, formate, and phosphate anions, without sampling. We discuss which spectral features are best suited for detection, and how to obtain partial pressures and concentrations by integrations and least squares fitting of spectral features. Noise equivalent detection limits are about 2.6 mM for acetate and 3.6 mM for formate at 5 min integration time, improving to 0.75 mM for acetate and 1.0 mM for formate at 1 h integration. The analytical range extends to at least 1 M with a standard deviation of percentage error of about 8%. The measurement of the anions of the phosphate buffer allows the spectroscopic, in situ determination of the pH of the bacterial suspension via a modified Henderson-Hasselbalch equation in the 6–8 pH range with an accuracy better than 0.1. The 4 m White cell FTIR measurements provide noise equivalent detection limits of 0.21 μbar for acetaldehyde and 0.26 μbar for ethanol in the gas phase, corresponding to 3.2 μM acetaldehyde and 22 μM ethanol in solution, using Henry’s law. The analytical dynamic range exceeds 1 mbar ethanol corresponding to 85 mM in solution. As an application example, the mixed acid fermentation of Escherichia coli is studied. The production of CO2, ethanol, acetaldehyde, acids such as formate and acetate, and the changes in pH are discussed in the context of the mixed acid fermentation pathways. Formate decomposition into CO2 and H2 is found to be governed by a zeroth-order kinetic rate law, showing that adding exogenous formate to a bioreactor with E. coli is expected to have no beneficial effect on the rate of formate decomposition and biohydrogen production.

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“…The vibrational modes of H 2 PO 4 − in solution are located respectively at 886 (ν 1 ), 356 (ν 2 ), 1,085 (ν 3 ), and 495 cm −1 (ν 4 ) …”

Section: Raman Data and Lines Assignmentmentioning

confidence: 99%

Raman spectra in LiH₂PO₄ and KLi(H₂PO₄)₂: Mode assignment

Dekhili

Kauffmann

Aroui

et al. 2018

J Raman Spectroscopy

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We report and analyze Raman spectra recorded on crystals of LiH 2 PO 4 (LDP) and KLi(H 2 PO 4 ) 2 (KLDP). We provide a new and complete assignment of Raman lines in both crystals from their behavior as function of temperature. Among internal vibrations, we discern the modes within PO 4 tetrahedra, the modes related to Li-O bonds, and those due to the O-H vibrations. In the wavenumber range between 300 and 600 cm −1 , the lines associated with O-P-O or Li-O show different temperature dependencies. The bands of PO 4 are red-shifted with increasing temperature according to thermal dilatation, whereas the positions related to Li-O are temperature independent.

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Raman spectroscopic sensors for inorganic salts

Cited by 32 publications

References 1 publication

Raman Spectroscopic Investigation of Sulfates Using Mosaic Grating Spatial Heterodyne Raman Spectrometer

Raman Spectroscopic Investigation of Sulfates Using Mosaic Grating Spatial Heterodyne Raman Spectrometer

On-line analysis and in situ pH monitoring of mixed acid fermentation by Escherichia coli using combined FTIR and Raman techniques

Raman spectra in LiH₂PO₄ and KLi(H₂PO₄)₂: Mode assignment

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Raman spectroscopic sensors for inorganic salts

Cited by 32 publications

References 1 publication

Raman Spectroscopic Investigation of Sulfates Using Mosaic Grating Spatial Heterodyne Raman Spectrometer

Raman Spectroscopic Investigation of Sulfates Using Mosaic Grating Spatial Heterodyne Raman Spectrometer

On-line analysis and in situ pH monitoring of mixed acid fermentation by Escherichia coli using combined FTIR and Raman techniques

Raman spectra in LiH2PO4 and KLi(H2PO4)2: Mode assignment

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Raman spectra in LiH₂PO₄ and KLi(H₂PO₄)₂: Mode assignment