Investigation of detection limits for solutes in water measured by laser Raman spectrometry

Abstract

The influence of experimental parameters on detection sensitivity was determined for laser Raman analysis of dissolved solutes in water. Individual solutions of nitrate, sulfate, carbonate, bicarbonate, monohydrogen phosphate, dihydrogen phosphate, acetate ion, and acetic acid were measured. An equation is derived which expresses the signal-to-noise ratio in terms of solute concentration, measurement time, spectral slit width, laser power fluctuations, and solvent background intensity. Laser beam Intensity fluctuations at the sample and solvent background intensity are the most important limiting factors.

Acid saline fluid inclusions: examples from modern and Permian extreme lake systems

“…The advent of laser Raman spectroscopy provided a method to analyze individual fluid inclusions in situ for specific covalently bonded compounds, some of which are related to pH. Aqueous sulfate and bisulfate were found to be easily distinguished by this method (Turner 1972;Cunningham et al 1977;Rosasco & Roedder 1979;Rudolph 1996). Moissette et al (1990), Dubessy et al (1992), and Boiron et al (1999) used the ratio of the areas of the Raman spectral peaks of sulfate and bisulfate to calculate very low pHs (approximately À0.5 to 2).…”

“…Aqueous sulfate and bisulfate were found to be easily distinguished by this method (Turner ; Cunningham et al . ; Rosasco & Roedder ; Rudolph ). Moissette et al .…”

Extremely acid Permian lakes and ground waters in North America

“…2). The fact that SO 2− 4 and HSO − 4 can easily be distinguished by Raman spectroscopy [11][12][13] means that their relative concentrations can be used to estimate pH (ref. 14).…”

“…Double-labelled ( 13 C, 15 N) glycine was used in a macrocosm study of arctic tundra, showing that plant uptake of glycine-derived nitrogen was as fast as uptake of NH + 4 , but this gave no evidence that the 13 C-labelled tracer was taken up 10 . Variations in the natural abundance of 15 N among plants in the field may be related to use of different nitrogen sources, but analysis of these variations is unlikely to yield conclusive quantitative evidence of the relative importance of organic and inorganic nitrogen uptake 11 .…”

Raman spectroscopy as polyvalent alternative for water pollution detection

“…3), there are only a few characteristic peaks for each species. Since these species www.ietdl.org were previously studied, the literature permitted the identification of their characteristic peaks [16,[40][41][42][43][44][45]. The nitrates present two peaks in the 750-2000 cm −1 zone, the main one being at 1052 cm −1 .…”