Determination of Nitrogen in Sand Using Laser-Induced Breakdown Spectroscopy

Abstract

The use of laser-induced breakdown spectroscopy (LIBS) to detect a variety of elements in soils has been demonstrated and instruments have been developed to facilitate these measurements. The ability to determine nitrogen in soil is also important for applications ranging from precision farming to space exploration. For terrestrial use, the ideal situation is for measurements to be conducted in the ambient air, thereby simplifying equipment requirements and speeding the analysis. The high concentration of nitrogen in air, however, is a complicating factor for soil nitrogen measurements. Here we present the results of a study of LIBS detection of nitrogen in sand at atmospheric and reduced pressures to evaluate the method for future applications. Results presented include a survey of the nitrogen spectrum to determine strong N emission lines and determination of measurement precision and a detection limit for N in sand (0.8% by weight). Our findings are significantly different from those of a similar study recently published regarding the detection of nitrogen in soil.

Laser Induced Breakdown Spectroscopy

“…However, the utilization of an internal standard and other alternative calibration methods has ameliorated this matter. Water [217][218][219][220][221][222] and soil [223][224][225][226][227][228][229][230][231][232][233] analyses have produced most of the papers found in the literature.…”

“…Harris et al 232 determined nitrogen in sand. Sand was employed as a substitute for soil to minimize spectral interferences and in order to compare the results with those previously obtained for soil analyses.…”

Emerging technologies for in situ measurement of soil carbon

“…Instrumentation using laser-optics, specifically laser-induced breakdown spectroscopy (LIBS), has been used in recent years for determination of a variety of soil constituents including metal ions (Yamamoto et al 1996;Bublitz et al 2001;Mosier-Boss et al 2002), nitrogen (Harris et al 2004), and total soil C (Cremers et al 2001;Ebinger et al 2003). Application of LIBS technology to soil science is appealing due to this method's sensitivity and selectivity and capability for in situ, multicomponent soil analysis with minimum sample preparation.…”

Cropland Field Monitoring: MMV Page 1 Montana Cropland Enrolled Farm Fields Carbon Sequestration Field Sampling, Measurement, Monitoring, and Verification: Application of Visible-Near Infrared Diffuse Reflectance Spectroscopy (VNIR) and Laser-induced Breakdown Spectroscopy (LIBS)

“…More specifically, matrix effects are related to the elemental and molecular composition of the sample, plasma composition, within plasma interactions, and laser-sample coupling efficiency. Previously published studies have attempted to compensate for these matrix effects and increase predictive accuracy by employing a variety of approaches (Clegg et al, 2009): (a) peak height or peak area calibration to standards with known composition (Ebinger et al, 2003;Eppler et al, 1996;Martin et al, 2003;Salle et al, 2006); (b) normalization of LIBS spectra to total emission intensity (Clegg et al, 2009;Thompson et al, 2006); (c) normalization of peak height or area to another spectral feature (Cremers et al, 2001;Eppler et al, 1996;Salle et al, 2006); (d) employing a plasma physics model without the use of calibration curves or "calibration-free LIBS" (Salle et al, 2006;Yaroshchyk et al, 2006); (e) spectrally averaging multiple interrogations per sample for calibration and and/or validation (Bousquet et al, 2007;Bousquet et al, 2008;Clegg et al, 2009;Eppler et al, 1996;Martin et al, 2003), and (f) employing chemmometric statistical approaches for predictive model calibration (Bousquet et al, 2007;Clegg et al, 2009;Ferreira et al, 2008;Martin et al, 2005;Martin et al, 2010;Martin et al, 2007;Sirven et al, 2006) With proper calibration, LIBS can provide a precise and selective method for measuring metal ions such as lead (Pb), beryllium (Be), chromium (Cr), and strontium (Sr) in paint and soils (Sirven et al, 2006;Yamamoto et al, 1996), N, Pb, and Ba in sand (Eppler et al, 1996;Harris et al, 2004), and copper (Cu), zinc (Zn), and arsenic (As) in wood preservatives (Martin et al, 2005). Though there have been relatively few applications of LIBS for soil car...…”