Calculating the Limits of Detection in Laser-Induced Breakdown Spectroscopy: Not as Easy as It Might Seem

Abstract

The objectives of this paper will be to discuss the issues related to the determination of the limits of detection (LOD) in laser-induced breakdown spectroscopy (LIBS) analytical applications. The derivation of the commonly used ‘3-sigma over slope’ rule and its evolution towards the new official definition recently adopted by the International Union of Pure and Applied Chemistry (IUPAC) will be illustrated. Methods for extending the calculation of the LOD to LIBS multivariate analysis will also be discussed, using as an example the detection of Cu traces in cast iron samples by LIBS.

Improving the Laser-Induced Breakdown Spectroscopy for Highly Efficient Trace Measurement of Hazardous Components in Waste Oils

“…LOD, regarded as one of the key parameters in LIBS quantitative analysis, is the lowest quantity of a target element that can be detected, which was calculated based on the 3σ b -IUPAC definition normalL normalO normalD = 3.3 [ ∑ ( I i − I i * ) 2 / N ] 1 + C̅ 2 / prefix∑ false( C i − C̅ false) 2 / S where N represents the number of points in the calibration curves, S represents the slope of the calibration curve, C i are the concentrations of the standards, C̅ is the average of the concentrations, I i are the intensities at the concentration, and I i * are the predicted values by the calibration curve at that concentration. The LODs of the Ba and Ca elements in different cases are listed in Table .…”

Atomic spectrometry update: review of advances in atomic spectrometry and related techniques

“…Reviews that cover detailed LIBS applications in imaging, classication, or quantitative analysis of different kinds of samples can be found elsewhere. Recent advances and future perspectives of LIBS imaging for material and biomedical applications were discussed by Gardette et al, 90 while novel methodologies and technological developments were summarised by Thomas et al 91 A tutorial describing in detail how to statistically compare predictive models for LIBS quantitative analysis and classication was published by Duponchel et al 92 Recent trends in sample classication using LIBS, providing a comprehensive introduction and overview of the steps to go from recorded data to a well-performing classier, was reviewed by Brunnbauer et al 93 The development of calibration-free LIBS (CF-LIBS) to improve accuracy in different applications was critically reviewed by Hermann et al 94 and Poggialini et al 95 In 2023 there were several international conferences dedicated to discuss the recent progress in LIBS, such as the 5th Asian Symposium on LIBS held in Tokushima (Japan) from June 26th to June 30th (https://j-libs.org/CSI2023_ASLIBS2023/ index.html), and the 12th Euro-Mediterranean Symposium on LIBS (EMSLIBS) held in Porto (Portugal) from September 4th to 7th (https://emslibs2023.inesctec.pt/).…”

“…The determination of the LODs is not considered an easy task for LIBS analytical applications. Progress towards the new official definition of LOD, recently adopted by IUPAC, and methods to extend its calculation in LIBS multivariate analysis were discussed by Poggialini et al 122 A statistical definition of LOD was proposed for CF-LIBS by Villas-Boas and Borduchi 123 based on the density of emitters, plasma parameters and measurement uncertainties. The method was validated using C and Ca in sodium chloride samples.…”

Double-enhanced LIBS system with N2 atmosphere and cylindrical cavity confinement for quantitative analysis of Sr element in soil

“…The quantitative analysis results obtained from the internal standard analytical model yielded the parameter K as the slope of the analytical model. International union of pure and applied chemistry (IUPAC) has now revised the definition of LOD, and the new definition of LOD [27] is as follows:…”