Sensitive determinations of Cu, Pb, Cd, and Cr elements in aqueous solutions using chemical replacement combined with surface-enhanced laser-induced breakdown spectroscopy

Abstract

In this study, chemical replacement combined with surface-enhanced laser-induced breakdown spectroscopy (CR-SENLIBS) was for the first time applied to improve the detection sensitivities of trace heavy metal elements in aqueous solutions. Utilizing chemical replacement effect, heavy metal ions in aqueous solution were enriched on the magnesium alloy surface as a solid replacement layer through reacting with the high chemical activity metallic magnesium (Mg) within 1 minute. Unitary and mixed solutions with Cu, Pb, Cd, and Cr elements were prepared to construct calibration curves, respectively. The CR-SENLIBS showed a much better detection sensitivity and accuracy for both unitary and mixed solutions. The coefficients of determination R² of the calibration curves were above 0.96, and the LoDs were of the same order of magnitude, i.e., in the range of 0.016-0.386 μg/mL for the unitary solution, and in the range of 0.025-0.420 μg/mL for the mixed solution. These results show that CR-SENLIBS is a feasible method for improving the detection sensitivity of trace element in liquid sample, which definitely provides a way for wider application of LIBS in water quality monitoring.

Laser Spectroscopic Sensors for the Development of Anthropomorphic Robot Sensitivity

“…However, special pre-processing technology was used in this research work. For Cu, better LoDs were obtained in [ 29 , 30 ], but in this case the plasma was formed in a liquid jet (HCl solution) by emission from an ArF laser with wavelength 193 nm.…”

Improving the Detection Sensitivity for Laser-Induced Breakdown Spectroscopy: A Review

“…Compared with the filter paper method, the LODs of these elements increased by 2-4 times. They also detected some metallic elements in the solution using chemical replacement combined with SENLIBS, and the minimum detection limits were 0.250 g.ml −1 (Cu), 0.118 g.ml −1 (Pb), 0.420 g.ml −1 (Cd) and 0.025 g.ml −1 (Cr), respectively [34].…”

“…Some of these methods improve the LIBS signal intensity by changing the LIBS setup, such as adding a second laser pulse for secondary heating of the plasma [26][27][28][29][30]. In other methods, the sensitivity is improved by chemical treatment of the sample, such as chemical replacement to preconcentrate the element of interest in the sample [31][32][33][34]. Furthermore, mathematical methods, such as multivariate analysis instead of univariate analysis [35,36], can be used to improve the sensitivity of the predictive model.…”

Laser Induced-Breakdown Spectroscopy (Libs): Histórico, Fundamentos, Aplicações E Potencialidades

“…56 Em trabalho proposto por Lee et al 57 os autores utilizaram uma bomba peristáltica para produzir um "jato" da amostra, no qual o pulso de laser foi irradiado diretamente. Outras estratégias envolvem a transferência da amostra líquida para substratos não permeáveis como grafite 58 e placa de metal, 59 ou para substratos permeáveis como o papel filtro. 60 Nesses casos, a amostra líquida é depositada nesses substratos e, após secagem do material o substrato é analisado.…”