One-point Calibration Research Articles

Quantitative analysis of titanium alloys using one-point calibration laser-induced breakdown spectroscopy

The development of real-time and on-line quantitative composition analysis is desired for the products quality improvement in the metal producing and processing industries. Accuracy is still a challenge for classical calibration-free laser-induced breakdown spectroscopic (CF-LIBS) quantitative analysis due to the influence of the inaccurate plasma temperature calculations, uncertainties associated with Einstein coefficients and imprecise efficiency of spectral detection system. In this paper, we present an improving quantitative analysis for both major and minor elements in titanium alloys using the one-point calibration LIBS (OPC-LIBS) method. In OPC-LIBS, one matrix-matched standard sample of known composition was used to synchronously correct the essential experimental and spectroscopic parameters. A Saha–Boltzmann plot covering a large energy range was used to obtain more accurate plasma temperature and electron density values. From the comparison results, the OPC-LIBS method leads to a more accurate determination of the titanium alloy composition compared with the conventional CF-LIBS approach.

Quantitative elemental analysis of aluminum alloys with one-point calibration high repetition rate laser-ablation spark-induced breakdown spectroscopy

A one-point calibration method has been successfully used to improve the analytical accuracy of the calibration free HRR LA-SIBS technique.

Calibration Strategies Applied to Laser-Induced Breakdown Spectroscopy: A Critical Review of Advances and Challenges

Over the years, laser-induced breakdown spectroscopy (LIBS) has been reported in the literature as an alternative to traditional methods of analysis, becoming well established among spectroanalytical techniques. LIBS is a technique widely used for qualitative approaches; however, it is necessary considerable effort for use in quantitative analysis, mainly due to severe matrix effects. These limitations make it difficult to broaden the application of LIBS in quantitative analysis. In this sense, this review discusses recent advances in calibration strategies applied in LIBS for minimizing matrix effects and enabling determination with satisfactory accuracy and precision. Applications, advantages, and limitations of the calibration strategies, such as matrix-matching calibration (MMC), internal standardization (IS), standard addition (SA), multi-energy calibration (MEC), one-point gravimetric standard addition (OP GSA), one-point and multi-line calibration (OP MLC), slope ratio calibration (SRC), two-point calibration transfer (TP CT), single-sample calibration (SSC), multiple linear regression (MLR), principal component regression (PCR), partial least squares (PLS) and artificial neural networks (ANN) are discussed.

A combined flow injection/reversed-phase chromatography-high-resolution mass spectrometry workflow for accurate absolute lipid quantification with 13C internal standards.

We propose a fully automated novel workflow for lipidomics based on flow injection, followed by liquid chromatography-high-resolution mass spectrometry (FI/LC-HRMS). The workflow combined in-depth characterization of the lipidome achieved via reversed-phase LC-HRMS with absolute quantification by using a large number of lipid species-specific and/or retention time (RT)-matched/class-specific calibrants. The lipidome of 13C-labelled yeast (LILY) provided a large panel of cost-effective internal standards (ISTDs) covering triacylglycerols (TG), steryl esters (SE), free fatty acids (FA), diacylglycerols (DG), sterols (ST), ceramides (Cer), hexosyl ceramides (HexCer), phosphatidylglycerols (PG), phosphatidylethanolamines (PE), phosphatidic acids (PA), cardiolipins (CL), phosphatidylinositols (PI), phosphatidylserines (PS), phosphatidylcholines (PC), lysophosphatidylcholines (LPC) and lysophosphatidylethanolamines (LPE). The workflow in combination with the LILY lipid panel enables simultaneous quantification via (1) external multi-point calibration with internal standardization and (2) internal one-point calibration with LILY as a surrogate ISTD, increasing the coverage while keeping the accuracy and throughput high. Extensive measures on quality control allowed us to rank the calibration strategies and to automatically select the calibration strategy of the highest metrological order for the respective lipid species. Overall, the workflow enabled a streamlined analysis, with a limit of detection in the low femtomolar range, and provided validation tools together with absolute concentration values for >350 lipids in human plasma on a species level. Based on the selected standard panel, lipids from 7 classes (LPC, LPE, PC, PE, PI, DG, TG) passed stringent quality filters, which included QC accuracy, a precision and recovery bias of <30% and concentrations within the 99% confidence interval of the international laboratory comparison of SRM 1950, NIST, USA. The quantitative values are independent of common deuterated or non-endogenous ISTDs, thus offering cross-validation of different lipid methods and further standardizing lipidomics.

Evaluation method of the micro-occurrence and utilization patterns of gas via a novel method based on nuclear magnetic resonance

The micro-occurrence and utilization patterns of coalbed methane and shale gas are complex, which has limited their scientific explorations and exploitation. Based on high-temperature/high-pressure nuclear magnetic resonance (NMR) online detection technology, a T2 cut-off calibration method for adsorbed, pore-confined and free gas was established. The “one-point calibration method” for the NMR T2 cut-off value of the adsorbed gas was established by combining conventional isothermal adsorption and NMR technology, which substantially facilitated and simplified engineering applications. Based on the calibration of T2 cut-off values for different states, the variations in coalbed methane or shale gas under different occurrence states and the impact of this variation on gas production was quantitatively evaluated during production. Coalbed rock samples from the East Mabi block of the Qinshui Basin, Shanxi Province were used to study the aforementioned method. This study shows that approximately 90% of the coalbed methane is in an adsorbed state, and the proportion of adsorbed methane is slightly lower if the samples contain water. In addition, adsorbed gas is the main source of coalbed methane production, followed by pore-confined gas, with only a small contribution from free gas. Approximately 70% of the gas produced from dry coal samples comes from adsorbed gas, and approximately 60% of the gas produced from wet coal samples comes from adsorbed gas. The contribution of pore-confined gas to production is approximately 20%, regardless of the difference in the water content of the samples. At different development stages, different occurrence states vary significantly in their contribution to drainage and recovery. In the early stage, production is mainly from pore-confined gas and free gas, while in the later stage, it is mainly from adsorbed gas. As production proceeds, the output gradually increases. If pressure drops to a certain value, the output gradually decreases, and maximum production is achieved at approximately 3 MPa. This article lays the foundation for more economical and effective exploitation of coalbed methane and shale gas.

Solid-phase extraction and gas chromatography-mass spectrometry analysis of 11-nor-9-carboxy-δ9-tetrahydrocannabinol in urine for monitoring marijuana abuse

A specimen pretreatment procedure, combining solid-phase extraction and methylation, was developed for the analysis of 11-nor-9-carboxy-Δ9- tetrahydrocannabinol (9-THC-COOH) in urine for monitoring marijuana exposure. d3-11-Nor-9-carboxy-Δ9-tetrahydrocannabinol (d3-9-THC-COOH) was used as an internal standard, while the now universal selected ion monitoring gas chromatography-mass spectrometry approach was used for detection (m/z 313, 357, 372 and 316, 360, 375 for 9-THC-COOH and d3-9-THC-COOH, respectively) and quantitation (m/z 372 and 375 for 9-THC-COOH and d3-9-THC-COOH, respectively). The effectiveness of the overall procedure was evaluated. One of the extraction columns evaluated achieved > 90% recovery of the analyte in 5-mL drug-free urine fortified with 15 ng/mL 9-THC-COOH. Using the one-point calibration approach, the overall protocol achieved the following analytical parameters: detection limit: 2.09 ng/mL; limit of quantitation: 4.18 ng/mL; upper end of linear range: 376 ng/mL (or better); interday precision: 1.49- 8.03% CV in the 4.18-376 ng/mL concentration range studied.

Direct determination of Al and Pb in waste printed circuit boards (PCB) by laser-induced breakdown spectroscopy (LIBS): Evaluation of calibration strategies and economic - environmental questions

Matrix-matching calibration (MMC), two-point calibration transfer (TP CT), one-point and multi-line calibration (OP MLC), single-sample calibration (SSC) and calibration free (CF) were evaluated in order to overcome matrix effects in laser-induced breakdown spectroscopy (LIBS). These calibration strategies were evaluated for direct determination of Al and Pb in waste printed circuit boards (PCB) using direct solids analysis by LIBS. Each strategy has limitations and advantages of its implementation, for the correction of matrix effects, so that it allows elementary determination with adequate accuracy. The MMC and CF proved to be excellent calibration strategies for the determination of strategic (Al) and toxic (Pb) elements by LIBS, with good recoveries (ranging from 80–120%) and low relative standard deviation (RSD%) values. A detailed discussion of the advantages and limitations of each of these five calibration strategies evaluated for LIBS is presented in this study. Lead concentrations in waste PCB samples are 5–12 times higher than established by Directive 2011/65/EU, and the samples analyzed contain between 3 and 55 g kg−1 Al, being an interesting economic and recycling source for this metal.

Total reflection X-ray fluorescence spectrometry for trace determination of iron and some additional elements in biological samples

Trace elements are essential for life and their concentration in cells and tissues must be tightly maintained and controlled to avoid pathological conditions. Established methods to measure the concentration of trace elements in biological matrices often provide only single element information, are time-consuming, and require special sample preparation. Therefore, the development of straightforward and rapid analytical methods for enhanced, multi-trace element determination in biological samples is an important and raising field of trace element analysis. Herein, we report on the development and validation of a reliable method based on total reflection X-ray fluorescence (TXRF) analysis to precisely quantify iron and other trace metals in a variety of biological samples, such as the liver, parenchymal and non-parenchymal liver cells, and bone marrow–derived macrophages. We show that TXRF allows fast and simple one-point calibration by addition of an internal standard and has the potential of multi-element analysis in minute sample amounts. The method was validated for iron by recovery experiments in homogenates in a wide concentration range from 1 to 1600 μg/L applying well-established graphite furnace atomic absorption spectrometry (GFAAS) as a reference method. The recovery rate of 99.93 ± 0.14% reveals the absence of systematic errors. Furthermore, the standard reference material “bovine liver” (SRM 1577c, NIST) was investigated in order to validate the method for further biometals. Quantitative recoveries (92–106%) of copper, iron, zinc, and manganese prove the suitability of the developed method. The limits of detection for the minute sample amounts are in the low picogram range.Graphical abstract

Direct Determination of Ca, K, and Mg in Cocoa Beans by Laser-Induced Breakdown Spectroscopy (LIBS): Evaluation of Three Univariate Calibration Strategies for Matrix Matching

This study is dedicated to the direct analysis of Ca, K, and Mg by employing laser-induced breakdown spectroscopy (LIBS). Three univariate calibration strategies, namely (i) one-point and multi-line calibration (OP MLC), (ii) single-sample calibration (SSC), and (iii) two-point calibration transfer (TP CT), were evaluated and compared. Only OP MLC and TP CT presented precise and accurate results, where the trueness values ranged from 80 to 120% for most of the analyzed samples. Moreover, the standard errors for all determined elements ranged from 0.01 to less than 0.20% of the concentration in the samples. These three calibration strategies showed that they are efficient and effective for matrix matching to correct matrix effects in complex samples using only one sample as the standard.

Design of a Real-time Self-adjusting Calibration Algorithm to Improve the Accuracy of Continuous Blood Glucose Monitoring.

The aim of this study is to establish a real-time self-adjusting calibration algorithm to compensate for signal drift and sensitivity attenuation of subcutaneous implantable glucose sensors. A real-time self-adjusting in vivo calibration method was designed based on the one-point calibration model. The current signal was compensated in real-time and the sensitivity was calibrated regularly. The least squares method was used to fit the initial parameters of the model, and then, the in vivo monitored current data was calibrated. Comparing with the mean absolute relative difference (MARD) of the blood glucose concentration by the traditional one-point calibration model (22.85 ± 5.76%), the MARD of the blood glucose concentration calibrated by the real-time self-adjusting in vivo calibration method was 6.28 ± 2.31%. The accuracy of the dynamic blood glucose monitoring was effectively improved. This calibration algorithm could compensate the signal drift in real time and correct sensitivity regularly to improve the accuracy of dynamic glucose monitoring, thus significantly enhancing diabetic self-management.

An On-Chip Thermal Monitoring System With a Temperature Sensing Area of 52 $\mu$ m2 in 180-nm CMOS

In this brief, an on-chip remote thermal monitoring system with a temperature sensing area of $52~\mu \text{m}^{2}$ is proposed. To minimize the area, a diode-connected pMOS is exploited as the linear temperature sensing element and a read-out unit is shared among the sensors. The effect of parasitic resistance along the interconnect is reduced by the proposed voltage-to-time converter (VTC). For temperature independent read-out, two feedback loops are employed that exploit the stable period of a crystal oscillator. Implemented in 180-nm CMOS, the prototype IC achieves +2.3 °C/−2.2 °C error over 0 to 100 °C after one-point calibration at 25 °C.

Resolution Enhancement in Directly Interfaced System for Inductive Sensors

In this paper, a resolution enhancement method for direct interfacing of inductive sensors, without employing analog-to-digital converter and/or external driver circuit, is presented. In order to achieve better resolution with minimum relative error and current consumption factors, different schemes are implemented which vary in terms of: 1) step-input voltage provision methodology, i.e., through microcontroller ( $\mu \text{C}$ ) pin or through external supply; 2) number of switches used; and 3) method of voltage detection, i.e., either using capture module or employing built-in comparator only. The maximum achievable resolution limits are explored by reducing the lower reference voltage ( $\text{V}_{\mathrm {Ref L}}$ ) in case of detection through built-in analog comparator and/or reducing the series resistance. The one-point calibration technique is used to determine the accuracy. The experiments are performed at 16-MHz clock frequency in the inductance range of: 1) 10–100 $\mu \text{H}$ and 2) 100–1000 $\mu \text{H}$ . The results show that in the limits of a maximum current sourcing/sinking capacity of a typical $\mu \text{C}$ , i.e., 40 mA, the proposed methodology enhances the resolution to $4~\mu \text{H}$ with a relative error of 1.2 in the percentage of full-scale span (%FSS). The maximum nonlinearity error in %FSS for inductance range 10–100 $\mu \text{H}$ and 100–1000 $\mu \text{H}$ is 1.1% and <0.4%, respectively.

Characterization of Fe, Ni, Pb Standard Solution using One-point Calibration Methods

Calibration of measurement systems using well-prepared calibration materials is an important means of making traceability in chemical measurements. Traceability is established through the use of measurement standards (such as certified reference materials) that are appropriate for each parameter. Pure substance certified reference materials such as elemental standard solutions are the most commonly used for calibration, called external calibrations using one, two or multiple standards. In this study, one-point calibration method has been applied for characterizing of Fe, Ni and Pb standard solutions. The results show that the concentration of the Fe, Ni and Pb standard solutions with their relative uncertainties were found to be 997.81 ± 6.34 mg/kg, 997.61 ± 8.10 mg/kg, 1004.29 ± 8.62 mg/kg, respectively.

One-point calibration of Saha-Boltzmann plot to improve accuracy and precision of quantitative analysis using laser-induced breakdown spectroscopy

Calibration-free laser-induced breakdown spectroscopy (CF-LIBS) has recently gained attention due to its potential to overcome matrix effects on quantitative analysis using LIBS. However, the efficiency of CF-LIBS may be compromised by uncertainties in the experimental and spectroscopic parameters. To minimize these uncertainties and improve quantitative analysis, the one-point calibration (OPC) method was recently introduced to empirically correct the emission line intensities in a Boltzmann plot. In this work, we used the OPC method on a Saha-Boltzmann plot to cover a large energy range and to obtain more precise and accurate plasma temperature and electron density (Ne) values than were obtained with a Boltzmann plot using OPC method. For the analysis, we prepared two sets of sodium chloride (NaCl) samples: one with graphite and another with calcium carbonate (CaCO3). We observed matrix effects when we evaluated the calibration curves of carbon line intensity as a function of carbon concentration. Corrections by the OPC method to the Boltzmann or Saha-Boltzmann plots minimized the matrix effects and also guaranteed that the calculated plasma temperature were the same for the primary elements of each sample, suggesting that they were in local thermodynamic equilibrium. When the OPC method was applied to the Saha-Boltzmann plot, we obtained an uncertainty of less than 0.5% for plasma temperature and Ne; an r2 value of 0.994; and a root mean square relative error (RMSRE) of 8% for C concentration. Meanwhile, the traditional OPC method resulted in an uncertainty of 2.3% for plasma temperature and Ne and a validation with r2 of 0.977 and RMSRE of 13% for C concentration. These results showed that the OPC method efficiently improved the quantitative analyses possible with the Saha-Boltzmann plot using CF-LIBS.

New Reference Electrodes for Air and Moisture Stable Ionic Liquids

The use of room temperature ionic liquids (RTILs) for electrochemical applications such as fuel cells, batteries, dye-sensitized solar cells, and supercapacitors, has gained significant interest over the last decade. Despite the increase in attention, a universal reference electrode for use in RTIL electrochemistry has not been adopted. A stable, easy to prepare, and reproducible reference electrode, analogous to Ag/AgCl reference electrodes for aqueous electrochemistry, is crucial for accurately determining redox potentials as well as for comparing these potentials between RTILs and between research labs. Electrochemical work in RTILs often rely on quasi-reference electrodes (QREs),1 such as Ag or Pt wire, which must be calibrated by the addition of a redox couple (e.g. ferrocene/ferrocenium) after each electrochemical measurement. These quasi-reference electrodes are difficult to reproduce, likely due to the quality of the wire used and the presence of surface adsorbates. Furthermore, they have been known to exhibit potential drift during use, with 10s to 100s of mV drift often observed. Ferrocene is added after the experiment, however this one-point calibration of the QRE does not necessarily apply throughout the entire experiment, as the QRE may drift during the measurement.2 We report on reference electrodes designed for use in ionic liquids, which exhibit stable potential over several months of experimental use. One successful example is based on a silver wire coated with silver sulfide.3 The reference electrode potential is determined by the concentrations of Ag+ and S2 −, which are established by the solubility of the Ag2S coating on the Ag wire. Our reference electrode can be prepared and used in a normal air atmosphere, and does not need to be assembled and used in a glovebox, or protected from light. The reference electrode has been characterized by voltammetry measurements of ferrocene and cobaltocenium hexafluorophosphate, and was found to slowly drift to more positive potentials at a rate of <1 mV/day for five RTILs investigated over the course of 2+ months. Funding was provided by Lawrence Livermore National Laboratory Directed Research and Development (LDRD) Grant 17-ERD-047. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. IM release LLNL-ABS-748348. (1) Electrochemical aspects of ionic liquids, 2nd ed.; Ohno, H., Ed.; John Wiley & Sons Inc., 2011. (2) Torriero, A. A. J.; Sunarso, J.; Howlett, P. C. Electrochim. Acta 2012, 82, 60–68. (3) Horwood, C.; Stadermann, M. Electrochem. commun. 2018, 88, 105–108.

Multimodal Wrist Biosensor for Wearable Cuff-less Blood Pressure Monitoring System

We propose a multimodal biosensor for use in continuous blood pressure (BP) monitoring system. Our proposed novel configuration measures photo-plethysmography (PPG) and impedance plethysmography (IPG) signals simultaneously from the subject wrist. The proposed biosensor system enables a fully non-intrusive system that is cuff-less, also utilize a single measurement site for maximum wearability and convenience of the patients. The efficacy of the proposed technique was evaluated on 10 young healthy subjects. Experimental results indicate that the pulse transit time (PTT)-based features calculated from an IPG peak and PPG maximum second derivative (f14) had a relatively high correlation coefficient (r) to the reference BP, with −0.81 ± 0.08 and −0.78 ± 0.09 for systolic BP (SBP) and diastolic BP (DBP), respectively. Moreover, here we proposed two BP estimation models that utilize six- and one-point calibration models. The six-point model is based on the PTT, whereas the one-point model is based on the combined PTT and radial impedance (Z). Thus, in both models, we observed an adequate root-mean-square-error estimation performance, with 4.20 ± 1.66 and 2.90 ± 0.90 for SBP and DBP, respectively, with the PTT BP model; and 6.86 ± 1.65 and 6.67 ± 1.75 for SBP and DBP, respectively, with the PTT-Z BP model. This study suggests the possibility of estimating a subject’s BP from only wrist bio-signals. Thus, the six- and one-point PTT-Z calibration models offer adequate performance for practical applications.

LC–MS/MS determination of N-acetylaspartic acid in dried blood spot for selective screening of Canavan disease

Canavan disease is a serious rare neurometabolic disorder characteristic of an accumulation of N-acetylaspartic acid (NAA) in biological fluids. Its determination mainly in urine is the key part of the diagnostic procedure. Despite the several advantages of using dried blood spot (DBS) samples for clinical analysis, it has not been reported for this purpose so far. Therefore, this work was focused on the development of a HPLC–MS/MS method for the determination of NAA in a dried blood spot. The method using a stable isotope-labeled internal standard was elaborated and partially validated, with an estimated limit of quantification of 0.06 μmol dm−3, and with intra-day and inter-day precisions up to 4.1 and 8.0%, respectively. The elaborated method was applied for the NAA determination in healthy controls and in two siblings with Canavan disease. There were three quantification approaches evaluated using one-point calibration as well as calibration curves with and without matrix. The results correlated very well and exhibited parallelism of one-point calibration and calibration curve approaches. The mean NAA concentrations determined in DBS of control newborns and older children (10 months–7 years) were 0.9 and 0.5 μmol dm−3, respectively. Patients were clearly distinguished from controls, considering the NAA concentrations were more than 10 times higher than in an aged-matched control group.

Accuracy improvement of quantitative analysis for major elements in laser-induced breakdown spectroscopy using single-sample calibration

Accurate determination of major elements using limited standard samples is always a big challenge in laser-induced breakdown spectroscopy (LIBS). Based on a simple calculation process, we propose a new one-point calibration method called single-sample calibration LIBS (SSC-LIBS) to build the calibration and improve the accuracy of determination of major elements. In this work, several major elements (Fe, Cu, Zn, Ni, Cr, Nb, and Mo) in three sets of matrix-matched certified samples were determined without sample preparation. The results showed that compared with multipoint calibration LIBS (MPC-LIBS), the R2, RMSECV, and ARE of Cu elements were improved from 0.40 to 0.97, 3.55 wt% to 0.76 wt%, and 5.19% to 1.05%, respectively, while the ARSD decreased from 16.22% to 1.15%. Furthermore, the AREs in the concentration ranges of 1–10, 10–20, 30–40, 50–60, 60–70, and 80–100 wt% were 5.16%, 2.55%, 1.75%, 1.69%, 1.05%, and 0.44%, respectively, with almost all less than 5%, as calculated by SSC-LIBS. These results demonstrated that SSC-LIBS can improve the accuracy and stability of detecting major elements using only one standard sample, which can greatly promote the application of LIBS.

Quantitative determination of 58 aromatic amines and positional isomers in textiles by high-performance liquid chromatography with electrospray ionization tandem mass spectrometry

A straightforward method for simultaneous determination of 58 aromatic amines (AAs) in clothing textiles is described. Of the tested amines, 22 are known carcinogens and regulated under European law. Further unregulated amines, which are suspected to be carcinogenic or mutagenic, are also expected to occur in textiles. The focus of this study was to obtain a multimethod with regulated and unregulated AAs and to separate different positional isomers of specific amines. To achieve this goal, the HPLC parameters such as column phase chemistry and mobile phase pH were optimized. All other amines were separated with the same conditions evaluated for the positional isomers. The sample preparation was reduced to a minimum in accordance to DIN EN 14362-1. After reductive cleavage and dilution of the extracts, the samples were prepared for LC–MS/MS analysis. Further cleanup of the samples with diatomaceous earth was no longer required with this modified sample preparation.The method was validated by spiking the extracts of blank textiles with the chosen amines. Lower Limits of Quantification (LLOQs) ranged from 1 to 10 mg kg−1. Excellent linearity from 10 to 500 μg L−1 was obtained with coefficients (r) higher than 0.99 allowing a one-point calibration (300 μg L−1 corresponding to 60 mg kg−1 in textiles) forced through zero for the samples. Recovery ranged from 88 to 116% with intra- and inter-day precision values of 1.8–12.1%. The accuracy of this method was tested by a certified reference material (iis18A03, Institute for laboratory Studies, the Netherlands) and showed excellent recoveries higher than 95%.Finally, the described method was successfully applied on 150 real samples with different textile fibres and colours. Positive results were confirmed by means of the spectral library and with the ion ratios.

One-point and multi-line calibration method in laser-induced breakdown spectroscopy.

The calibration-free laser-induced breakdown spectroscopy (CF-LIBS) and its variations are low cost, short time consumption, and high adaptability. However, seeking a more flexible and simple quantitative analysis method remains a challenge. A one-point and multi-line calibration (OP-MLC) was presented as a simple quantitative analysis method of LIBS. The results showed that OP-MLC-LIBS method can achieve quantitative analysis using only one standard sample, and the average relative errors (AREs) are 9, 22, 21 and 36% for Mn, Cr, Ni and Ti elements in six tested low-alloy steel samples, respectively. The method requires neither a large number of standard samples nor complicated calculations, which provides a flexible and low-cost quantitative analysis approach for development and application of LIBS.