# Quantitative Analysis of Cerium-Gallium Alloys Using a Hand-Held Laser Induced Breakdown Spectroscopy Device

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## Abstract

**:**

## 1. Introduction

## 2. Sample Manufacturing

## 3. Spectral Acquisition and Pre-Processing

_{2}F

_{2}detection with this device [12] and based on well-established spectral pre-processing techniques that aid in quantitative analysis [26,27]. First, a signal removal method algorithm was employed to subtract the baseline from the spectra. Next, a five-point Savitzky–Golay (SG) filter was employed after analysis determined that it removed continuum noise from the peak while maintaining the peaks and valleys in the spectra. Finally, a third-order noise median method (NMM) function was used to further remove noise from the peak wings. The applied filter is shown in Figure 2. The filter parameters were optimized to maximize noise reduction and minimize peak information loss. Ensuring the filtering algorithms did not clip the peaks allowed for the highest accuracy in the peak ratio calculations for the calibration curves discussed further in Section 5.

## 4. Analytical Line Selection

## 5. Univariate Calibration Curves and Limits of Detection

## 6. Multivariate Analysis

## 7. Concentration Mapping

## 8. Conclusions

## Author Contributions

## Funding

## Acknowledgments

## Conflicts of Interest

## References

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**Figure 2.**Ce II 394.3-nm emission peak after effective smoothing and noise reduction by a five-point Savitzky–Golay (SG) filter.

**Figure 3.**Ga I emission peaks centered at (

**a**) 287.4 nm and (

**b**) 294.4 nm. The peak intensities increase as the gallium concentration in the alloy increases.

**Figure 4.**Ce II emission peaks centered at (

**a**) 394.3 nm and (

**b**) 413.8 nm. The peak intensities decrease as the Ga concentration in the alloy increases.

**Figure 5.**Calibration curve from line intensity ratios of the Ga I 287.4-nm emission to the (

**a**) Ce II 394.3 nm (

**b**) and the Ce II 413.8-nm emission lines. The regression fit is shown with a solid red line, while errors in the regression coefficients are plotted with the dashed red lines.

**Figure 6.**Calibration curve from line intensity ratios of the Ga I 294.4-nm emission to the (

**a**) Ce II 394.3-nm (

**b**) and the Ce II 413.8-nm emission lines.

**Figure 7.**Multiple regression plot fitting ratios of the Ga I 287.4-nm peak intensity to a model determining Ga concentration based on the correlation between peak intensity ratios.

**Figure 8.**(

**a**) Photograph of the 3% Ga cerium alloy sample used in the mapping analysis and (

**b**) surface Ga concentration map of the sample. The color map represents the localized weight percent of gallium ranging from zero to six percent.

**Table 1.**Fitting parameters for calibration curves for the equation y = ax + band limit of detection (LOD).

Line Ratio | a | $\mathit{\delta}$a | b | $\mathit{\delta}$b | R${}^{2}$ | LOD (wt%) |
---|---|---|---|---|---|---|

287.4 nm/394.3 nm | 0.098 | 0.0294 | 0.0072 | 0.0036 | 0.9669 | 0.335 |

287.4 nm/413.8 nm | 0.106 | 0.0320 | 0.0066 | 0.0032 | 0.9661 | 0.318 |

294.4 nm/394.3 nm | 0.053 | 0.0251 | 0.0029 | 0.0033 | 0.4855 | 3.524 |

294.4 nm/413.8 nm | 0.063 | 0.0243 | 0.003 | 0.0033 | 0.5637 | 3.429 |

**Table 2.**Fit parameters for multivariate regression of data points using Ga I 287.4-nm line intensities.

Parameter | Value |
---|---|

b${}_{0}$ | 0.006 |

b${}_{1}$ | 2.934 |

b${}_{2}$ | 5.886 |

$\delta $b${}_{0}$ | 0.001 |

$\delta $b${}_{1}$ | 0.341 |

$\delta $b${}_{2}$ | 0.333 |

R${}^{2}$ | 0.994 |

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**MDPI and ACS Style**

Rao, A.P.; Cook, M.T.; Hall, H.L.; Shattan, M.B.
Quantitative Analysis of Cerium-Gallium Alloys Using a Hand-Held Laser Induced Breakdown Spectroscopy Device. *Atoms* **2019**, *7*, 84.
https://doi.org/10.3390/atoms7030084

**AMA Style**

Rao AP, Cook MT, Hall HL, Shattan MB.
Quantitative Analysis of Cerium-Gallium Alloys Using a Hand-Held Laser Induced Breakdown Spectroscopy Device. *Atoms*. 2019; 7(3):84.
https://doi.org/10.3390/atoms7030084

**Chicago/Turabian Style**

Rao, Ashwin P., Matthew T. Cook, Howard L. Hall, and Michael B. Shattan.
2019. "Quantitative Analysis of Cerium-Gallium Alloys Using a Hand-Held Laser Induced Breakdown Spectroscopy Device" *Atoms* 7, no. 3: 84.
https://doi.org/10.3390/atoms7030084