LIBS Carbon Detection via C-N Radical Resonant Excitation
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Solution Overview
Problem
Laser-induced breakdown spectroscopy (LIBS) faces challenges in detecting carbon elements due to weak spectral lines in the vacuum ultraviolet region, which are easily interfered with by matrix spectra and are difficult to detect in samples with low carbon content, especially in industrial and remote applications.
Innovation Solution
The method involves ablating a sample with a laser to create C—N radicals, which are then resonantly excited using a wavelength-tunable laser to enhance fluorescence signals, allowing for selective enhancement of carbon element spectra and improved detection sensitivity while minimizing matrix interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If carbon detection is performed using conventional LIBS in the VUV region, then elemental information can be obtained, but the spectral lines are very weak and easily interfered by matrix spectrum
Solution Approach 1:
The patent extracts the carbon detection signal from the interfering matrix spectrum by forming C-N radicals with characteristic spectral lines in the visible region, separating the carbon signal from the VUV region where matrix interference occurs
Solution Approach 2:
The patent introduces nitrogen as an intermediary substance that reacts with carbon to form C-N radicals, which serve as a mediator to transfer carbon detection to a different spectral region (visible instead of VUV) where detection is less interfered
2Measurement precision
If noble gas protection is used to avoid VUV absorption by air, then spectral acquisition efficiency is improved, but the method cannot achieve gas protection of the whole spectrum collection light path in remote detection
Solution Approach 1:
The patent changes the detection parameter from VUV spectral region to visible spectral region by detecting C-N radical fluorescence, eliminating the need for vacuum or noble gas protection and enabling remote detection applications
3Measurement precision
If multi-element spectrum correction algorithm is used to derive carbon content, then carbon detection is enabled, but the method is limited by other elements in the sample and only suitable for samples with the same matrix
Solution Approach 1:
The patent extracts carbon detection from matrix-dependent algorithms by forming C-N radicals with characteristic spectral lines that can be selectively detected, separating carbon analysis from the constraints of multi-element correction algorithms
Solution Approach 2:
The patent uses C-N radicals as an intermediary that provides a universal detection mechanism applicable to different sample matrices, replacing matrix-specific correction algorithms with a more versatile radical-based detection approach
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the detection sensitivity of carbon elements by using C—N radical signals in the visible range, reducing matrix interference and enabling remote, online, and industrial analysis without the need for vacuum or noble gas protection, thus overcoming limitations of existing methods.
Implementation Method 1
resonant excitation of the C—N radicals is carried out by using a wavelength-tunable laser to obtain fluorescence signals of the C—N radicals
Implementation Method 2
obtain fluorescence signals of the C—N radicals
Implementation Method 3
a pulsed laser beam is used to ablate the surface of a sample to generate plasma
Implementation Method 4
generate plasma, and elemental information about the species and content contained in the sample is obtained
Data Source
AI summary
The present invention belongs to the field of laser plasma emission spectrometry, and in particular relates to a method for improving the detection sensitivity on a carbon element in laser-induced breakdown spectroscopy. The method specifically comprises the following steps: ablating the surface of a sample to be tested by using a laser beam emitted so as to rapidly heat the surface of the sample and the ambient air close to the surface of the sample into plasma, atomize carbon in the sample and nitrogen in the ambient gas, and combine carbon with the nitrogen into C—N radicals; tuning a wavelength-tunable laser to a wavelength needed by stimulated absorption transition of C—N radicals, and outputting a laser beam to radiate the plasma so that stimulated absorption transition of C—N radicals is carried out, then fluorescent signals are emitted with spontaneous radiative transition; collecting and recording an emission fluorescence spectrum of the C—N radicals; and qualitatively or quantitatively analyzing on carbon element. By adopting the method provided by the invention, in a case of hardly affecting the matrix spectrum, C—N radical signal can be enhanced in high selectivity, thereby avoiding the interference generated by the matrix, and spectrum signals of the carbon element in the plasma can be enhanced, thereby improving the detective sensitivity of LIBS on carbon element.