Laser Induced Breakdown Spectroscopy of Liquid Samples
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Solution Overview
Problem
Current methods for elemental composition analysis, particularly using laser-induced breakdown spectroscopy (LIBS), face challenges in accurately and reliably analyzing liquid samples due to inconsistent plasma plume generation, light scattering, and the inability to perform real-time, low-maintenance analysis, limiting their applicability in industries like petroleum and pharmaceuticals.
Innovation Solution
A compact, portable LIBS apparatus that uses a pulsed laser to generate a plasma plume in liquid samples, coupled with an optical spectrometer and a movable stage for precise sample positioning, allowing for high-accuracy, real-time analysis of both liquid and solid samples without sample preparation, and capable of measuring trace elements with minimal equipment and waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional ICP-OES is used for multi-element analysis, then detection limits for metals can reach sub-ppm levels, but complex sample preparation including acid digestion is required and hazardous chemical waste is generated
Solution Approach 1:
The patent extracts and eliminates the harmful acid digestion step from the analysis process by using laser ablation to directly vaporize and atomize the sample in its native state, thereby removing the need for complex sample preparation while maintaining detection capabilities
Solution Approach 2:
The laser ablation process enables the sample to self-atomize and self-excite through the high-energy laser pulse, eliminating the need for external chemical digestion processes and reducing reliance on complex preparatory procedures
2Adaptability or versatility
If ICP-OES is used for elemental analysis, then comprehensive multi-element detection is achieved, but high power requirements and large equipment dimensions impede field measurement use
Solution Approach 1:
The patent replaces the complex inductively coupled plasma generation system with a simpler laser-based ablation and excitation system, substituting mechanical/electromagnetic plasma generation with optical field-based excitation, thereby reducing power requirements and enabling portability
Solution Approach 2:
The laser system serves multiple functions simultaneously - ablation, vaporization, atomization, and excitation - consolidating what would traditionally require separate systems into a single multi-functional device, thereby reducing overall power consumption and equipment size
3Productivity
If LIBS is used for liquid sample analysis, then rapid vaporization can be achieved, but uncontrolled droplet formation and light scattering occur
Solution Approach 1:
The patent uses periodic pulsed laser irradiation with controlled timing and frequency to vaporize liquid samples, allowing the plasma to form and cool in a controlled cyclic manner, which prevents uncontrolled droplet formation while maintaining rapid analysis capability
Solution Approach 2:
The patent optimizes multiple parameters including laser pulse duration, repetition rate, and energy density to achieve controlled vaporization that minimizes light scattering from droplets while maintaining high analysis throughput, thereby improving measurement consistency
4Measurement precision
If LIBS is used for solid sample analysis, then light element detection sensitivity is improved, but excessive variability in plasma plume generation occurs
Solution Approach 1:
The patent introduces a controlled atmosphere or carrier gas as an intermediary medium that stabilizes plasma plume formation by providing a consistent chemical environment, thereby reducing variability in excitation conditions while preserving the sensitivity advantages of LIBS for light elements
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
The apparatus provides high sensitivity and reproducibility in elemental analysis, enabling rapid, reliable measurement of major, minor, and trace elements in various samples, improving analytical efficiency and reducing operational costs and environmental impact.
Implementation Method 1
laser induced breakdown spectroscopy (LIBS)
Implementation Method 2
laser ablation process
Implementation Method 3
optical emission spectroscopy
Data Source
AI summary
Chemical composition of liquid phase samples is determined based on laser induced ablation spectroscopy of droplets. An aerosol jet comprising a carrier gas and liquid phase sample droplets, less than about 10 microns in diameter, is formed. An emissive plasma plume is generated from the sample droplets using a pulsed laser to deposit energy at a focal point in the aerosol jet. Light from the plasma plume is gathered with a concave mirror and focused into one end of a fiber optic lightguide. The lightguide can transmit spectral emissions from the plume to a spectrometer/detector which can send wavelength and intensity values to a computer. The computer is operable to determine a liquid sample composition based on the wavelength and intensity values.