The 3 Most Common Elemental Analysis Techniques in NDT

Table of Contents

• Introduction
• Elemental Analysis Techniques
• Emerging Technologies and Innovations
• Conclusion
• FAQs

Introduction

What is elemental analysis? Elemental analysis, within the context of scientific inquiry, pertains to the procedure of discerning the elemental composition  of a given substance. The intention of this blog is to offer insights on common elemental analysis techniques that are prevalent and elemental analysis methods utilized across diverse industries.

Common Elemental Analysis Techniques

Elemental analysis is performed to determine the composition of substances at the elemental level. This analysis involves techniques such as mass spectrometry and atomic absorption spectroscopy to quantify the amount of each element present in a sample. By identifying the elements present, scientists can gain insight into the properties and behaviour of the substance being studied.

There are a few common methods that are widely used.

X-Ray Fluorescence (XRF)

X-ray Fluorescence (XRF) is a non-destructive analytical technique used to determine the elemental composition of a material. In XRF, a sample is irradiated with X-rays, typically generated by an X-ray tube. The high-energy X-rays cause inner-shell electrons in the atoms of the sample to be ejected. When outer-shell electrons fill these vacancies, characteristic X-rays are emitted.

The energy and intensity of these emitted X-rays are then detected and analyzed to identify the elements present in the sample and quantify their concentrations. XRF is widely employed in various fields, including archaeology, environmental science, geology, and industrial quality control, due to its capability for rapid and simultaneous multi-element analysis.

XRF comes in two main forms: energy-dispersive XRF (EDXRF) and wavelength-dispersive XRF (WDXRF). EDXRF utilizes a semiconductor detector to measure the energy of the emitted X-rays directly, while WDXRF uses a crystal monochromator to separate the X-rays based on their wavelengths before detection.

Both variants offer advantages depending on the specific analytical requirements. XRF’s non-destructive nature and ability to analyze a wide range of materials make it a valuable tool for determining the elemental composition of samples without the need for extensive sample preparation.

Optical Emission Spectroscopy (OES)

Optical Emission Spectroscopy (OES) is a technique used for elemental analysis in diverse samples. The process begins with the preparation of the sample, which is then subjected to high temperatures, causing atomization and the formation of excited atoms. This excitation is achieved through exposure to a high-energy source such as a flame or plasma. As the excited atoms return to lower energy states, they emit light at characteristic wavelengths unique to each element.

The emitted light is collected, separated into individual wavelengths using a monochromator, and detected by a photodetector. By analyzing the emitted wavelengths and their intensities, the elemental composition of the sample can be determined. Calibration with standard samples is typically employed to quantify elemental concentrations accurately.

Commonly applied in the analysis of metals and alloys, OES offers rapid and simultaneous multi-element analysis. Variations of OES instruments, such as inductively coupled plasma optical emission spectrometry (ICP-OES) and flame atomic emission spectrometry (FAES), cater to different analytical needs.

OES is prized for its efficiency and reliability in providing valuable insights into the elemental makeup of various materials, making it a valuable tool in fields such as metallurgy, environmental monitoring, and quality control.

Laser Induced Breakdown Spectroscopy (LIBS)

Laser-Induced Breakdown Spectroscopy (LIBS) is an analytical technique that utilizes laser pulses to generate a plasma on the surface of a sample, allowing for the analysis of its elemental composition. The process begins with focusing a high-energy laser pulse onto the sample, leading to rapid heating and vaporization, creating a microplasma.

The intense heat causes the atoms to reach excited states, and as they return to lower energy states, they emit characteristic light that is captured and analyzed for elemental identification. LIBS offers several advantages, including its ability to analyze samples in situ without the need for extensive sample preparation, making it suitable for applications in fields such as environmental monitoring, geology, and material science.

LIBS is prized for its versatility and rapid data acquisition, providing real-time elemental analysis. The technique is particularly useful for analyzing solid, liquid, or gas samples, and it has found applications in diverse fields, including industrial quality control, forensic science, and even planetary exploration. Additionally, LIBS allows for the detection of a wide range of elements, making it a powerful and non-destructive tool for elemental characterization across various materials and environments.

Emerging Technologies and Innovations

The field of elemental analysis has witnessed significant advancements, ushering in a new era of technology-driven innovation. These developments have paved the way for next-generation elemental analysis methods aimed at enhancing accessibility and efficiency:

Portable Devices

The advent of portable XRF, LIBS and OES devices represented a groundbreaking development in elemental analysis technology. These compact and lightweight instruments enable on-site analysis in remote locations, eliminating the need for sample transportation to centralized laboratories. Portable PMI devices empower field researchers with chemical analysis techniques, environmental scientists, and exploration geologists to perform real-time elemental analysis with unprecedented ease and convenience.

Miniaturised ICP Systems

Miniaturised ICP systems represent a notable advancement in elemental analysis instrumentation. By downsizing traditional ICP instruments, these compact systems offer improved portability and reduced sample consumption.

Additionally, miniaturised ICP systems are often more cost-effective than their larger counterparts, making them more accessible to a wider range of users. These systems also typically require less maintenance and have faster analysis times, increasing efficiency in elemental analysis processes.

Automated Sample Preparation Techniques

Automation has revolutionised elements of analysis workflows, streamlining sample preparation processes and enhancing analytical throughput. Automated sample preparation techniques, such as robotic liquid handling systems and microfluidic devices, enable high-throughput sample processing with minimal manual intervention. 

Automated sample preparation techniques have significantly reduced the risk of human error and increased the reproducibility of results in analytical laboratories. Additionally, automated sample preparation allows for more efficient use of resources and time, ultimately leading to faster turnaround times for results. 

Conclusion

Elemental analysis plays a crucial role in various scientific and industrial fields by providing insights into the elemental composition of alloys. Through techniques like XRF, OES and LIBS researchers and analysts can accurately identify and quantify elements in diverse samples, ranging from environmental samples to scrap metals.

The selection of an appropriate elemental analysis technique depends on factors such as sample characteristics, sensitivity requirements, and cost considerations. Each technique has its own set of advantages and limitations, making it essential for analysts to carefully evaluate their options based on specific analytical needs and resource constraints.