Spectro Analysis (or Spectroscopic Analysis) is an analytical technique used to determine the elemental composition of materials by measuring the interaction of light (or other radiation) with matter. It is widely used in metallurgy, chemistry, environmental science, and quality control to identify and quantify elements in solids, liquids, and gases.
Types of Spectroscopic Analysis
- Optical Emission Spectroscopy (OES)
– Principle: Excites atoms in a sample (via spark or arc) and measures emitted light wavelengths.
– Used for: Metal alloy identification (e.g., PMI – Positive Material Identification).
– Example: Checking stainless steel grades (304 vs. 316).
- X-ray Fluorescence (XRF)
– Principle: Bombards sample with X-rays, causing secondary X-ray emission (fluorescence).
– Used for: Non-destructive metal, mineral, and coating analysis.
– Example: Lead detection in paint, alloy verification.
- Atomic Absorption Spectroscopy (AAS)
– Principle: Measures absorption of light by free atoms in a gaseous state.
– Used for: Trace metal analysis (ppm/ppb levels) in water, food, and pharmaceuticals.
– Example: Detecting mercury in drinking water.
- Inductively Coupled Plasma (ICP) Spectroscopy
– ICP-OES (Optical Emission) – Measures light emitted by excited ions.
– ICP-MS (Mass Spectrometry) – Detects ions based on mass-to-charge ratio.
– Used for: Ultra-trace element detection (e.g., heavy metals in soil).
- Fourier Transform Infrared (FTIR) Spectroscopy
– Principle: Measures absorption of infrared light by molecular bonds.
– Used for: Organic compound identification (polymers, lubricants, contaminants).
- Laser-Induced Breakdown Spectroscopy (LIBS)
– Principle: Uses a laser pulse to vaporize material, then analyzes emitted light.
– Used for: Fast, portable elemental analysis (e.g., scrap metal sorting).
Applications of Spectro Analysis
Material Verification (PMI for metals in oil & gas, aerospace).
Quality Control (checking alloy composition in manufacturing).
Environmental Testing (heavy metals in water/soil).
Failure Analysis (identifying contaminants in failed components).
Forensics & Archaeology (elemental profiling of artifacts).
Advantages of Spectroscopic Techniques
Fast & accurate (real-time results in seconds).
Non-destructive (XRF, LIBS) – No sample damage.
Detects trace elements (ppm/ppb sensitivity in ICP-MS).
Portable options (XRF, LIBS) – Field testing available.
Limitations
Sample prep needed (for AAS, ICP, OES – may require digestion).
Not all methods detect light elements (e.g., XRF struggles with carbon).
Equipment cost (high-end ICP-MS is expensive).
Standards for Spectro Analysis
– ASTM E415 (Spark OES for Carbon & Low-Alloy Steel)
– ISO 3497 (XRF Coating Thickness Measurement)
– EPA 6010D (ICP-OES for Environmental Testing)
When to Use Spectro Analysis?
– Need to verify metal composition? → OES or XRF
– Testing for trace contaminants? → ICP-MS or AAS
– Field-based material ID? → Portable XRF or LIBS
