webtrax Certificate of Analysis (COA) Explained: What to Look for in 5N+ HIgh
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Certificate of Analysis (COA) Explained: What to Look for in 5N+ HIgh Purity Aluminum

Certificate of Analysis (COA) Explained: What to Look for in 5N+ High Purity Aluminum

In the world of high-tech electronics, research, and specialty applications, the purity of materials like aluminum is critical – trace impurities can cause defects or failures. At HPA Distribution (High Purity Aluminum), we specialize in ultra-pure aluminum starting at 99.99% (4N) purity, with our flagship offerings in 5N (99.999%) and 6N (99.9999%) grades. Our products include high purity aluminum blocks, foil, ingots, pellets, plates, rods, rod coil, sheets, sputtering targets, and wire.

Verifying that purity requires a reliable Certificate of Analysis (COA)—a critical document that confirms the material meets stringent standards.

If you're sourcing 5N aluminum or 6N aluminum for semiconductors, superconductors, or advanced research, this guide explains COA’s, key indicators for 5N+ aluminum, and why we use Glow Discharge Mass Spectrometry (GDMS) for all our premium-grade COA’s.  We will also compare GDMS with Inductively Coupled Plasma (ICP) methods for metal purity testing.

What is a Certificate of Analysis (COA) for High Purity Aluminum?

A high purity aluminum COA is an official report issued by the manufacturer or a third-party lab that details a batch’s chemical composition and purity level. It lists impurities in parts per million (ppm) or parts per billion (ppb), confirming alignment with specifications like 5N aluminum (less than 10 ppm total impurities) or 6N aluminum (less than 1 ppm total impurities).

Why it matters? In applications like thin-film deposition or high-frequency electronics, even trace impurities can reduce performance. A robust COA for aluminum ensures quality, traceability, and compliance with industry standards such as ASTM or ISO.

 

Understanding Purity Levels: What Does 5N+ Mean?

  • 4N Aluminum (99.99%): Total impurities ≤ 100 ppm - suitable for many industrial uses but may not suffice for ultra-sensitive applications.
  • 5N Aluminum (99.999%): Total impurities ≤ 10 ppm - perfect for research, electronics, and high purity aluminum sputtering targets.
  • 6N Aluminum (99.9999%): Total impurities ≤ 1 ppm – essential for quantum computing or advanced optics.

In 5N+ grades, watch key impurities such as iron (Fe), silicon (Si), copper (Cu), magnesium (Mg), and titanium (Ti) that impact conductivity and integrity.

 

GDMS Spectrometry: The Preferred Method for Our 5N+ Aluminum COAs

At High Purity Aluminum, we generate all COAs for our 5N and higher purity products using Glow Discharge Mass Spectrometry (GDMS) – the most accurate method for trace analysis in metals.

Highlights of a GDMS COA:

  • Comprehensive Element Coverage: GDMS scans for up to 70+ elements.  We do not normally test for Gases, such as carbon (C), hydrogen (H), oxygen (O), and nitrogen (N), although we have typical levels listed on our typical analysis section.
  • Ultra-Low Detection Limits: Measures impurities down to ppb levels (e.g., <0.1 ppb for some elements), crucial for 6N aluminum purities.
  • Direct Solid Sampling: No sample dissolution required, reducing contamination risks and providing a true representation of the bulk material.
  • Quantitative Results: Lists each impurity's concentration, total impurity sum, and calculated purity percentage (e.g., "99.9995% Al with 4.5 ppm total impurities").
  • Batch Traceability: Includes lot number and purity reference for full accountability.
  • Visual Format: Often presented in a table with elements in rows and concentrations in columns.

When reviewing a GDMS COA for 5N aluminum, look for:

  • Total impurities summing to ≤10 ppm.
  • No single element exceeding expected thresholds (e.g., Fe <1 ppm for electronics-grade).

 

GDMS vs. ICP: A Comparison for Metal Purity Testing

While both GDMS and Inductively Coupled Plasma (ICP) methods analyze impurities, they differ in approach, accuracy, and suitability for high purity aluminum.

Key Differences:

Aspect

GDMS (Glow Discharge Mass Spectrometry)

ICP (Inductively Coupled Plasma)

Sample Preparation

Direct sputtering of solid sample—no acids low contamination risk

Acid dissolution – risks introducing impurities

Detection Limits

ppb to sub-ppb (e.g., 0.01 ppb for many metals). Ideal for ultra-pure aluminum

ppm to ppb, but less sensitive for volatile or light elements.

Element Coverage

Broad (50-70 elements), including non-metals like C, N, O, upon request

Basic (10-30 elements) (add-ons for non-metals)

Accuracy for High Purity

Superior in solids; minimal  interference

Good for 4N, but dilution errors in ultra pure samples

Cost and Speed

Higher cost, slower - unmatched precision

Lower cost, faster, suitable for routine checks.

Best For

 

Semiconductors, aerospace, and research (ppb-level critical)

General industrial testing

GDMS delivers a contamination-free, accurate view, which is why we use this exclusively for high purity aluminum blocks, foil, plates, rods, sheet and wire, among other shapes. 

 

Why Choose High Purity Aluminum with GDMS-Backed COAs?

Every batch of our ultra pure aluminum – 5N and 6N aluminum includes a GDMS COA for transparency and trust.  Don’t risk performance – demand GDMS-verified ultra pure aluminum. 

Browse our high purity aluminum products or contact us for custom shapes and sizes. For more tips on selecting ultra pure aluminum, check our resources or reach out— we're here to support your high-tech success.

Note: This post is for educational purposes. Always consult your application's requirements when evaluating materials.

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