How to Quickly Check a COA to Avoid Production Risks
In the industrial chemical sector, the Certificate of Analysis (COA) is often regarded as the “passport” of raw materials. However, this is one of the most dangerous misconceptions in chemical manufacturing. A COA is merely an analytical report of a single sample, at a single point in time, according to a minimal set of parameters. It does not represent long-term stability, does not reflect compatibility with your production system, and cannot predict operational risks. So, how can you quickly check a COA to avoid production risks?
In reality, many production issues stem from shipments where the COA is technically correct, yet:
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The system reacts incorrectly
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Equipment degrades faster than expected
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Efficiency decreases over time
This article provides engineers and purchasing teams with a fast, accurate, and sufficient COA checking process to eliminate risks at the raw material stage.
1. Understand the True Nature of a COA in Industrial Chemistry
A COA is not just a certificate stating that a material meets standards. It is a commitment to the physicochemical properties of a specific batch (Batch/Lot number).
Many buyers make the mistake of looking only at the Assay value (active content). While important, it does not tell the full story.
A standard COA typically includes:
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Active content (Assay)
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Major impurities
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Moisture content
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pH
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Density or viscosity
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Color and appearance
From a chemical standpoint, industrial chemicals always contain impurities:
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Heavy metals: Fe, Cu, Pb
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Foreign ions: Cl⁻, SO₄²⁻
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Residual solvents
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Unreacted isomers
These components are not “inert.” They can:
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Act as unwanted catalysts
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Alter reaction kinetics
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Cause uncontrolled precipitation or polymerization
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Shift phase equilibria
A COA shows that these impurities exist but does not indicate their effect on your system.
2. Principles for Reading a COA in Two Minutes
COAs should be read with a technical mindset, not an administrative one.
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Don’t ask: “Does this COA pass?”
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Ask: “Is this COA compatible with my production system?”
3. Fast COA Checking Process for Engineers and Purchasing Teams
Step 1: Verify Actual Purity
Do not only look at numbers like 98%, 99%, or 99.5%. In industrial chemistry, the remaining 1–2% can determine risk.
Technical example:
NaOH 98% often contains:
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Na₂CO₃
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NaCl
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Residual Fe metals
In cosmetics or pharmaceutical manufacturing, just a few ppm of Fe³⁺ can catalyze oxidation, causing:
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Product discoloration
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Strange odors during storage
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Emulsion instability
Key questions:
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What method was used to measure purity?
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Is there a trace metals report?
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Is there data on batch-to-batch variation?
Step 2: Check Batch-to-Batch Stability
In production, stability is more important than nominal value.
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A 98.5% chemical stable ±0.1% is better than 99.5% fluctuating ±1%.
Instability leads to:
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Actual concentration deviation
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Reaction rate changes
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Viscosity and density fluctuations
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Freezing or boiling point shifts
Consequences:
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Continuous process adjustments
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Loss of quality control
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Increased energy consumption
Questions to ask:
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Is historical quality data available?
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Are Statistical Process Control (SPC) measures in place?
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Can raw materials be traced?
Step 3: Evaluate Equipment-Related Parameters
A chemical affects not only the product but also fixed assets.
Important indicators:
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pH
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Inorganic salt content
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Crystallization tendency
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Insoluble components
Typical system damage process:
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Corrosion & Fouling – Unstable pH and inorganic impurities accelerate corrosion of tanks, pipes, and agitators.
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Sensor Deviations – Foreign ions affect conductivity or refractive index, sending incorrect PLC signals.
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Filter Clogging – Insoluble components block membranes and nozzles, increasing downtime.
Questions to ask:
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Are there material corrosion reports?
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Is there fouling data?
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Has material compatibility been tested?
Step 4: Evaluate Total Cost of Ownership (TCO)
Purchase price is only the first layer of cost.
Industrial chemicals carry three layers of cost:
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Visible cost: price/kg or price/ton
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Operational cost: efficiency, dosage, losses
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Risk cost: downtime, reprocessing, maintenance
Cheap chemicals are often only cheap in the first layer.
Hidden costs include:
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1–3% reduced reaction efficiency
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Increased energy consumption
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Accelerated equipment wear
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More frequent maintenance
Questions to ask:
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What is the actual consumption rate?
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What is the reaction conversion efficiency?
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Is scrap rate increasing?
4. Four-Step “COA Reading” Process for Technical Teams
To minimize risks, apply these four steps immediately upon receiving a COA draft:
Step 1: Match Batch Number and Date of Analysis
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Ensure batch numbers match COA, labels, and actual material.
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Date of analysis should be close to production date.
Step 2: Check Physical Properties
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Density/Specific Gravity: affects dosing pumps
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Viscosity: critical for polymers, resins, paint solvents
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Color: slight changes may indicate oxidation or metal contamination
Step 3: Analyze Impurity Profile
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Chloride & sulfate: may cause rapid electrochemical corrosion
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Heavy metals: critical for food, pharma, textiles for export
Step 4: Compare with Standard Specification
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Check both Result and Specification columns to see if the batch is at the upper or lower limit.
5. Signs of an Unreliable COA
Be cautious if a COA shows:
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Overly rounded numbers (e.g., all 0.00% or 99.00%)
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Missing QC/QA signatures or stamps
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Unclear test methods (e.g., “Internal Method” without ASTM, ISO, AOAC references)
Conclusion:
A COA is a tool, not a guarantee. Quick technical checks allow engineers and purchasing teams to catch risks before production, ensuring system stability, product quality, and cost optimization.
For expert consultation and accurate information on the chemical industry, KDCCHEMICAL provides fast and reliable support. Visit kdcchemical.vn or contact our hotline at +84 867 883 818.
