Introduction
In today's metalworking industry, the quality of processes such as electroplating, anodizing, pickling and surface treatment depends directly on the purity and specification of the chemical inputs used. As a result, the technical documentation that accompanies each batch of raw material has become as critical as the product itself.
Among the essential documents supplied by chemical distributors and manufacturers, the Certificate of Analysis (COA) sits at the center of quality assurance, batch traceability and compliance with quality management standards such as ISO 9001:2015 and IATF 16949:2016 (automotive sector).
This article covers the role of the COA in the metalworking industry: its structure, typical parameters, practical use in quality management systems and the criteria for qualifying chemical input suppliers. By the end, you will understand why serious metalworking plants demand a batch-specific COA and how to use this document to ensure compliance, traceability and predictable production processes.
1. What a Certificate of Analysis (COA) Is and Why It Is Essential in Metalworking
1.1 Definition and Purpose of the COA
The Certificate of Analysis (COA) is a technical document issued by the manufacturer or distributor of a chemical input that certifies the specific physicochemical characteristics of a batch of product. Unlike the Safety Data Sheet (SDS), which provides general information on hazards and handling, the COA records the results of actual laboratory analyses performed on the specific batch being supplied.
Typical elements of a COA:
- Batch identification: Unique traceability number
- Manufacturing and expiry dates: Shelf-life control
- Parameters analyzed: Purity, contaminants, density, pH, etc.
- Test methods: Technical standards used (ASTM, ABNT (the Brazilian Association of Technical Standards), pharmacopoeia)
- Results vs. specification: Comparison with acceptance limits
- Technical lead: Identification of the chemist responsible for the analyses
- Signature and stamp: Document authenticity
1.2 Why the COA Is Critical in Metalworking Processes
Metalworking processes such as jewelry and fashion jewelry electroplating, aluminum anodizing, decorative chrome plating, electropolishing and acid pickling run under extremely tight chemical composition controls. Minimal variations in the purity of acids, metal salts or alkalis can cause:
Quality Problems:
- Surface staining in electroplating (metallic contaminants)
- Pitting and premature corrosion in anodizing (residual chlorides)
- Discoloration of plating baths (organic impurities)
- Coating thickness variation (concentration out of specification)
- Rejection at visual inspection (uneven finish)
Compliance Problems:
- Nonconformities in ISO 9001 audits (no incoming material traceability)
- Failed IATF 16949 audits (automotive sector, where traceability is mandatory)
- Difficulty recalling batches (raw material cannot be traced)
- Loss of certifications (supplier requirements not met)
Economic Problems:
- Part rework (labor and material costs)
- Disposal of contaminated baths (loss of high-value raw materials)
- Production stoppages for analysis and correction
- Customer returns and loss of credibility
The COA acts as the first line of defense against these problems, allowing metalworking plants to confirm that each batch of input conforms before using it in production.
1.3 The COA as Objective Evidence in Quality Management Systems
Standards such as ISO 9001:2015 (clause 8.4, Control of externally provided processes, products and services) and IATF 16949:2016 require metalworking organizations to:
- Establish acceptance criteria for purchased raw materials
- Verify the conformity of externally provided products
- Keep records that demonstrate the requirements were met
The batch-specific COA is the objective evidence that satisfies these requirements. During internal or certification audits, COAs filed by batch demonstrate effective control over the supply chain and complete traceability.
2. Typical Parameters in COAs for Metalworking Chemical Inputs
📝 Important Note: The technical specifications shown in the following tables are illustrative examples based on typical chemical industry standards, provided for educational purposes. The actual specifications of products supplied by Boreto & Cardoso® are transcribed from the certificates issued by the approved manufacturers and may vary depending on the supplier of each batch. For the exact specifications of the products we supply, refer to the batch-specific COAs or contact our sales team.
2.1 COAs for Acids (Sulfuric, Hydrochloric, Nitric, Phosphoric)
Acids are the basis of pickling, chemical cleaning, surface activation and acid electrolytes in electroplating. The most common parameters in acid COAs include:
Sulfuric Acid (H₂SO₄)
| Parameter | Typical Specification | Test Method |
|---|---|---|
| Purity (% w/w) | 95.0 to 98.0% | Titration |
| Residue on evaporation | Max. 0.02% | Gravimetry |
| Chlorides (as Cl) | Max. 5 ppm | Argentometry |
| Iron (Fe) | Max. 10 ppm | Colorimetry |
| Heavy metals (as Pb) | Max. 5 ppm | Colorimetry |
| Arsenic (As) | Max. 0.1 ppm | Spectrophotometry |
| Appearance | Colorless liquid | Visual |
| Density at 20°C (g/cm³) | 1.83 to 1.84 | Hydrometer |
| Oxidizing substances (as O) | Max. 0.01% | Titration |
Why these parameters matter:
- Purity: The actual H₂SO₄ concentration affects pickling rate and bath pH
- Chlorides: Cause localized corrosion (pitting) in stainless steel and aluminum
- Iron: Contaminates plating baths (stains on parts)
- Heavy metals: Affect the quality of electroplated coatings (adhesion, brightness)
Hydrochloric Acid (HCl)
| Parameter | Typical Specification | Test Method |
|---|---|---|
| Purity (% w/w) | >32% | Titration |
| Residue on evaporation | Max. 0.005% | Gravimetry |
| Sulfates (as SO₄) | Max. 10 ppm | Turbidimetry |
| Iron (Fe) | Max. 5 ppm | Colorimetry |
| Heavy metals (as Pb) | Max. 1 ppm | Colorimetry |
| Appearance | Colorless liquid | Visual |
| Density at 20°C (g/cm³) | 1.16 to 1.17 | Hydrometer |
Critical applications: Pickling of carbon steel, surface activation before galvanizing, pH adjustment in acid baths.
2.2 COAs for Metal Salts (Copper Sulfate, Nickel Sulfate, Zinc Chloride)
Metal salts are the source of metal ions in electrodeposition (electroplating). Purity and the absence of contaminants are critical to the quality of the deposited coatings.
Copper Sulfate Pentahydrate (CuSO₄·5H₂O)
| Parameter | Typical Specification | Test Method |
|---|---|---|
| Purity (CuSO₄·5H₂O) | Min. 98.5% | Titration (EDTA) |
| Copper (Cu) | 25.0 to 25.5% | Titration |
| Iron (Fe) | Max. 20 ppm | Spectrophotometry |
| Nickel (Ni) | Max. 10 ppm | Spectrophotometry |
| Lead (Pb) | Max. 10 ppm | Spectrophotometry |
| Arsenic (As) | Max. 5 ppm | Spectrophotometry |
| Chlorides (Cl) | Max. 50 ppm | Argentometry |
| Water insolubles | Max. 0.02% | Gravimetry |
| pH (5% solution) | 3.5 to 4.5 | pH meter |
| Appearance | Blue crystals | Visual |
| Particle size | As per application | Particle size analysis |
Why these parameters matter:
- Purity: Affects the actual Cu²⁺ ion concentration in the bath (thickness control)
- Iron and Nickel: Co-deposit with copper (dark stains, loss of brightness)
- Chlorides: Cause pitting and corrosion in deposited coatings
- Insolubles: Cause roughness and surface defects
Nickel Sulfate Hexahydrate (NiSO₄·6H₂O)
| Parameter | Typical Specification | Test Method |
|---|---|---|
| Purity (NiSO₄·6H₂O) | Min. 98.0% | Titration (EDTA) |
| Nickel (Ni) | 22.0 to 22.5% | Titration |
| Cobalt (Co) | Max. 50 ppm | Spectrophotometry |
| Iron (Fe) | Max. 20 ppm | Spectrophotometry |
| Copper (Cu) | Max. 10 ppm | Spectrophotometry |
| Chlorides (Cl) | Max. 50 ppm | Argentometry |
| Water insolubles | Max. 0.01% | Gravimetry |
| pH (5% solution) | 4.0 to 5.5 | pH meter |
| Appearance | Green crystals | Visual |
| Heavy metals (as Pb) | Max. 5 ppm | Colorimetry |
Critical applications: Bright nickel plating, semi-bright nickel plating, electroless nickel plating, Watts baths.
2.3 COAs for Alkalis (Sodium Hydroxide, Sodium Carbonate)
Alkalis are used in alkaline cleaning (degreasing), neutralization of acidic wastewater and pH adjustment in alkaline plating baths.
Sodium Hydroxide (NaOH), Caustic Soda
| Parameter | Typical Specification | Test Method |
|---|---|---|
| Purity (NaOH) | Min. 98.0% | Titration |
| Sodium carbonate | Max. 1.0% | Titration |
| Chlorides (as NaCl) | Max. 0.05% | Argentometry |
| Sulfates (as SO₄) | Max. 0.05% | Turbidimetry |
| Iron (Fe) | Max. 10 ppm | Colorimetry |
| Heavy metals (as Pb) | Max. 5 ppm | Colorimetry |
| Mercury (Hg) | Max. 0.1 ppm | Atomic absorption |
| Appearance (flakes/pearls) | White solid | Visual |
Why these parameters matter:
- Purity: Affects the final pH of degreasing baths (cleaning efficiency)
- Carbonate: Reduces degreasing efficiency and causes precipitation
- Chlorides: Corrosion in stainless steel tanks
- Heavy metals: Contamination of alkaline zinc plating baths
2.4 COAs for Specialty Products (Lacquers, Sealants, Additives)
Products such as temporary protection lacquers, anodizing sealants, leveling additives and brighteners come with COAs that list application-specific parameters:
Example: Technical Lacquer for Electroplating
| Parameter | Typical Specification | Test Method |
|---|---|---|
| Solids content (%) | 18.0 to 22.0% | Gravimetry |
| Viscosity (cP) | 10 to 15 cP at 25°C | Viscometer |
| Density (g/cm³) | 0.88 to 0.92 | Hydrometer |
| pH | 6.5 to 8.0 | pH meter |
| Drying time | Max. 30 min at 25°C | Application test |
| Color | Colorless to slightly | Visual |
| Adhesion | Pass | Pull-off test |
| Bath resistance | No attack in 60 min | Immersion test |
| Appearance | Homogeneous liquid | Visual |
| Solubility | Soluble in acetone | Solubility test |
| Shelf life | 12 months | Accelerated stability |
3. Batch Traceability: Why It Is Critical in Surface Treatment
3.1 The Concept of Traceability in the Metalworking Supply Chain
Traceability is the ability to identify and follow the history, location and use of a product or raw material throughout the supply chain. In the metalworking industry, traceability means:
- Backward traceability: Identifying the supplier, batch and date of every chemical input used
- Internal traceability: Recording in which process, bath and period each input batch was used
- Forward traceability: Linking input batches to the finished product batches delivered to customers
The batch number on the COA is the key element that makes this complete traceability possible.
3.2 Traceability in Nonconformity Situations
Real-world scenario: A manufacturer of automotive components finds recurring staining on chrome-plated parts produced during a certain period. Without input batch traceability, the investigation would be extremely difficult:
- Which batch of chromic acid was used?
- Which batch of activation sulfuric acid was used?
- Which batch of base nickel was used?
- When were these batches received and used?
With COAs filed by batch and consumption records:
- The production period of the affected parts is identified
- The input consumption record for that period is checked
- The batch COAs used during that period are retrieved
- The COA parameters are compared with internal specifications
- A batch of sulfuric acid with high iron is found (15 ppm vs. a 10 ppm limit)
- Root cause confirmed: Iron contamination in the activation bath caused co-deposition and staining
- Corrective action: Discard the remaining stock of the problem batch, tighten the purchase specification to iron < 5 ppm, audit the supplier
Investigation time: 4 hours (with traceability) vs. weeks of trial and error (without traceability)
3.3 Traceability and Batch Recalls
In serious cases of nonconformity (electroplated coating adhesion failure, premature corrosion, chemical contamination), a recall of finished products already delivered to customers may be necessary.
Example: Automotive industry (IATF 16949)
A supplier of chrome-plated parts detects chrome layer delamination on components supplied to an automaker. The automaker requires:
- Identification of all potentially affected batches
- Tracing of when and for which vehicles the parts were supplied
- Evidence of the input batch used in the affected production
With filed COAs and an internal traceability system:
- The problem is traced to parts produced with chromic acid batch L2025-0345
- The COA for batch L2025-0345 shows an organic contaminant above specification
- The ERP system shows this batch was used exclusively from March 15 to March 22
- Parts produced in that period went to 3 specific vehicle models
- A targeted recall avoids the unnecessary recall of thousands of vehicles
Cost avoided: Millions of reais in a broader recall
3.4 Traceability Requirements in ISO 9001 and IATF 16949
ISO 9001:2015, Clause 8.5.2 (Identification and Traceability):
"The organization shall control the unique identification of the outputs when traceability is a requirement, and shall retain the documented information necessary to enable traceability."
IATF 16949:2016, Additional requirements:
- Raw material batch traceability is mandatory throughout the automotive chain
- COAs must be kept for a minimum period defined by the customer (typically 15 years)
- Traceability records must allow identification in both directions (from supplier to customer and back)
Practical implication: Metalworking plants that supply the automotive sector cannot accept inputs without a batch-specific COA. Suppliers that do not provide COAs are automatically disqualified.
4. Transcribed COA vs. In-House Analysis: The Distributor's Role
4.1 COA Issuance Models in the Distribution Chain
There are two main models for COA issuance by chemical input distributors:
Model 1: Transcribed COA (most common in distribution)
- The distributor receives the manufacturer's original COA
- The distributor transcribes the data onto its own standardized form
- The manufacturer's batch number is kept (traceability preserved)
- The distributor does not perform its own analyses
- Confidence is based on manufacturer qualification and audits
Model 2: COA with In-House Analysis (less common, higher cost)
- The distributor has its own certified laboratory
- It performs independent analyses on every batch received
- It issues a COA with its own results
- Higher operating cost (passed on to the price)
- More common for critical products or large distributors
4.2 Why the Transcribed Model Is Widely Used
The transcribed COA model is standard practice in chemical distribution for solid technical and commercial reasons:
1. Traceability Back to the Original Manufacturer
Transcribing the manufacturer's COA preserves traceability back to the product's origin. In case of nonconformity, the manufacturer can be audited directly and the original production records checked.
2. Protecting the Supply Source
Distributors often protect their supply sources (approved manufacturers) by transcribing data onto their own form. This prevents customers from negotiating directly with manufacturers and preserves the business model.
3. Cost-Benefit
Maintaining an in-house laboratory to analyze hundreds of batches a month is economically unfeasible for most distributors. The cost would be passed on to the customer, making products less competitive.
4. Confidence in Certified Manufacturers
Serious distributors qualify manufacturers based on:
- ISO 9001, ISO 14001 and ISO 45001 certifications
- On-site audits at the manufacturer's facilities
- Compliance history (nonconformity records)
- Technical capability (accredited laboratory, validated methods)
This qualification carries confidence over to the manufacturer's analyses.
4.3 Parameter Variations Between Approved Suppliers
A key point raised by experienced chemistry professionals is that there is no complete uniformity in the technical specifications of the same product across different manufacturers.
Real example: Copper Sulfate Pentahydrate
Manufacturer A (approved):
- Parameters analyzed: Purity, Cu, Fe, Ni, Pb, Chlorides, Insolubles, pH
- Fe method: UV-Vis spectrophotometry
- Fe limit: Max. 20 ppm
Manufacturer B (approved):
- Parameters analyzed: Purity, Cu, Fe, Ni, Zn, As, Chlorides, Sulfates, Insolubles
- Fe method: ICP-OES
- Fe limit: Max. 15 ppm
Practical implication:
- Both manufacturers conform to their own specifications
- Both are suitable for use in electroplating
- The distributor may supply product from either manufacturer depending on availability
- The transcribed COA will reflect the specification of the manufacturer actually supplied
This flexibility is normal and acceptable in the chemical industry, provided that:
- All approved manufacturers are audited and approved
- Products from every manufacturer meet the minimum application requirements
- The customer is informed of possible variations between batches from different sources
4.4 The Distributor's Legal Responsibility for a Transcribed COA
Even when transcribing the manufacturer's data, the distributor takes on legal responsibility for the COA it issues. For this reason, transcription requires:
Mandatory Controls:
- Integrity check: Sealed packaging with no signs of tampering
- Batch check: Batch number on the packaging = batch number on the original COA
- Filing of the original COA: Keep the manufacturer's COA on file for audits
- Clear identification: The transcribed COA must state that the data come from the original manufacturer
- Complete traceability: Records that identify the origin of each batch
Typical clause in a transcribed COA:
"The technical specifications and analytical results presented in this document are transcribed from information provided by the original manufacturer. [Distributor Name] keeps records of the original test reports for traceability and audit purposes."
This transparency is ethically and legally sound, preserving traceability without creating the expectation of independent analyses.
5. How to Use the COA for Incoming Material Inspection
5.1 COA-Based Receiving Inspection (ISO 9001 Clause 8.6)
ISO 9001:2015, clause 8.6 (Release of products and services) requires organizations to verify that externally provided products meet requirements before releasing them for use.
Typical receiving inspection procedure for chemical inputs:
Step 1: Document Check (100% of batches)
- ✅ Does a COA accompany the product?
- ✅ Batch number on the COA = batch number on the packaging?
- ✅ Manufacturing date within shelf life?
- ✅ Were all critical parameters analyzed?
- ✅ Are the results within the purchase specification?
- ✅ Is the COA signed by a technical lead?
- ✅ Is the supplier approved?
Step 2: Physical Check (100% of batches)
- ✅ Packaging intact, with no leaks or tampering?
- ✅ Security seal intact?
- ✅ Labeling compliant with ABNT NBR 14725-3 (Brazilian technical standard for GHS hazard communication)?
- ✅ Quantity received = quantity ordered?
- ✅ Visual appearance consistent with the product (color, physical state)?
Step 3: Analytical Check (sampling based on criticality)
Depending on the criticality of the input and the supplier's history, metalworking plants may run verification analyses:
- Critical products (high frequency): Purity analysis, critical contaminants (e.g. Fe in acids)
- Non-critical products (low frequency): Density and pH checks (simple analyses)
- Poor supplier history: Increased verification frequency
Inspection outcome:
- APPROVED: Batch released for production
- APPROVED WITH RESTRICTIONS: Released for less critical processes
- ON HOLD: Awaiting verification analysis or clarification from the supplier
- REJECTED: Returned to the supplier, nonconformity opened
5.2 Acceptance Criteria Based on the Purchase Specification
The internal purchase specification should define acceptance criteria for each COA parameter:
Example: Purchase Specification, Sulfuric Acid for Pickling
| Parameter | Supplier Specification | Internal Acceptance Criterion | Rationale |
|---|---|---|---|
| Purity (%) | 95.0 to 98.0% | 96.0 to 98.0% | Pickling rate control |
| Iron (ppm) | Max. 10 ppm | Max. 5 ppm | Avoid bath contamination |
| Chlorides (ppm) | Max. 5 ppm | Max. 5 ppm | Same as supplier |
| Density (g/cm³) | 1.83 to 1.84 | 1.83 to 1.84 | Same as supplier |
| Residue on evaporation | Max. 0.02% | Max. 0.01% | Tighter control (critical process) |
| Heavy metals (ppm) | Max. 5 ppm | Max. 3 ppm | End-customer requirement (export) |
Note: Internal criteria may be stricter than the supplier's specification when the process requires tighter control.
5.3 Recording and Filing COAs for Traceability
Filing requirements under ISO 9001 and IATF 16949:
Filing format:
- Physical: Files organized by supplier, then by product, then by receiving date
- Digital: Quality management system (QMS) with automatic backup
- Indexing: Batch number, receiving date, invoice number
Minimum retention period:
- ISO 9001 (general): Product life cycle plus warranty period
- IATF 16949 (automotive): Minimum of 15 years after last production
- Pharmaceutical, aerospace: Up to 30 years or permanent
COA-related information that should be filed:
- ✅ Original COA (PDF or paper)
- ✅ Purchase invoice
- ✅ Receiving inspection certificate
- ✅ Verification analysis results (if performed)
- ✅ Batch release or rejection record
- ✅ Batch consumption record (which processes it was used in)
5.4 Integrating the COA into the Quality Management System (QMS)
Integrated flow linking the COA, the QMS and traceability:
- Receiving: The COA is scanned and attached to the receiving record in the ERP/QMS
- Inspection: The inspection result is recorded in the QMS against the batch number
- Storage: A label with the batch number and status (approved/on hold/rejected) is attached to the packaging
- Requisition: When an input is requisitioned for production, the batch number is recorded on the production order
- Consumption: The system tracks how much of each batch was consumed in each production order
- Traceability: In case of nonconformity, the system identifies which finished products were affected
Benefits of integration:
- ✅ Automatic traceability (no reliance on manual records)
- ✅ Batch expiry alerts (prevents use of expired products)
- ✅ Consumption reports by batch (supplier performance analysis)
- ✅ Objective evidence for audits (ISO 9001, IATF 16949)
6. COA Requirements in ISO 9001 and IATF 16949
6.1 ISO 9001:2015, Control of Externally Provided Processes, Products and Services
Clause 8.4.1 (General):
"The organization shall ensure that externally provided processes, products and services conform to requirements. The organization shall determine the controls to be applied to externally provided processes, products and services when: a) products and services from external providers are intended for incorporation into the organization's own products and services."
Implication for the COA:
Chemical inputs are incorporated into metalworking processes (baths, treatments). Therefore, control through the COA is mandatory.
Clause 8.4.3 (Information for external providers):
"The organization shall communicate to external providers its requirements for: a) the processes, products and services to be provided; b) the approval of products and services, methods, processes and equipment; c) the release of products and services."
Implication for the COA:
The purchase specification must formally require the supplier to deliver a COA with defined parameters.
Objective evidence in ISO 9001 audits:
- ✅ Documented purchase specifications (with a COA requirement)
- ✅ Filed COAs for received batches
- ✅ COA-based receiving inspection records
- ✅ Records of corrective actions with suppliers (when a COA shows nonconformity)
6.2 IATF 16949:2016, Specific Requirements for the Automotive Sector
IATF 16949 is stricter than ISO 9001, especially regarding traceability and supplier control.
Requirement 8.4.2.3.1 (Supplier Quality Management System Development):
"The organization shall carry out supplier quality management system development with the goal of conformity with IATF 16949. Conformity with ISO 9001 by an automotive product supplier may be considered the first step toward achieving this goal."
Implication for the COA:
Chemical input suppliers to automotive metalworking plants must hold at least ISO 9001. COAs must reflect certified quality control.
Requirement 8.5.1.2 (Control Plan):
"The organization shall: a) have control plan(s) at the relevant levels for product manufacturing; b) review and update the control plan whenever any change occurs that affects the product, manufacturing process, measurement, logistics, supply sources or FMEA."
Implication for the COA:
A change of supplier or chemical input batch may require a control plan review if it affects a critical characteristic of the final product.
Requirement 8.5.2.1 (Identification and Traceability, Supplemental):
"The organization shall maintain a documented procedure that defines the traceability system. Traceability records shall be kept for the product's service life plus one calendar year, unless otherwise specified by regulatory or customer requirements."
Implication for the COA:
COAs must be kept for at least 15 years at automotive metalworking plants.
6.3 Second-Party Audits: What Customers Check in COAs
Customers of metalworking plants (especially in the automotive, aerospace and oil and gas sectors) often carry out second-party audits of their suppliers. COA-related items checked:
Typical audit checklist:
- ✅ Purchase specifications: Do all critical inputs have a formal specification?
- ✅ COA requirement: Does the specification require a batch-specific COA?
- ✅ Filing: Are COAs filed in an organized, traceable way?
- ✅ Receiving inspection: Is there a record of the COA conformity check?
- ✅ Traceability: Can you trace which input batch a given finished product batch came from?
- ✅ Nonconformities: Are there records of rejected or restricted batches? Were corrective actions taken with the supplier?
- ✅ Shelf life: Does the system flag batches close to expiry?
- ✅ Supplier qualification: Are suppliers audited/qualified? Is there a formal criterion?
Common nonconformities found:
- ❌ COAs not filed, or filed in a disorganized way
- ❌ Batches used without a COA (supplier did not deliver it)
- ❌ Receiving inspection does not check COA parameters
- ❌ Broken traceability (impossible to tell which input batch went into which finished product)
7. The Boreto & Cardoso® Difference: Batch-Specific COA and 53 Years of Trust
7.1 Commitment to Full Traceability
Boreto & Cardoso®, with 53 years of experience supplying specialty chemical inputs to the metalworking industry, understands how critical traceability is in electroplating, anodizing, pickling and surface treatment processes.
Supply practices that ensure traceability:
1. Batch-specific Certificate of Analysis
Every batch supplied comes with an individual COA, transcribed from the analyses performed by the original manufacturer. We do not use generic or outdated COAs.
2. Clear batch identification on packaging
All packaging (drums, jerrycans, bags, bottles) is labeled with:
- ✅ Manufacturer's batch number
- ✅ Manufacturing and expiry dates
- ✅ Boreto & Cardoso® invoice number
- ✅ Product code (Boreto internal)
This identification lets the customer match the COA to the physical package without ambiguity.
3. Organized archive of the manufacturers' original COAs
We keep on file the original COAs issued by the manufacturers for every batch supplied. In the event of a customer audit or a nonconformity investigation, these original documents are available for review, preserving traceability back to the source.
4. Approved and audited suppliers
We work exclusively with approved manufacturers that have:
- ✅ ISO 9001:2015 certification (quality management)
- ✅ Laboratories with validated test methods
- ✅ A track record of compliance and reliability
- ✅ Capacity for continuous supply
This qualification ensures that transcribed COAs reflect reliable, traceable analyses.
7.2 Specialized Portfolio for the Metalworking Industry
39 specialized products covering the different stages of metalworking processes:
Acids for Pickling and Activation:
- Sulfuric Acid (98%)
- Hydrochloric Acid (32%)
- Nitric Acid (53%)
- Phosphoric Acid (85%)
Metal Salts for Electrodeposition:
- Copper Sulfate Pentahydrate
- Nickel Sulfate Hexahydrate
- Zinc Chloride
- Zinc Sulfate
- Chromium Salts (subject to regulations)
Alkalis for Cleaning and Neutralization:
- Sodium Hydroxide (flakes/pearls/solution)
- Sodium Carbonate (light/dense soda ash)
- Sodium Tripolyphosphate
Specialty Products:
- Technical lacquers for temporary protection
- Anodizing sealants
- Leveling additives and brighteners
All products come with:
- ✅ Batch-specific Certificate of Analysis (COA)
- ✅ Safety Data Sheet (SDS) updated in accordance with ABNT NBR 14725-4
- ✅ Batch and expiry identification on the packaging
- ✅ Invoice with full traceability
7.3 Qualified Technical Service (Not Consulting)
It is worth clarifying the role of Boreto & Cardoso® in the metalworking industry value chain:
What we do:
- ✅ Supply chemical inputs with complete technical documentation (COA, SDS)
- ✅ Provide information on technical specifications, storage and safe handling as per the SDS
- ✅ Answer questions about COA parameters and documentary compliance
- ✅ Specialized sales service with technical knowledge of the portfolio
What we do NOT do:
- ❌ Develop electroplating or anodizing processes
- ❌ Technical consulting to solve problems in baths or treatments
- ❌ Independent laboratory analysis of products (COAs are transcribed from approved manufacturers)
- ❌ Formulate baths or custom technical specifications
This clear positioning upholds professional ethics and avoids creating expectations for services we do not offer. Our value lies in supplying reliable products with complete technical documentation, so that metalworking plants can maintain traceability and compliance with quality management standards.
7.4 ISO 9001:2015 Certification and Commitment to Quality
Boreto & Cardoso® is ISO 9001:2015 certified for the supply of industrial chemical inputs. This certification ensures that our processes for:
- Supplier selection and qualification
- Receiving inspection of products
- Storage and preservation of chemical products
- Batch identification and traceability
- Shipping and delivery of products
...are controlled, documented and audited by an independent certification body.
Practical implication for customers:
By choosing Boreto & Cardoso® as a supplier, metalworking plants certified to ISO 9001 or IATF 16949 can rely on the conformity of our supply processes, reducing the need for second-party audits and making it easier to pass third-party audits.
7.5 Logistics and Supply Flexibility
Delivery scheduling that supports inventory control and traceability:
- ✅ Scheduled automatic replenishment (reduces the risk of using expired batches)
- ✅ JIT (Just-in-Time) deliveries for high-volume customers
- ✅ Flexible packaging (from 1 L bottles to 1,000 L IBC containers)
- ✅ Products available for immediate delivery (local stock)
8. Frequently Asked Questions (FAQ)
8.1 Are all chemical input suppliers required to provide a COA?
There is no legal obligation to provide a COA for every type of chemical product. However, quality management standards such as ISO 9001 and IATF 16949 require organizations to set acceptance criteria for externally provided products. In practice, this means certified metalworking plants must require a COA in their purchase specifications.
Serious industrial chemical suppliers provide a COA as standard practice, because they know certified customers require it.
8.2 Does a transcribed COA carry the same legal weight as a COA based on the distributor's own analyses?
Yes, provided that:
- The distributor clearly states that the data are transcribed from the original manufacturer
- The distributor keeps on file the manufacturer's original COAs for traceability
- The original manufacturer is qualified and audited by the distributor
The transcribed COA model is standard practice in chemical distribution and is accepted in ISO 9001 and IATF 16949 audits, as long as there is traceability back to the manufacturer.
8.3 How can I check whether a COA is authentic?
Recommended checks:
- ✅ Does the COA identify the technical lead (name, CRQ registration with Brazil's Regional Chemistry Council, signature)?
- ✅ Is there a stamp or watermark from the issuing company?
- ✅ Does the batch number on the COA match the batch number on the packaging?
- ✅ Are the test methods identified (ASTM, ABNT, pharmacopoeia)?
- ✅ Is the issue date consistent with the manufacturing date?
- ✅ Are the issuing company's logo and contact details present?
If in doubt, contact the supplier directly and ask for confirmation of authenticity via corporate email.
8.4 How long should I keep COAs for chemical inputs?
It depends on the sector and the applicable standards:
- ISO 9001 (general): Service life of the final product plus the warranty period offered to customers
- IATF 16949 (automotive): At least 15 years after the product's last production
- Pharmaceutical, medical devices: Up to 30 years or permanent
- Aerospace, defense: Often permanent
Check your customers' contractual requirements and the regulatory requirements of your sector.
8.5 What should I do if a batch arrives without a COA?
Recommended procedure:
- Hold the batch (do not release it for production)
- Contact the supplier immediately and request the COA
- Record a nonconformity in the quality management system
- Set a deadline for the COA to be sent (e.g. 48 business hours)
- If the COA is not sent by the deadline: return the batch to the supplier and consider disqualifying the supplier
Never use chemical inputs in production without a COA, especially if your plant is certified to ISO 9001 or IATF 16949. The risk of an audit nonconformity and loss of traceability is too high.
8.6 Can I accept a generic (non-batch-specific) COA?
It is not recommended. A generic COA (one that does not identify a specific batch) does not meet the traceability requirements of ISO 9001 and IATF 16949.
A generic COA may be acceptable only for:
- Very low criticality products (e.g. auxiliary materials that do not come into contact with the final product)
- Suppliers under development (temporarily, with a deadline to comply)
For all critical inputs (acids, metal salts, alkalis used in metalworking processes), require a batch-specific COA.
8.7 Do the differences between a COA and a test report matter?
COA (Certificate of Analysis) and test report are often used as synonyms in the chemical industry, but there are conceptual differences:
COA (Certificate of Analysis):
- A document that certifies the conformity of a specific batch with a specification
- Issued routinely for each batch produced
- Focused on quality parameters (purity, contaminants, physicochemical properties)
Test Report:
- A broader document that may include special analyses or additional tests
- Not always batch-specific (may refer to the product in general)
- May include performance test results (not only chemical analysis)
In practice, for traceability and ISO 9001 compliance, what matters is that the document:
- Identifies a specific batch
- Presents the results of analyses performed on that batch
- Is issued by a reliable laboratory (manufacturer or certified laboratory)
The name (COA or test report) matters less than the content and traceability.
9. Conclusion
In the metalworking industry, the Certificate of Analysis (COA) is much more than a routine technical document: it is the essential link between the quality of the chemical inputs supplied and the predictability, compliance and traceability of production processes.
Metalworking plants that operate with technical rigor, especially those certified to ISO 9001:2015 or IATF 16949:2016, understand that there is no effective quality control without raw material batch traceability. And there is no traceability without a batch-specific COA.
In this article, we covered:
- The role of the COA as objective evidence of conformity
- Typical parameters in COAs for acids, metal salts and alkalis used in metalworking
- How critical traceability is in nonconformity and recall situations
- The difference between transcribed COAs and in-house analyses (and why the former is widely used)
- How to integrate the COA into receiving inspection procedures and quality management systems
- Specific requirements of ISO 9001 and IATF 16949
For metalworking plants looking for reliable suppliers, a batch-specific COA, provided consistently and with full traceability, is a fundamental qualification criterion.
Boreto & Cardoso®, with 53 years of experience supplying specialty chemical inputs to the metalworking industry, bases its work on three pillars:
- Certified products with complete technical documentation (COA + SDS)
- Full traceability from manufacturer to end customer
- Commitment to compliance (ISO 9001:2015 certification)
We do not promise to solve technical process problems: that is the responsibility of each plant's technical team. Our role is to supply reliable inputs with documentation that enables traceability, incoming inspection and compliance with quality management standards.
Serious companies choose serious suppliers. And serious suppliers provide a batch-specific COA, without exception.
Note to the Reader
This article is purely informational and educational, covering the importance of the Certificate of Analysis (COA) in the metalworking industry and the traceability requirements of ISO 9001 and IATF 16949.
Boreto & Cardoso® operates exclusively as a distributor of industrial chemical inputs, supplying products with complete technical documentation (Certificate of Analysis and Safety Data Sheet). We do not perform independent laboratory analyses: our COAs are faithful transcriptions of the analyses performed by approved manufacturers, preserving traceability back to the source.
We do not offer:
- Technical consulting for the development of electroplating, anodizing or surface treatment processes
- Troubleshooting of baths or metalworking processes
- Bath formulation or custom technical specifications
- Laboratory analysis of products or wastewater
For technical questions about using products in specific processes, we recommend consulting professionals specialized in metallurgical or chemical engineering.
Contact information for questions about products and technical documentation:
📧 Email: boreto@boreto.com.br
📞 Phone:
- Head Office (SP): +55 (11) 3931-1722 | +55 (11) 2366-6260
- Head Office WhatsApp: +55 (11) 99108-2229 | +55 (11) 94541-0088 | +55 (11) 91311-3528 | +55 (19) 97685-0233
- Limeira Branch: +55 (19) 99458-6331
- Branch WhatsApp: +55 (19) 99557-1693
📍 Addresses:
- Head Office: R. Alagoas, 30, Recanto Silvestre, Santana de Parnaíba, SP, 06530-245
- Branch: R. Aratibá, 759, Centro Industrial de Limeira (CIL), Limeira, SP, 13481-208
🕐 Business Hours: Monday to Friday, 8:00 a.m. to 12:00 p.m. and 1:15 p.m. to 5:30 p.m.
Boreto & Cardoso®: 53 years supplying chemical inputs with quality, traceability and commitment.