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Conductivity Standards | NIST Traceability | Low-Conductivity Calibration | Measurement Uncertainty | Laboratory Quality Assurance
RICCA 2236.02-16 Sodium Chloride Conductivity Standard: Calibration, NIST Traceability & Low-Conductivity Measurement Guide
RICCA Chemical Company 2236.02-16 (R2236020-500A) is a prepared sodium chloride conductivity reference solution with a nominal conductivity of 5 µS/cm at 25°C. Supplied in a 500 mL natural polyethylene bottle, the standard supports conductivity instrument calibration, verification, and analytical laboratory quality-control workflows.
RICCA publishes a conductivity specification of 4.95-5.05 µS/cm at 25°C and an expanded measurement uncertainty of 0.26 µS/cm (k=2). The manufacturer's specification identifies NIST Standard Reference Material 999 and documents testing performed under ISO/IEC 17025 laboratory accreditation.
Technical Takeaway: A 5 µS/cm conductivity standard requires careful temperature control, instrument selection, contamination prevention, and handling. The manufacturer's conductivity specification, uncertainty statement, and NIST traceability must be interpreted together when qualifying the solution for a specific calibration or verification procedure.
1. Understanding Electrical Conductivity
Electrical conductivity describes the ability of a solution to carry electrical current through dissolved ions. In aqueous sodium chloride solutions, sodium ions (Na+) and chloride ions (Cl-) contribute to electrical charge transport.
Conductivity is commonly expressed in microsiemens per centimeter (µS/cm). The historical unit micromho per centimeter (µmho/cm) is numerically equivalent to µS/cm.
Low-conductivity measurement is particularly sensitive to dissolved contamination, temperature changes, cell condition, and the measurement environment. These factors may become significant relative to the target reading when evaluating a 5 µS/cm standard.
Measurement Principle: Conductivity is not equivalent to pH. The standard's 5 µS/cm designation describes electrical conductivity at its specified reference temperature, not hydrogen-ion concentration.
2. Verified Product Specifications
- Manufacturer: RICCA Chemical Company
- Product: Sodium Chloride Conductivity Standard
- RICCA Catalog Number: 2236.02-16
- Extended Manufacturer Part Number: R2236020-500A
- Manufacturer Product Number: 2236.02
- Nominal Conductivity: 5 µS/cm at 25°C
- Conductivity Acceptance Range: 4.95-5.05 µS/cm at 25°C
- Published Expanded Uncertainty: 0.26 µS/cm
- Coverage Factor: k=2
- Manufacturer Test Methods: SQCP031 and SQCP033
- NIST Reference Material: SRM 999
- Components: Water and sodium chloride
- Physical State: Liquid
- Appearance: Colorless
- SDS-Reported pH: 6.7-7.3
- Relative Density: 1.00
- Water Solubility: Miscible
- Bottle Material: Natural polyethylene
- Bottle Volume: 500 mL
- Purchase Quantity: One (1) bottle
- Unopened Shelf Life: 12 months
- Recommended Storage: 15-30°C (59-86°F)
- Recommended Use: General laboratory reagent
- GHS Classification: Not classified as hazardous
- DOT/IATA Classification: Not regulated
Specification Control: The published 4.95-5.05 µS/cm range describes the manufacturer specification. The actual certified conductivity value and associated lot information must be verified using documentation corresponding to the purchased manufacturing lot.
3. Chemical Composition and CAS Identification
RICCA's Product Number 2236.02 Safety Data Sheet identifies the following chemical components:
- Water: CAS 7732-18-5; listed as 100.00% by weight after rounding in the SDS
- Sodium Chloride: CAS 7647-14-5; less than 0.1% by weight
The manufacturer's Product Specification identifies the water as ACS/ASTM/USP/EP grade and the sodium chloride as ACS grade.
The dissolved sodium chloride contributes the mobile ions responsible for the solution's conductivity. Because the standard contains a very low dissolved-salt concentration, even small additional ionic contamination can affect measured results.
Composition Note: The SDS reports rounded ingredient percentages for safety communication. These values do not establish an exact gravimetric preparation recipe or provide the individual lot's certified conductivity measurement.
4. Certified Conductivity, Measurement Uncertainty and NIST Traceability
RICCA's published Product Specification identifies conductivity testing at 25°C using methods SQCP031 and SQCP033, with an acceptance range of 4.95-5.05 µS/cm.
The same document reports an expanded uncertainty of 0.26 µS/cm, calculated using a coverage factor of k=2. The manufacturer describes this as corresponding to approximately 95% coverage under a normal-distribution model.
- Nominal Reference Value: 5 µS/cm
- Specification Range: 4.95-5.05 µS/cm
- Published Expanded Uncertainty: 0.26 µS/cm
- Coverage Factor: k=2
- NIST Reference: SRM 999
- Measurement Methods: SQCP031 and SQCP033
- Reference Temperature: 25°C
Acceptance Range vs. Measurement Uncertainty: The 4.95-5.05 µS/cm product specification and the 0.26 µS/cm uncertainty are different quantities. The uncertainty should not be represented as the manufacturer's pass/fail tolerance or omitted from a measurement uncertainty assessment.
RICCA states that its conductivity measurements are performed under ISO/IEC 17025 laboratory accreditation and are traceable to NIST through an unbroken chain of comparisons.
Quality Qualification: Verify the actual lot certificate, its reported conductivity value, stated uncertainty, traceability information, and applicability to the laboratory's measurement requirements. A general Product Specification with a SAMPLE lot identifier is not a substitute for the actual lot-specific certificate.
5. Temperature Control and Conductivity Measurement
Conductivity depends on temperature because ionic mobility changes with the thermal conditions of a solution. RICCA defines the standard's conductivity at 25°C.
When measurement occurs at a different temperature, the instrument may display actual conductivity or a temperature-compensated value, depending on its configuration. The selected compensation model must be appropriate for the standard and approved measurement procedure.
- Use a conductivity instrument suitable for low-conductivity measurement.
- Verify the selected temperature mode before measurement.
- Allow the solution and sensor to reach the required thermal condition.
- Follow the instrument manufacturer's instructions for calibration and reference-temperature settings.
- Use the actual lot-certified value where the procedure requires it.
- Document temperature and measurement conditions where required.
Temperature Compensation Caution: A generic fixed percentage-per-degree correction should not automatically be assumed appropriate for every conductivity solution or instrument. Follow the validated procedure and relevant instrument documentation.
6. Conductivity Instrument Calibration and Verification
A conductivity standard is used to establish or check instrument response against a known reference. The specific calibration process depends on the instrument design, conductivity cell, operating range, and quality-system requirements.
- Confirm suitability: Verify that a 5 µS/cm reference is appropriate for the instrument and measurement range.
- Review documentation: Check the standard's identity, expiration date, and applicable lot-certified conductivity value.
- Prepare equipment: Inspect and condition the sensor according to the manufacturer's instructions.
- Control contamination: Use clean vessels and fresh standard solution.
- Control temperature: Use the required reference-temperature conditions or approved correction procedure.
- Perform measurement: Follow the instrument-specific calibration or verification sequence.
- Evaluate results: Compare readings against the approved instrument or laboratory acceptance criteria.
- Document: Record the standard lot, actual conductivity reference, observed measurement, and relevant instrument conditions.
Instrument Qualification: This standard provides a reference material. Successful calibration or verification still depends on the instrument's performance, measurement procedure, measurement uncertainty, and applicable acceptance limits.
7. Low-Conductivity Contamination Control
Low-conductivity reference solutions are sensitive to small contamination sources that may be insignificant when testing highly conductive samples.
Atmospheric carbon dioxide can dissolve in water and alter its ionic composition. Residues on measurement cells, inadequately cleaned containers, transferred salts, and sample carryover can also affect conductivity measurements.
- Use clean vessels: Select containers appropriate for low-ionic-contamination work.
- Minimize exposure: Keep the original bottle closed when not dispensing.
- Use fresh aliquots: Dispense only the amount needed for the procedure.
- Prevent carryover: Follow approved sensor cleaning and rinsing procedures.
- Avoid returning solution: Do not transfer used standard back into the stock bottle.
- Limit handling: Avoid unnecessary transfers or prolonged exposure to laboratory air.
- Maintain cell condition: Check for deposits, damage, bubbles, and other factors affecting instrument response.
Measurement Integrity: Contamination control is a measurement requirement, not merely a cleanliness preference. The lower the conductivity being measured, the more important small sources of additional ions may become.
8. Storage, Shelf Life and Stability
RICCA specifies a recommended storage temperature of 15-30°C (59-86°F) and a 12-month unopened shelf life for Product Number 2236.02, including the 500 mL natural polyethylene configuration.
The SDS directs users to protect the container from freezing and physical damage. The solution is described as stable under normal use and storage conditions.
- Storage Temperature: 15-30°C
- Original Container: Natural polyethylene bottle
- Container Closure: Keep closed when not dispensing
- Freezing: Protect from freezing
- Physical Protection: Avoid damage, leaks, and contamination
- Incompatibilities: Avoid materials identified as incompatible by the SDS
- Expiration: Follow manufacturer labeling and actual lot documentation
- In-Use Control: Follow laboratory procedures after opening
Shelf-Life Limitation: The 12-month published shelf life applies to unopened containers. It does not authorize 12 months of use after opening or supersede the actual expiration date assigned to the received lot.
9. Laboratory Applications and Method Compatibility
The 5 µS/cm sodium chloride standard can be considered for analytical procedures requiring a reference near this conductivity value, including laboratory water monitoring and conductivity meter performance verification.
Pharmaceutical laboratories may perform conductivity measurements using procedures governed by USP <645> or other applicable methods. Selection of a particular standard for instrument qualification must be consistent with the current method requirements.
- Confirm the required conductivity reference value.
- Verify the instrument's supported calibration standards and range.
- Determine applicable reference-temperature requirements.
- Review the actual lot-certified conductivity and uncertainty.
- Confirm that the reference is appropriate for the analytical method.
- Document instrument qualification and acceptance criteria.
Compendial Limitation: A NIST-traceable conductivity standard does not, by itself, establish compliance with USP <645> or any other analytical procedure. Compliance depends on all relevant instrument, calibration, method, and system requirements.
10. Safety and Transportation Classification
The referenced RICCA Product Number 2236.02 Safety Data Sheet identifies the sodium chloride conductivity standard as not classified as hazardous under GHS.
- GHS Classification: Not classified as hazardous
- GHS Signal Word: None required
- GHS Pictograms: None required
- DOT Transportation: Not regulated
- IATA Air Transportation: Not regulated
- Canadian TDG: Not regulated
- Eye Protection: Safety glasses or goggles
- Hand Protection: Chemical-resistant gloves
- Ventilation: Normal room ventilation is identified as adequate
Although the standard is not GHS-classified as hazardous, normal laboratory chemical hygiene remains necessary. Contact with the eyes or skin may cause irritation.
Safety Notice: Refer to the current manufacturer SDS for handling, emergency response, transportation, and disposal requirements. The reviewed SDS lists a revision date of September 16, 2024.
11. Quality Documentation and Audit Readiness
RICCA's published Product Specification identifies conductivity testing methods, certified-value criteria, expanded uncertainty, NIST traceability, and packaging information.
- Manufacturer Product Specification: Defines conductivity requirements, uncertainty, packaging, storage, and unopened shelf life.
- Lot-Specific Certificate: Identifies the actual tested lot and its reported conductivity result and supporting information.
- Safety Data Sheet: Provides composition, chemical safety, handling, and transportation information.
- NIST Traceability: Provides documented reference to the relevant standard and measurement chain.
- Measurement Uncertainty: Supports evaluation of the reference material's suitability for the intended measurement.
- Lot Traceability: Connects the material used with laboratory records.
- Expiration Control: Tracks the manufacturer-assigned expiration date and in-use restrictions.
- Instrument Qualification: Documents that the selected standard is appropriate for the applicable procedure.
The publicly available RICCA Product Specification identifies the lot as SAMPLE. It documents general product specifications but is not a lot-specific certificate for an actual purchased container.
Audit Point: Obtain the certificate associated with the exact received lot when required. Confirm that the certified value and associated uncertainty meet the laboratory's measurement and calibration acceptance requirements.
12. Conductivity Standard Selection and Product Differences
RICCA 2236.02-16 / R2236020-500A: 5 µS/cm sodium chloride conductivity standard at 25°C, 500 mL natural polyethylene bottle.
RICCA 2236.02-32 / R2236020-1A: Same product family and nominal conductivity, supplied in a 1-liter natural polyethylene bottle.
RICCA 2236.03-16 / R2236030-500A: Separately identified 15 µS/cm conductivity standard. Different conductivity concentration for other reference requirements.
RICCA VeriSpec Potassium Chloride Conductivity Standards: A separately branded product family. Verify composition, reference conductivity, uncertainty, and method suitability before substitution.
Selection Principle: Choose conductivity reference standards by the required value, instrument measurement range, certified reference information, applicable measurement uncertainty, and laboratory method requirements.
13. Frequently Asked Technical Questions
What is the conductivity of RICCA R2236020-500A?
Nominal conductivity is 5 µS/cm at 25°C. RICCA's published acceptance range is 4.95-5.05 µS/cm.
Is this standard NIST-traceable?
RICCA's specification documents traceability to NIST SRM 999. Review the lot-specific certificate for the actual received material.
What is its measurement uncertainty?
The published expanded uncertainty is 0.26 µS/cm with k=2. This is distinct from the product's 4.95-5.05 µS/cm acceptance range.
Does 5 µS/cm mean the same as 5 µmho/cm?
Yes. Microsiemens per centimeter and micromhos per centimeter are equivalent units of electrical conductivity.
Can the solution be used for conductivity meter calibration?
It may be used where the instrument and procedure accept a 5 µS/cm reference. Follow instrument manufacturer instructions and approved laboratory requirements.
Why is temperature important?
Conductivity depends on ionic mobility, which changes with temperature. The manufacturer defines the standard's reference value at 25°C.
Why can an opened low-conductivity standard become inaccurate?
Atmospheric carbon dioxide, contaminants, residue from instruments, and repeated handling can affect the ionic composition and measured conductivity.
Is this the same as a total dissolved solids standard?
Conductivity and TDS are related but not identical. Any TDS equivalence depends on solution composition and the calculation method used.
What is the shelf life?
RICCA specifies 12 months for unopened containers. Confirm the actual lot expiration and apply laboratory in-use controls after opening.
How should it be stored?
Recommended storage is 15-30°C. Protect the bottle from freezing, damage, and contamination.
Is the product hazardous for transportation?
The reviewed SDS lists the formulation as not regulated under DOT, IATA, and Canadian TDG transportation requirements.
Is a lot-specific Certificate of Analysis required?
Requirements depend on the applicable laboratory quality system and measurement procedure. Request the actual lot certificate when certified-value documentation is necessary.
Does this standard automatically meet USP <645> requirements?
No. Suitability depends on the current compendial requirements, instrument configuration, measurement procedure, and laboratory qualification process.
Is the product sterile or certified for a specific ISO cleanroom classification?
No product-specific sterile or cleanroom classification is established in the reviewed manufacturer documentation. Controlled-environment use requires appropriate facility assessment.
14. Manufacturer Documentation and References
RICCA 2236.02 Conductivity Standard Product Specification:
View Manufacturer Product Specification (PDF)
RICCA 2236.02 Conductivity Standard Safety Data Sheet:
View Manufacturer Safety Data Sheet (PDF)
SOSCleanroom Product Listing:
RICCA 2236.02-16 Conductivity Standard, 500 mL
Reference Measurement Documents: NIST SRM 999 and the manufacturer-identified test methods SQCP031 and SQCP033. These support the manufacturer's published traceability statement.
Documentation Note: The published RICCA Product Number 2236.02 specification identifies catalog 2236.02-16 and extended part number R2236020-500A. It documents the conductivity acceptance range, expanded uncertainty, reference material, test methods, 500 mL packaging, unopened shelf life, and storage conditions. Confirm the current revisions and obtain actual lot-specific documentation where required.
Why Source RICCA Conductivity Standards Through SOSCleanroom?
- Accurate Reference Selection: Source the specified conductivity value and bottle configuration.
- Measurement Documentation: Assistance locating manufacturer specifications, SDS resources, and lot-specific records.
- Controlled Laboratory Procurement: Purchase conductivity standards alongside other laboratory and controlled-environment products.
- Repeat Purchasing: Maintain consistent manufacturer part number and material identification.
- Technical Selection Support: Obtain sourcing assistance with conductivity reference values, packaging, and related laboratory supplies.
For conductivity standard sourcing and documentation assistance, contact Sales@SOSsupply.com or call 800-443-7101.
The Technical Vault By SOSCleanroom | Information reviewed October 12, 2026
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