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Ricca RV150000-500A Verispec® pH 4.00 Buffer, 500mL Natural Poly Bottle

Ricca RV150000-500A Verispec® pH 4.00 Buffer, 500mL Natural Poly Bottle

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RICCA RV150000-500A VeriSpec® pH 4.00 Buffer, Certified Reference Material, 500 mL

RICCA Chemical Company VeriSpec® pH 4.00 Buffer is a Certified Reference Material (CRM) formulated for precision pH meter calibration, electrode verification, and analytical method validation. Supplied in a 500 mL natural polyethylene bottle, RICCA RV150000-500A provides a colorless, ready-to-use pH reference buffer with a manufacturer-stated specification of pH 4.00 ± 0.01 at 25°C.

This potassium hydrogen phthalate-based buffer is manufactured and tested under RICCA's ISO/IEC 17025 and ISO 17034 accreditation framework. Manufacturer certification documents identify NIST Standard Reference Materials, analytical testing methods, assigned pH values, and expanded measurement uncertainty to support laboratory calibration traceability and controlled quality-assurance programs.

Product Highlight: VeriSpec® pH 4.00 Certified Reference Material with a ±0.01 pH specification at 25°C, documented NIST traceability, ISO/IEC 17025 and ISO 17034 accredited production and testing, and a 24-month unopened shelf life. Supplied as one (1) 500 mL natural polyethylene bottle.

Specifications:
  • Manufacturer: RICCA Chemical Company
  • Product Line: VeriSpec®
  • Product: pH 4.00 Buffer Certified Reference Material
  • Manufacturer Product Number: RV150000
  • Manufacturer Part Number: RV150000-500A
  • Classification: Certified Reference Material (CRM)
  • Nominal pH: 4.00 at 25°C
  • Manufacturer pH Specification: 4.00 ± 0.01 at 25°C
  • Example Lot Expanded Uncertainty: 0.025 pH unit (k=2; lot 16042088)
  • NIST Reference Materials: SRM 185i, 186-I-g, and 186-II-g
  • Manufacturer Test Methods: SQCP027 and SQCP033
  • Accreditation: ISO/IEC 17025 and ISO 17034
  • Buffer System: Potassium hydrogen phthalate
  • Physical Form: Liquid
  • Appearance: Colorless
  • Package Size: 500 mL
  • Container: Natural polyethylene bottle
  • Purchase Quantity: One (1) 500 mL bottle
  • Unopened Shelf Life: 24 months
  • Recommended Storage: 15-30°C (59-86°F)
  • Recommended Use: pH meter calibration and analytical method validation
  • GHS Classification: Not classified as hazardous in the referenced manufacturer SDS
  • DOT/IATA Transportation: Not regulated in the referenced manufacturer SDS

Certification Note: The manufacturer-stated pH specification and reported expanded measurement uncertainty are different quantities. Review the certificate for the actual supplied lot to determine its assigned pH, uncertainty, traceability, and expiration information.

Where VeriSpec® pH 4.00 Buffer Fits in Laboratory Calibration

Accurate pH measurement depends on properly calibrated electrodes, reliable reference solutions, temperature control, and contamination-free analytical procedures.

The RICCA VeriSpec® pH 4.00 buffer provides a certified acidic calibration point for laboratory pH meters and other compatible electrochemical measurement systems.

Unlike ordinary general-purpose laboratory buffers, a Certified Reference Material includes documented property values, measurement uncertainty, and metrological traceability to support controlled calibration and laboratory quality programs.

Typical laboratory fit: Precision pH meter calibration, electrode verification, analytical method validation, multipoint calibration, quality-control testing, and laboratories requiring documented reference-material traceability.

About RICCA VeriSpec® pH Buffers:

pH buffers are reference solutions used to establish and verify the performance of pH measurement systems. Accurate pH readings depend on properly calibrated electrodes, suitable reference solutions, temperature control, and contamination-free measurement procedures.

RICCA VeriSpec® pH buffers are designated Certified Reference Materials and are supported by documentation identifying the assigned property value, associated measurement uncertainty, and metrological traceability.

The RV150000 formulation uses potassium hydrogen phthalate as its principal buffer component and is supplied as a colorless aqueous solution. It is distinct from RICCA's separately identified red color-coded pH 4.00 buffer product family.

About the Manufacturer:

RICCA Chemical Company manufactures laboratory reagents, analytical buffer solutions, and certified reference materials. Its VeriSpec® products support documented calibration programs through specified testing methods, certified values, measurement uncertainty reporting, and NIST-traceable measurement procedures.

RICCA VeriSpec® pH 4.00 Buffer Features:
  • Certified Reference Material (CRM) for pH measurement applications
  • pH 4.00 ± 0.01 specification at 25°C
  • Potassium hydrogen phthalate-based buffer formulation
  • Colorless aqueous liquid
  • Certified pH value supported by manufacturer testing
  • NIST traceability using SRM 185i, 186-I-g, and 186-II-g
  • ISO/IEC 17025 and ISO 17034 accredited manufacturing and testing
  • Manufacturer-defined temperature-dependent pH reference values
  • Ready-to-use 500 mL natural polyethylene bottle
  • 24-month unopened shelf life
  • Recommended storage at 15-30°C
  • Manufacturer Certificate of Analysis and Safety Data Sheet documentation
RICCA VeriSpec® pH 4.00 Buffer Benefits:
  • Certified reference value: Provides a documented pH reference for qualified instrument calibration and verification.
  • Metrological traceability: Manufacturer certification identifies NIST reference materials supporting the measurement chain.
  • Accredited production: ISO/IEC 17025 and ISO 17034 accreditation supports reference material production and analytical quality controls.
  • Measurement uncertainty reporting: Lot documentation provides information needed to assess the reference within an applicable calibration uncertainty budget.
  • Ready-to-use convenience: Eliminates routine preparation of a potassium hydrogen phthalate reference buffer.
  • Reliable product identification: The RV150000-500A part number supports controlled purchasing and calibration-standard inventory management.
  • Practical packaging: The 500 mL bottle supports laboratory dispensing and documented calibration procedures.
Common Applications:
  • pH meter calibration using certified reference buffers
  • Verification of pH electrode performance
  • Multipoint pH calibration programs
  • Analytical method validation and laboratory quality assurance
  • Pharmaceutical and biotechnology laboratory pH measurement
  • Environmental and industrial laboratory testing
  • Quality-system programs requiring documented calibration traceability

Application Note: Verify the instrument manufacturer's calibration requirements and select suitable additional buffer values for multipoint calibration. The pH 4.00 CRM is not a substitute for an entire calibration set when other reference points are required.

Best-Practice Use:
  • Verify the reference: Confirm part number RV150000-500A, the applicable lot certificate, and expiration date.
  • Mix before use: Invert the bottle thoroughly as instructed by RICCA.
  • Use separate portions: Rinse electrodes with one portion of buffer and use a second fresh portion for calibration.
  • Do not dilute: Use the CRM at its supplied concentration.
  • Prevent contamination: Never return dispensed buffer to the stock bottle.
  • Control temperature: Use 25°C for the manufacturer's certified pH value or follow the approved procedure for other temperatures.
  • Close after dispensing: Minimize exposure to atmospheric contamination and acid or base fumes.
  • Store correctly: Maintain 15-30°C and protect from freezing and physical damage.
  • Maintain calibration records: Document the lot, certified value, uncertainty, temperature, and instrument results as required.
Selection Notes:

Colorless vs. Color-Coded pH 4.00 Buffer: RV150000-500A is the colorless VeriSpec® formulation. Do not confuse it with the separately identified red pH 4.00 reference buffer.

pH Specification vs. Measurement Uncertainty: The ±0.01 pH specification at 25°C is distinct from the expanded uncertainty reported in the lot certificate. Both matter when qualifying the material.

Certified Value vs. Temperature Table: RICCA certifies pH at 25°C. Its pH values at other temperatures are calculated reference values rather than individually measured certified values for each lot.

CRM vs. General Laboratory Buffer: Certified Reference Materials include documented property values, measurement uncertainty, and traceability. Select a CRM when those attributes are required by the calibration procedure or laboratory quality system.

Manufacturer Documentation:

RICCA RV150000 Certificate of Analysis - Example Lot 16042088: View Manufacturer CoA (PDF)

RICCA RV150000 Safety Data Sheet: View Manufacturer SDS (PDF)

Documentation Note: The example CoA belongs to manufacturing lot 16042088 and documents its assigned value of pH 3.999 at 25°C with expanded uncertainty 0.025 pH unit. These results must not be attributed to another supplied lot.

Technical Vault: Review the SOSCleanroom Technical Vault for detailed discussion of phthalate-buffer chemistry, certified pH measurement, NIST traceability, ISO accreditation, temperature effects, measurement uncertainty, electrode calibration, reference material handling, and laboratory qualification.

Why Buy From SOSCleanroom?

SOSCleanroom supports certified reference material sourcing, pH measurement supplies, and manufacturer documentation requests for laboratory calibration and quality-control programs.

Questions? Email Sales@SOSsupply.com or call 800-443-7101.

Product information reviewed: October 13, 2026

© 2026 Specialty Optical Systems, Inc. (dba SOSCleanroom). All rights reserved.

 

The Technical Vault By SOSCleanroom
Certified pH Reference Material Potassium Hydrogen Phthalate ISO/IEC 17025 & ISO 17034 NIST Traceability Measurement Uncertainty
RICCA VeriSpec® RV150000-500A: Certified pH 4.00 Buffer Chemistry, NIST Traceability, Measurement Uncertainty & Calibration Guide

RICCA Chemical Company VeriSpec® RV150000-500A is a colorless pH 4.00 Certified Reference Material (CRM) formulated for pH meter calibration and analytical method validation. It is supplied as one 500 mL natural polyethylene bottle and is supported by manufacturer certification documentation identifying assigned pH values, associated uncertainty, and NIST traceability.

The manufacturer's nominal specification is pH 4.00 ± 0.01 at 25°C. The RICCA certificate for example manufacturing lot 16042088 reports an assigned pH of 3.999 at 25°C and an expanded measurement uncertainty of 0.025 pH unit (k=2). These figures represent distinct metrological characteristics and must be interpreted correctly when qualifying the buffer for an analytical procedure.

Technical Takeaway: VeriSpec® RV150000 is a potassium hydrogen phthalate-based Certified Reference Material. Its principal value is documented pH certification supported by reference-material traceability, accredited testing, and controlled production. Accurate calibration requires the correct lot-assigned value, temperature control, fresh buffer portions, and contamination prevention.

1. Understanding pH Measurement and Reference Buffers

pH is a logarithmic measure related to hydrogen-ion activity in an aqueous solution. pH measurement is widely used in analytical chemistry, pharmaceutical testing, biotechnology, water quality, manufacturing, and laboratory process control.

Electrochemical pH meters evaluate electrode potential and convert it to a pH indication through calibration and instrument-specific calculations. Electrode condition, reference junction performance, temperature, and calibration buffers can affect the accuracy of the displayed reading.

Certified pH reference buffers provide a documented measurement reference used to establish or verify instrument response. A pH 4.00 buffer is commonly used as an acidic calibration point within multipoint calibration procedures.

Measurement Principle: A certified buffer supports accurate pH measurement, but it does not independently guarantee a calibrated instrument. Instrument performance, calibration design, electrode condition, and measurement technique remain critical.

2. Verified Product Specifications
  • Manufacturer: RICCA Chemical Company
  • Product Line: VeriSpec®
  • Product Name: Buffer, Certified Reference Material, pH 4.00
  • Manufacturer Product Number: RV150000
  • Manufacturer Part Number: RV150000-500A
  • Reference Material Classification: Certified Reference Material (CRM)
  • Nominal pH: 4.00
  • Manufacturer pH Specification: 4.00 ± 0.01 at 25°C
  • Certified Reference Temperature: 25°C
  • Example Certified Value: pH 3.999 at 25°C (lot 16042088)
  • Example Lot Expanded Uncertainty: 0.025 pH unit
  • Coverage Factor: k=2
  • Manufacturer Test Methods: SQCP027 and SQCP033
  • NIST Reference Materials: SRM 185i, 186-I-g, and 186-II-g
  • Testing Accreditation: ISO/IEC 17025
  • Reference Material Producer Accreditation: ISO 17034
  • Buffer Chemistry: Potassium hydrogen phthalate
  • Appearance: Colorless liquid
  • SDS-Reported Relative Density: 1.01
  • Water Solubility: Miscible
  • Bottle Material: Natural polyethylene
  • Package Volume: 500 mL
  • Purchase Quantity: One (1) bottle
  • Unopened Shelf Life: 24 months
  • Recommended Storage: 15-30°C (59-86°F)
  • Recommended Use: Laboratory calibration and method validation
  • GHS Classification: Not classified as hazardous
  • DOT/IATA Transportation: Not regulated

Lot-Specific Qualification: The published lot 16042088 data demonstrates the manufacturer's certification format. A different manufacturing lot may have a different assigned pH and certificate. Use the certificate corresponding to the actual material received.

3. Chemical Composition and Phthalate Buffer Chemistry

The RICCA RV150000 Safety Data Sheet identifies the following aqueous mixture components:

  • Water: CAS 7732-18-5; 98.95% by weight
  • Potassium Hydrogen Phthalate: CAS 877-24-7; 1.02% by weight
  • Proprietary Preservative: Less than 0.1% by weight

Potassium hydrogen phthalate is also known as potassium acid phthalate or KHP. It provides the principal buffering component of the RV150000 formulation. The phthalate acid-base system supports controlled pH conditions near the manufacturer's specified reference value.

The manufacturer identifies the water used in the buffer as ACS/ASTM/USP/EP grade in its certificate documentation. The finished solution is a formulated aqueous reference material rather than a pure chemical substance.

The preservative is identified as proprietary in the SDS. Its exact chemical identity is not disclosed in the reviewed documentation and should not be inferred from other RICCA products.

Composition Control: The manufacturer SDS identifies mixture components for safety and technical information. It does not authorize laboratories to reproduce the certified reference material by simply mixing those components. Certification depends on manufacturing, characterization, homogeneity, and traceability controls.

4. Certified Reference Material Status and ISO Accreditation

A Certified Reference Material is supported by documentation establishing specified property values, measurement uncertainty, and metrological traceability. These characteristics help laboratories establish a defensible reference for calibration or method evaluation.

RICCA identifies VeriSpec® RV150000 as manufactured and tested under ISO/IEC 17025 and ISO 17034 accreditation.

  • ISO/IEC 17025: Competence requirements for testing and calibration laboratories.
  • ISO 17034: Competence requirements for reference material producers.
  • ANAB Testing Accreditation: Certificate L2387, as identified in example lot 16042088.
  • ANAB Reference Material Producer Accreditation: Certificate AR-3140, as identified in example lot 16042088.
  • Independent Confirmation: RICCA reports verification of the assigned pH by a second qualified chemist.
  • Homogeneity: Manufacturer-controlled mixing procedures support uniformity of the material.
  • Production Records: Batch records document preparation and testing history.

The example certificate also refers to ISO 33401 for reference material certificate content and accompanying documentation.

Accreditation Note: The certificates above are identified on a specific example CoA. Confirm applicable manufacturer accreditation and the lot certificate when those details are required for current procurement or audit records.

5. Certified pH, Specification and Measurement Uncertainty

RICCA specifies pH 4.00 ± 0.01 at 25°C for RV150000. The example Certificate of Analysis for lot 16042088 lists an assigned value of pH 3.999 at 25°C.

The same certificate reports an expanded measurement uncertainty of 0.025 pH unit, calculated with coverage factor k=2. RICCA describes this as corresponding to approximately 95% coverage under a normal-distribution model.

  • Nominal pH: 4.00 at 25°C
  • Manufacturer Product Specification: ±0.01 pH at 25°C
  • Example Lot: 16042088
  • Example Lot Assigned pH: 3.999
  • Example Lot Expanded Uncertainty: 0.025 pH unit
  • Coverage Factor: k=2
  • Reference Temperature: 25°C
  • Test Methods: SQCP027 and SQCP033

Critical Metrology Distinction: The ±0.01 pH product specification describes the manufacturer's stated reference-value requirement, while the reported expanded uncertainty characterizes uncertainty associated with the certified measurement. The two figures must not be presented as interchangeable quantities.

Laboratories selecting a buffer for a precision measurement process should evaluate the certificate's actual assigned value, expanded uncertainty, calibration procedure, and applicable decision rules.

Accuracy Qualification: The CRM's certified reference information does not establish the total uncertainty of the laboratory pH measurement. Instrument calibration, electrode performance, temperature, and sample-related effects must also be considered.

6. NIST Traceability and Reference Measurement Methods

RICCA's RV150000 certification documents identify National Institute of Standards and Technology Standard Reference Materials 185i, 186-I-g, and 186-II-g.

The manufacturer describes an unbroken chain of comparisons connecting the certified reference material with the applicable NIST standards. This metrological traceability supports documented pH measurement and calibration programs.

The example certificate also identifies the manufacturer's pH test methods SQCP027 and SQCP033, calibrated laboratory equipment, and an uncertainty evaluation based on the Guide to the Expression of Uncertainty in Measurement (GUM).

  • Confirm the actual lot-assigned pH value.
  • Review the manufacturer's stated measurement uncertainty.
  • Verify the listed NIST SRM references.
  • Check the certified reference temperature.
  • Confirm that the uncertainty is suitable for the intended calibration.
  • Maintain the certificate with laboratory calibration records.

Traceability Principle: NIST traceability refers to a documented measurement chain. It does not mean that NIST individually tested or certified each commercial RICCA bottle.

7. Temperature Effects and the pH Reference Table

Buffer pH may change with temperature because acid-base equilibrium constants and the behavior of the measurement system depend on temperature.

RICCA certifies the RV150000 pH value at 25°C only. The manufacturer provides additional calculated pH reference values at other temperatures.

The manufacturer certificate lists the following nominal temperature-dependent values:

Temperature Reference pH
0°C4.00
5°C4.00
10°C4.00
15°C4.00
20°C4.00
25°C4.00
30°C4.01
35°C4.02
40°C4.03
45°C4.04
50°C4.06

RICCA states that these non-25°C values are calculated rather than measured individually for each lot. The certificate describes them as accurate to ±0.05 pH unit at their respective temperatures.

Automatic temperature compensation on a pH meter does not eliminate the need to use the correct reference-buffer value or follow the instrument's approved calibration procedure.

Temperature-Control Requirement: Use the certified lot-assigned pH at 25°C when the certified condition is required. For measurements at other temperatures, follow the manufacturer's temperature table and applicable instrument and laboratory procedures.

8. Correct pH Meter Calibration Procedure

The following practical sequence incorporates reference material handling instructions identified by RICCA. The instrument manufacturer's calibration procedure and laboratory's approved SOP govern the actual calibration process.

  1. Verify the reference material: Confirm RV150000-500A, lot identification, expiration date, and certificate.
  2. Check the assigned pH: Review the actual lot-certified value and reference temperature.
  3. Mix the buffer: Thoroughly invert the bottle before use.
  4. Inspect the electrode: Verify suitability, physical condition, and maintenance status.
  5. Prepare a rinse portion: Dispense a small amount of fresh buffer for electrode rinsing.
  6. Prepare a calibration portion: Dispense a separate fresh portion for the pH measurement.
  7. Control temperature: Use the reference temperature and measurement conditions required by the procedure.
  8. Calibrate the instrument: Follow the manufacturer's instructions for calibration point selection, stabilization, and acceptance.
  9. Evaluate performance: Review displayed pH, electrode slope, offset, and other applicable criteria.
  10. Document results: Record instrument identification, reference material lot, assigned value, temperature, and calibration outcome.
  11. Discard used portions: Do not return any used or dispensed buffer to the original bottle.
  12. Close the original container: Protect the remaining CRM from environmental contamination.

Calibration Note: A single pH 4.00 point is not automatically adequate for every measurement range or method. Use the number and selection of calibration buffers required by the instrument and laboratory procedure.

9. Contamination Control and Bottle-Opening Uncertainty

Reference material integrity can be affected by evaporation, contamination, repeated exposure to laboratory air, and contact with improperly cleaned equipment.

RICCA instructs users to dispense only enough buffer for immediate use, avoid dilution, and never return used material to the bottle. The stock container should remain tightly closed and be protected from acid or base fumes.

An additional statement appears on the manufacturer's example CoA: Each time the bottle is opened, the uncertainty of the certified value increases by 0.0021 pH unit.

This manufacturer statement highlights why repeated opening and exposure should be controlled. Laboratories should use the current applicable certificate and approved measurement uncertainty procedure to interpret this increase.

  • Protect the stock bottle: Avoid inserting contaminated equipment into the reference material.
  • Use fresh portions: Separate electrode rinsing and calibration solutions.
  • Prevent evaporation: Avoid unnecessarily prolonged opening.
  • Control environmental exposure: Keep away from acid, base, and other contaminating fumes.
  • Track usage when required: Document opening events according to the laboratory quality system.
  • Discard used material: Do not reuse contaminated calibration portions.
  • Maintain cap integrity: Close the original container promptly after dispensing.

Reference Material Integrity: The original certified value is supported by the manufacturer's characterization and handling conditions. Careless dispensing or repeated contamination may compromise the suitability of the buffer for precision calibration.

10. Storage, Shelf Life and Stability

RICCA specifies a recommended storage temperature of 15-30°C (59-86°F) and a 24-month unopened shelf life for RV150000-500A.

The manufacturer's Safety Data Sheet directs users to protect the solution from freezing and physical damage. The CRM certificate additionally recommends keeping the container tightly closed and away from acid or base fumes.

  • Recommended Temperature: 15-30°C
  • Original Container: Natural polyethylene bottle
  • Closure: Keep tightly closed when not dispensing
  • Freezing: Protect from freezing
  • Physical Damage: Prevent bottle damage or leakage
  • Environmental Exposure: Avoid acid or base fumes
  • Chemical Compatibility: Follow the SDS, which identifies nitric acid as incompatible
  • Expiration: Use the date assigned to the actual manufacturing lot
  • After Opening: Follow manufacturer handling instructions and laboratory in-use controls

The example certificate for lot 16042088 lists a manufacture date of April 30, 2026, and expiration in April 2028. These dates apply to that particular lot and do not establish the expiration date of every bottle sold.

Shelf-Life Limitation: The 24-month shelf life applies to unopened containers. It should not be interpreted as a universal 24-month in-use period after opening, particularly where measurement uncertainty and contamination controls are critical.

11. Safety and Transportation Classification

RICCA's RV150000 Safety Data Sheet identifies the reference buffer as not classified as hazardous under GHS according to the referenced criteria.

  • GHS Classification: Not classified as hazardous
  • GHS Signal Word: None required
  • GHS Hazard Pictograms: None required
  • DOT Ground Transportation: Not regulated
  • IATA Air Transportation: Not regulated
  • Canadian TDG Transportation: Not regulated
  • Eye Protection: Safety glasses or goggles
  • Hand Protection: Chemical-resistant gloves
  • Ventilation: Normal room ventilation identified as adequate
  • Flammability: SDS identifies the solution as non-flammable
  • Possible Contact Effects: Slight skin or eye irritation

Although the product does not meet the SDS criteria for GHS hazard classification, standard laboratory chemical hygiene and appropriate handling procedures remain necessary.

Safety Notice: Consult the current RICCA Safety Data Sheet for first aid, safe handling, spill response, chemical incompatibility, and disposal requirements. The reviewed U.S. SDS revision is dated May 4, 2026.

12. Laboratory Quality Documentation and Audit Readiness

Certified reference materials are commonly used within controlled calibration and laboratory quality-management systems. The certification and identification records should support traceability of the material actually used.

  • Lot-Specific Certificate of Analysis: Documents the actual assigned pH, uncertainty, and traceability information.
  • Manufacturer Part Number: Identifies the exact 500 mL reference material configuration.
  • Accreditation Information: Supports assessment of the manufacturer's reference material production and testing framework.
  • NIST Traceability: Identifies relevant SRMs and measurement chain.
  • Reference Temperature: Establishes the conditions under which the assigned value is certified.
  • Expiration Date: Identifies the manufacturer-assigned use limitation for the received lot.
  • Safety Data Sheet: Provides product composition, hazard, and handling information.
  • Instrument Records: Connects the certified buffer to individual calibration or verification events.
  • Measurement Uncertainty: Supports suitability assessment for the laboratory's measurement process.
  • In-Use Control: Supports appropriate handling and documentation of bottle-opening events.

Unlike a generic sample specification, RICCA's publicly available certificate for lot 16042088 contains an actual assigned value, manufacturing date, expiration information, and reported measurement uncertainty for that specific manufacturing lot.

Audit Point: The existence of a genuine public lot certificate does not establish that the customer received that lot. Always match the certificate's lot number against the physical container before relying on its assigned value or expiration date.

13. VeriSpec® pH Buffer Selection and Product Differences

RICCA RV150000-500A: Colorless VeriSpec® pH 4.00 Certified Reference Material, 500 mL natural polyethylene bottle. Manufacturer specification of pH 4.00 ± 0.01 at 25°C.

RICCA RV150000-1A: The 1-liter natural polyethylene configuration of the same RV150000 CRM product family.

RICCA Red pH 4.00 Buffer: A separately identified color-coded reference buffer product family. Confirm the exact manufacturer part number and certificate before selecting it as an alternative.

RICCA RV155000-500A: VeriSpec® pH 7.00 certified reference buffer in a 500 mL natural polyethylene bottle, intended for calibration procedures requiring a neutral reference point.

RICCA RV160000-500A: VeriSpec® pH 10.00 certified reference buffer in a 500 mL natural polyethylene bottle, intended for calibration procedures requiring an alkaline reference point.

General pH Buffer vs. CRM: Products may have similar nominal pH values while differing in reference-material certification, reported uncertainty, traceability, formulation, and documentation.

Selection Principle: Choose calibration buffers according to the required pH, sample measurement range, calibration-point selection, certification, uncertainty, instrument requirements, and laboratory quality procedures.

14. Frequently Asked Technical Questions

What is the certified pH of RICCA RV150000-500A?

The nominal manufacturer specification is pH 4.00 ± 0.01 at 25°C. The exact assigned value depends on the manufacturing lot.

Is this a Certified Reference Material?

Yes. RICCA identifies VeriSpec® RV150000 as a CRM manufactured and tested under ISO/IEC 17025 and ISO 17034 accreditation.

Is the buffer NIST-traceable?

RICCA's certification identifies traceability to NIST SRM 185i, 186-I-g, and 186-II-g.

What is the actual pH for example lot 16042088?

The manufacturer reported pH 3.999 at 25°C. That result belongs to lot 16042088 and must not be assigned to another lot.

What measurement uncertainty applies?

The example certificate reports an expanded uncertainty of 0.025 pH unit with coverage factor k=2. Review the certificate for the actual received lot.

Why is the expanded uncertainty different from the ±0.01 pH specification?

The product specification and expanded uncertainty describe different metrological quantities. They must be considered separately when evaluating the reference material's suitability.

Is RV150000 color-coded red?

No. RV150000 is documented as a colorless liquid. RICCA also offers separately identified red color-coded pH 4.00 buffers.

What chemical provides the buffer system?

Potassium hydrogen phthalate, CAS 877-24-7, is the principal buffering component.

Is a preservative present?

The RICCA SDS identifies a proprietary preservative at less than 0.1% by weight. Its exact chemical identity is not provided in the reviewed SDS.

At what temperature is the pH certified?

RICCA certifies the assigned pH at 25°C. Values published for other temperatures are calculated rather than individually measured and certified for each lot.

Should the bottle be mixed before use?

Yes. RICCA instructs users to mix thoroughly by inversion before each use.

Can the CRM be diluted?

No. The manufacturer instructs users not to dilute the reference buffer.

Can dispensed buffer be returned to the bottle?

No. Returning used buffer may contaminate the stock reference material and compromise its suitability for calibration.

Does opening the bottle affect the stated uncertainty?

RICCA's example certificate states that the certified-value uncertainty increases by 0.0021 pH unit for each opening. Follow the applicable manufacturer certificate and laboratory uncertainty-control procedure.

What is the unopened shelf life?

RICCA specifies 24 months. The actual expiration date must be verified for the specific received lot.

How should the buffer be stored?

Recommended storage is 15-30°C. Keep tightly closed, protect from freezing and physical damage, and avoid acid or base fumes.

Is the solution hazardous for transportation?

The reviewed SDS identifies the material as not regulated under DOT, IATA, and Canadian TDG dangerous-goods transportation requirements.

Does the publicly available CoA certify every bottle sold?

No. The publicly available certificate documents a specific lot. A laboratory must verify the certificate corresponding to the material actually received.

Is the product sterile or ISO cleanroom-classified?

No product-specific sterility or ISO cleanroom compatibility certification is established by the reviewed manufacturer documents. Facility qualification is necessary where controlled-environment requirements apply.

15. Manufacturer Documentation and Technical References

RICCA VeriSpec® RV150000 Certificate of Analysis - Lot 16042088:

View Manufacturer Lot-Specific CoA (PDF)

RICCA VeriSpec® RV150000 Safety Data Sheet:

View Manufacturer SDS (PDF)

RICCA RV150000 Regulatory Compliance Summary:

View Regulatory Compliance Summary (PDF)

SOSCleanroom Product Listing:

RICCA RV150000-500A VeriSpec® pH 4.00 Buffer, 500 mL

Metrology References: ISO/IEC 17025, ISO 17034, ISO 33401, NIST SRM 185i, NIST SRM 186-I-g, NIST SRM 186-II-g, and manufacturer methods SQCP027 and SQCP033, as identified in RICCA certification documentation.

Documentation Note: Example lot 16042088 was manufactured April 30, 2026, and carries an April 2028 expiration. Its CoA reports an assigned pH of 3.999 at 25°C and expanded uncertainty of 0.025 pH unit. These are genuine manufacturer lot-specific records but do not establish the lot identity or certified values of future SOSCleanroom shipments.

Why Source RICCA VeriSpec® Reference Materials Through SOSCleanroom?
  • Accurate Product Identification: Source the correct VeriSpec® reference material using its full manufacturer part number.
  • Calibration Material Selection: Choose appropriate pH values and bottle configurations for laboratory instrumentation.
  • Manufacturer Documentation: Obtain assistance locating certificates, Safety Data Sheets, and product information.
  • Controlled Procurement: Maintain consistent approved reference materials for repeat calibration work.
  • Laboratory Quality Support: Source certified reference buffers alongside laboratory reagents and other controlled-environment supplies.
  • Technical Selection Assistance: Distinguish colorless, color-coded, certified, and general-purpose buffer products.

For certified pH reference material sourcing and manufacturer documentation assistance, contact Sales@SOSsupply.com or call 800-443-7101.

The Technical Vault By SOSCleanroom
Information reviewed October 13, 2026
© 2026 Specialty Optical Systems, Inc. (dba SOSCleanroom). All rights reserved.