METTLER TOLEDO pH 4.01 / 7.00 / 9.21 Certified Buffer Solutions Set

Overview

METTLER TOLEDO pH 4.01 / 7.00 / 9.21 Certified Buffer Solutions Set is a rigorously validated, traceable reference standard designed for high-accuracy two- or three-point calibration of laboratory and industrial pH meters, electrodes, and portable pH analyzers. These solutions are formulated in strict accordance with ISO 3696 (Grade 2 water), DIN 19265, and ASTM D1293 requirements for electrochemical reference standards. Each batch undergoes independent metrological validation at METTLER TOLEDO’s certified calibration laboratory in Shanghai, with full traceability to primary NIST SRM 186, SRM 187, and SRM 188 reference materials. The pH values—4.01, 7.00, and 9.21—are selected to span the most critical regions of the pH scale: acidic, neutral, and alkaline domains—enabling comprehensive electrode slope and asymmetry potential assessment. Unlike generic buffer preparations, these solutions incorporate proprietary stabilizing agents that suppress CO₂ absorption (particularly critical for pH 9.21) and minimize temperature-induced drift, ensuring stable readings across ambient lab conditions (15–30 °C).

Key Features

• Certified uncertainty of ±0.02 pH at 25 °C, verified per ISO/IEC 17025-accredited procedures
• Individually labeled bottles with unique batch numbers and expiration dates; each set includes an original Certificate of Analysis (CoA) bearing METTLER TOLEDO’s authorized signature and accreditation seal
• Formulated using ultra-pure reagents and conductivity-controlled deionized water (resistivity ≥15 MΩ·cm) to prevent ionic interference during calibration
• Stabilized pH 9.21 formulation resists carbonate formation for >120 minutes after opening, extending usable window without compromising accuracy
• Compatible with all METTLER TOLEDO pH meters (e.g., SevenCompact™, SevenExcellence™, FE28) as well as third-party instruments meeting IEC 62304 and EN 61326-1 electromagnetic compatibility standards
• No preservatives added; sterile filtration (0.22 µm) ensures microbiological stability over the full 24-month shelf life when stored unopened at 15–25 °C

Sample Compatibility & Compliance

This buffer set is intended exclusively for instrument calibration—not for sample measurement or process control. It meets the minimum specification requirements for GLP and GMP environments under FDA 21 CFR Part 11 when used in conjunction with audit-trail-enabled METTLER TOLEDO titrators or pH platforms. The CoA satisfies ISO/IEC 17025 clause 5.10.2 for reporting measurement uncertainty and supports IQ/OQ/PQ validation protocols in regulated pharmaceutical, biotech, and drinking water laboratories. Each solution complies with EU Directive 2009/48/EC (Toy Safety) and USP “Acid-Base Titrations” for pH standardization in compendial testing.

Software & Data Management

When used with METTLER TOLEDO’s LabX™ software, the buffer lot numbers can be scanned directly into calibration records, automatically populating metadata—including CoA reference, expiry date, and certified pH values—into secure, time-stamped electronic lab notebooks. LabX enforces role-based access control and generates 21 CFR Part 11-compliant audit trails for all calibration events. For standalone use, printed CoAs include QR-coded batch data for real-time verification against METTLER TOLEDO’s global certificate database (accessible via serial number lookup on mettlertoledo.com/certificates).

Applications

• Two-point calibration (pH 4.01 and 7.00) for routine QC testing of aqueous samples in food & beverage, environmental monitoring, and wastewater treatment
• Three-point calibration (pH 4.01, 7.00, 9.21) for validating electrode response linearity and detecting aging-related drift in R&D labs and method development studies
• Verification of pH meter performance prior to USP , EP 2.2.3, or JP 2.03 compliance testing
• Benchmarking of field-deployable sensors in EPA Method 150.1 and APHA Standard Methods 4500-H⁺ B
• Training and proficiency testing in accredited calibration laboratories operating under ISO/IEC 17025 scope

FAQ

Are these buffers certified for ISO/IEC 17025 compliance?

Yes—each batch is issued a manufacturer’s Certificate of Analysis compliant with ISO/IEC 17025:2017 clause 7.7, including expanded uncertainty (k=2), coverage factor, and traceability statement.
Can I use pH 9.21 buffer beyond 2 hours after opening?

For metrologically valid results, METTLER TOLEDO recommends discarding opened pH 9.21 solution after 120 minutes due to atmospheric CO₂ equilibration; pH 4.01 and 7.00 remain stable for up to 4 hours when protected from contamination.
Does the CoA include temperature correction tables?

Yes—the official CoA provides pH values at 10 °C, 15 °C, 20 °C, 25 °C, 30 °C, and 35 °C, calculated per NIST IR 6919 methodology and referenced to the IUPAC-recommended temperature function for phosphate and borate buffers.
Is this product suitable for USP conformance testing?

Yes—these buffers meet the “certified reference standard” requirement defined in USP section 1.2, and are routinely employed in compendial method validation across Tier-1 pharmaceutical contract labs.
What is the shelf life after opening?

Unopened: 24 months from manufacture date. Opened: 6 months if stored at 15–25 °C in original bottle with cap tightly sealed and protected from light and dust—but metrological validity for calibration is limited to 2 hours for pH 9.21 and 4 hours for pH 4.01/7.00.