Binzhenghong PTFE Calibration Weight Set (20 g) with PTFE Tweezers and Glass Storage Tube

Overview

The Binzhenghong PTFE Calibration Weight Set (20 g) is engineered specifically for high-integrity mass calibration and verification procedures in pharmaceutical quality control laboratories operating under pharmacopoeial compliance frameworks—including USP <41>, EP 2.1.1, and ChP General Chapter 0631. Unlike conventional stainless-steel or brass weights, this set utilizes solid, homogenous polytetrafluoroethylene (PTFE) as the primary mass standard material—selected for its exceptional chemical inertness, low surface energy, and negligible hygroscopicity. The 20 g weight conforms to a nominal diameter of 22 mm and is manufactured to a maximum permissible error of ±0.1 g, aligning with OIML R111 guidance for non-metallic weights used in Class F2-equivalent applications where environmental corrosion resistance and contamination avoidance are critical. Its design eliminates electrostatic adhesion, metal ion leaching, and surface adsorption—key failure modes observed when metallic weights contact aggressive solvents, lyophilized APIs, or highly purified excipients during balance performance qualification (PQ) and routine calibration.

Key Features

• Solid, machined PTFE construction—no fillers, laminates, or coatings—to ensure long-term density stability and thermal expansion consistency (CTE ≈ 1.1 × 10⁻⁴ K⁻¹)
• Dimensionally optimized cylindrical geometry (Ø22 mm × H18 mm) for stable placement on analytical and micro-balance pans without tipping or rolling
• Surface finish Ra ≤ 0.4 µm—minimizing particulate shedding and facilitating ISO 14644-1 Class 5 cleanroom-compatible cleaning protocols
• Accompanied by PTFE-handled tweezers (non-magnetic, non-shedding tip geometry) to eliminate direct skin contact and prevent fingerprint-induced mass drift
• Supplied in a sealed borosilicate glass tube with PTFE-lined cap—providing inert, humidity-controlled storage compliant with GLP documentation requirements
• Traceable as a working standard: each unit carries a unique alphanumeric identifier laser-engraved on the base for audit-ready instrument history tracking

Sample Compatibility & Compliance

This PTFE weight set is validated for use across regulated environments requiring adherence to ICH Q7, FDA 21 CFR Part 211, and EU GMP Annex 15. It meets the material suitability criteria defined in USP <1058> Analytical Instrument Qualification for “reference standards used in balance verification,” particularly where metallic interference must be excluded—e.g., in weighing highly reactive intermediates (e.g., sodium hydride), moisture-sensitive compounds (e.g., anhydrous theophylline), or cytotoxic APIs. The PTFE composition ensures full compatibility with aggressive cleaning agents (e.g., 30% HNO₃, piranha solution, acetone/water mixtures) without dimensional change or mass loss. While not certified to OIML R111 Class E2 or F1, its ±0.1 g tolerance satisfies internal calibration intervals for balances with readability ≥0.1 mg per USP <41> acceptance criteria.

Software & Data Management

As a passive physical standard, the weight set does not interface with software. However, its traceability supports digital calibration workflows: the engraved ID enables direct linkage to electronic lab notebook (ELN) entries or LIMS records documenting balance verification events. When used within a validated calibration management system (e.g., MET/TEAM, LabWare LIMS), the weight’s certification history—including initial verification date, re-verification schedule (recommended annually), and environmental exposure log—can be maintained with full 21 CFR Part 11-compliant audit trails. Documentation includes a manufacturer’s Certificate of Conformance (CoC) listing raw material lot number, machining batch ID, and dimensional inspection report.

Applications

• Periodic performance verification of analytical balances (0.1 mg–1 mg readability) in QC labs conducting assay, content uniformity, and dissolution testing
• Installation qualification (IQ) and operational qualification (OQ) of automated dispensing systems handling potent compounds
• Calibration of microbalances used in residual solvent analysis (GC headspace) sample preparation
• Weighing reference standards for HPLC method validation where metallic contamination would compromise column lifetime or detector response
• Inert weighing support during sterile filtration validation studies involving aggressive sterilants (e.g., vaporized hydrogen peroxide)

FAQ

Is this weight suitable for ISO/IEC 17025 accredited calibration labs?
Yes—provided it is used as a secondary working standard within a documented uncertainty budget and supported by periodic inter-laboratory comparison or verification against a higher-tier certified reference material.
Can the PTFE weight be autoclaved?
No. PTFE softens above 260 °C; steam autoclaving (121 °C, 15 psi) is permissible only if cycle duration is strictly limited to ≤15 minutes and cooling occurs in inert atmosphere to avoid thermal stress cracking.
Does the glass storage tube meet USP <660> requirements for pharmaceutical packaging?
The borosilicate glass tube complies with USP <660> Type I classification for hydrolytic resistance and extractables profile, though final packaging qualification remains the responsibility of the end-user’s packaging validation protocol.
How often should re-verification be performed?
Annual verification is recommended under typical lab conditions; more frequent checks (e.g., quarterly) are advised in high-humidity environments (>60% RH) or where the weight undergoes >10 daily handling cycles.
Is a formal calibration certificate included?
A Certificate of Conformance (CoC) is supplied. A UKAS or ILAC-MRA accredited calibration certificate requires third-party metrology lab engagement and is available upon separate request.