duoPUR Ultra-High-Purity Acid Purification System by Milestone

Overview

The duoPUR Ultra-High-Purity Acid Purification System by Milestone is an engineered solution for the production of sub-part-per-trillion (sub-ppt) grade mineral acids—primarily hydrochloric (HCl), nitric (HNO₃), and hydrofluoric (HF) acids—required in ultra-trace elemental analysis. It operates on the principle of sub-boiling infrared radiative distillation: a non-contact, surface-selective heating method wherein infrared radiation uniformly heats only the liquid–vapor interface of the acid sample, minimizing thermal decomposition, splashing, and carryover of particulate or volatile impurities. Unlike conventional boiling distillation or reflux-based systems, sub-boiling distillation avoids nucleate boiling and turbulent vapor generation, thereby preserving acid integrity while selectively volatilizing the target acid component. This physical separation mechanism is particularly critical for eliminating metal contaminants (e.g., Al, Fe, Cu, Pb, U) and anionic impurities that originate from reagent-grade acid batches and compromise detection limits in ICP-MS, ICP-OES, and HR-ICP-MS applications.

Key Features

• Non-contact infrared radiative heating: Eliminates direct contact between heating elements and acid, preventing metallic leaching and ensuring consistent thermal profile across the quartz surface.
• Fused quartz distillation chamber: Chemically inert, low-background material with certified trace-metal content (<10 pg/g for key elements), validated per ASTM D5127 and ISO 3696 Grade 1 water purity benchmarks.
• High-efficiency water-cooled condenser: Optimized thermal gradient ensures rapid, complete vapor-to-liquid phase transition with minimal back-diffusion or re-evaporation.
• Automated liquid handling: Integrated peristaltic feed and drain modules enable unattended operation; programmable volume thresholds trigger acid replenishment or waste evacuation.
• Intelligent touchscreen HMI: 7-inch color display with multi-language support, user-defined purification protocols (e.g., single-pass vs. double-pass), real-time temperature logging, and event-driven alarm history.
• Dual thermal safety architecture: Independent overtemperature cutoff and dry-run detection sensors prevent quartz chamber damage and ensure GLP-compliant operational continuity.

Sample Compatibility & Compliance

The duoPUR system is validated for purification of concentrated HCl (37%), HNO₃ (69%), and HF (48%)—all commonly used in microwave-assisted digestion, standard dilution, and calibration stock preparation. It meets the stringent blank requirements defined in EPA Method 200.8 and USP / for elemental impurities. The system’s design supports full auditability under ISO/IEC 17025:2017 and FDA 21 CFR Part 11 when paired with optional electronic signature and data archiving modules. All wetted parts—including condenser tubing, collection vials, and transfer lines—are fabricated from high-purity fused quartz or PFA, eliminating polymer-derived carbon or fluorine contamination.

Software & Data Management

The embedded control firmware records time-stamped parameters—including surface temperature, cooling water inlet/outlet temperatures, distillation duration, and cycle completion status—for each run. Data export is supported via USB and Ethernet (Modbus TCP) to LIMS or ELN platforms. Optional software packages provide automated report generation compliant with GLP documentation standards, including electronic signatures, version-controlled protocol libraries, and immutable audit trails for QA/QC review.

Applications

• Preparation of calibration standards and internal standards for ICP-MS quantification at sub-ng/L levels.
• Blank reduction in environmental water, soil digestates, and biological tissue extracts.
• Supporting reference material certification workflows (e.g., NIST SRM preparation).
• Enabling low-background geochemical analysis (e.g., Lu–Hf, Sm–Nd isotope ratio measurements).
• Facilitating semiconductor-grade etchant formulation where Na, K, and Fe must remain below 0.1 ppt.

FAQ

What acid types are compatible with the duoPUR system?
Hydrochloric acid (37%), nitric acid (69%), and hydrofluoric acid (48%) are fully supported. Other mineral acids (e.g., perchloric, sulfuric) require prior validation due to thermal stability and corrosion considerations.
Does the system meet ISO 17025 traceability requirements?
Yes—the system enables full parameter logging, user authentication, and protocol versioning. When integrated with certified calibration services and external temperature validation, it satisfies clause 6.4.10 (Equipment Records) and 7.7 (Ensuring Validity of Results).
How is cross-contamination prevented between runs?
The fused quartz chamber is inert and non-porous; residual acid is fully evacuated via automated drain sequence, followed by optional nitrogen purge. No rinse solvents are required.
Can the system be integrated into a centralized lab automation network?
Yes—via Modbus TCP or OPC UA interfaces, enabling remote monitoring, scheduling, and alarm forwarding to enterprise SCADA or LabVantage environments.