Novasina LabTouch-aw Desktop Temperature-Controlled Water Activity Analyzer

Overview

The Novasina LabTouch-aw is a precision desktop water activity (a_w) analyzer engineered for laboratories requiring traceable, thermodynamically grounded measurements of equilibrium relative humidity (ERH) in solid and semi-solid matrices. It operates on the principle of resistive electrolytic hygrometry — a method patented and refined by Novasina over four decades — wherein a proprietary electrolyte-based sensor detects the partial vapor pressure of water above a sample at thermodynamic equilibrium. This direct measurement eliminates reliance on empirical correlations or calibration curves, delivering a_w values traceable to NIST-certified saturated salt standards. Unlike gravimetric or dew-point methods, the LabTouch-aw achieves full equilibrium detection within minutes for most food, pharmaceutical, and chemical samples, while maintaining ISO/IEC 17025-compliant uncertainty budgets. Its integrated Peltier-based temperature control (15–30 °C) ensures measurement repeatability under standardized thermal conditions, critical for method validation per FDA Guidance for Industry (2022), USP , and ISO 21807:2022.

Key Features

• Integrated thermoelectric (Peltier) temperature regulation with ±0.15 K stability across 15–30 °C — enabling controlled a_w assessment per ASTM F1980-21 accelerated stability protocols
• Resistive electrolytic sensor (CM-2 type) with >10-year operational lifetime and zero routine maintenance requirements
• High-resolution capacitive touchscreen interface (7-inch LCD) supporting multilingual UI and intuitive method-driven workflows
• Onboard storage for ≥1,000 test records including timestamps, user IDs, method parameters, and environmental metadata
• Modular filtration options (e.g., activated charcoal, hydrophobic PTFE) to suppress interference from volatile organic compounds (VOCs), ethanol, or solvents — essential for confectionery, fermented products, and solvent-based pharmaceutical intermediates
• Compliance-ready architecture: audit trail logging, electronic signature support, and configurable user access levels aligned with FDA 21 CFR Part 11 and EU Annex 11 requirements

Sample Compatibility & Compliance

The LabTouch-aw accommodates heterogeneous samples up to 10 g in standard 35-mm diameter sample cups, including powders (milk protein isolate, starches), pastes (cheese spreads, meat emulsions), gels (hydrocolloid systems), and low-moisture solids (cereals, dried herbs, lyophilized APIs). Its sealed measurement chamber maintains inert atmosphere integrity during equilibration, minimizing oxidation artifacts. All measurements conform to ISO 21807:2022 (Foodstuffs — Determination of water activity), AOAC Official Method 978.18, and USP (Application of Water Activity Determination to Nonsterile Pharmaceutical Products). The instrument’s traceability chain — anchored to NIST-traceable saturated salt reference standards (e.g., LiCl, MgCl₂, NaCl) — satisfies GLP/GMP laboratory accreditation criteria under ISO/IEC 17025:2017 Clause 6.4.2.

Software & Data Management

Data export is supported via SD card (FAT32 formatted), USB mass storage mode, or RS-232 serial interface (ASCII protocol) for integration into LIMS or MES platforms. The native firmware enables creation and recall of up to 20 user-defined test methods, each specifying target temperature, equilibration timeout (1–120 min), auto-zero cycles, and pass/fail thresholds. Audit trails record all operator actions, parameter changes, and calibration events with immutable timestamps. Optional Novasina WinControl software (Windows-based) provides advanced statistical analysis — including Shewhart control charts, trend analysis across batches, and automated report generation compliant with ICH Q5C stability guidelines.

Applications

• Food R&D & QA: Predicting microbial shelf life (e.g., inhibition of Staphylococcus aureus at a_w < 0.86; Clostridium botulinum proteolytic type B at a_w < 0.93), optimizing drying endpoints, validating HACCP critical limits
• Pharmaceutical manufacturing: Monitoring excipient compatibility, assessing moisture-induced degradation kinetics of APIs, qualifying desiccant packaging per ICH Q1A(R2)
• Tobacco processing: Controlling leaf conditioning stability and preventing mold growth during bulk storage
• Chemical & coating industries: Verifying binder hydration states in adhesives, evaluating anti-caking agent efficacy in fertilizers
• Academic research: Studying sorption isotherms (GAB, BET models), glass transition behavior (T_g), and moisture migration in multilayer packaging systems

FAQ

What is the fundamental measurement principle used by the LabTouch-aw?

It employs resistive electrolytic hygrometry — measuring the electrical conductivity change of a thin-film electrolyte exposed to sample headspace vapor at equilibrium.
Does the instrument require daily calibration?

No. It uses factory-calibrated, NIST-traceable saturated salt standards; verification checks are recommended before each analytical session per ISO 21807:2022 Annex B.
Can it measure samples containing ethanol or organic solvents?

Yes — when equipped with optional VOC-resistant filters, which prevent sensor poisoning and cross-sensitivity in alcoholic beverages, tinctures, or solvent-based formulations.
How does temperature control improve measurement reliability?

By stabilizing the sample chamber at a defined setpoint, it eliminates thermal drift effects on vapor pressure, ensuring comparability across labs and compliance with regulatory temperature stipulations (e.g., USP Section 3.2).
Is the LabTouch-aw suitable for GMP-regulated environments?

Yes — its electronic signature capability, configurable user roles, and full audit trail functionality meet FDA 21 CFR Part 11 and EU Annex 11 requirements for computerized system validation.