Moisture control is essential in food, feed and R&D labs. Whether checking raw materials, monitoring product stability, or validating formulations, accurate moisture analysis ensures quality, safety, and regulatory compliance.
The most efficient way to measure moisture accurately is with a moisture analyser. However, to obtain repeatable and trustworthy results, you must consider sample handling, drying protocols, instrument calibration, and the selection of an appropriate method.
What is a Moisture Analyser And How It Works?
A moisture analyser determines the moisture percentage by recording the weight loss as a sample is dried under controlled heating conditions. The principle is based on thermogravimetric analysis (TGA):
Moisture (%) = (Initial Weight – Final Weight) / Initial Weight × 100
Modern instruments feature halogen or IR heating elements for rapid and uniform heat distribution, real-time weight tracking, and programmable methods tailored to sample types.
| Key Features | Value in Laboratory Use |
| Halogen Heating | Faster evaporation, stable temperature control |
| Real-Time Weight Monitoring | Detects endpoint dynamically, avoids over-drying |
| Method Storage | Ensures repeatability across routine batches |
| Temperature Range | Typically 30 -200°C, adjustable in 1 °C increments |
These units are commonly used across QC, R&D, and formulation labs handling active materials, hygroscopic excipients, lyophilised drug products, and analytical standards.
Why Moisture Analysis Matters in Analytical Workflows?
If you’re preparing reference solutions, assay standards, or chromatographic mobile phases, even trace moisture can alter performance.
| Use Case | Moisture Risk |
| Lyophilised APIs | Reduced potency during storage |
| Powder excipients | Poor flow and inconsistent dosing |
| HPLC sample preparation | Solvent dilution inconsistency |
| GC volatile analysis | Interference due to residual water |
For regulated workflows, laboratories often require methods validated to USP/EP/ICH standards, especially when results are part of batch release specifications.
Calibration and Routine Verification
Moisture analysers must be regularly calibrated to avoid drift. Both the balance and heating module require verification.
| Calibration Area | How to Calibrate | Frequency |
| Weighing System | Using E2/F1 class certified weights | Weekly or per SOP |
| Temperature Module | Use a reference thermometer probe on the pan | Monthly or quarterly |
| Method Validation | Run known standards (e.g. Di-sodium tartrate) | Post-maintenance or quarterly |
For labs preparing documentation for audits or COA submissions, it is important to log calibration history. Instruments that allow auto-logging or printouts are useful in maintaining GMP/GLP compliance.
Common Issues
Operators should avoid assuming the analyser will compensate for poor prep. Even minor inconsistencies can cause outliers or failed method verification.
| Issue | Impact | Preventive Action |
| Sample overload | Incomplete drying or heat gradients | Stick to recommended weights (≤5 g) |
| Uneven spreading | Edge drying and centre retention | Use a spatula to flatten |
| Dirty or reused pans | Residual mass error | Use new or thoroughly cleaned pans |
| Incorrect endpoint setting | Over-drying or premature stop | Validate the method across multiple trials |
Drying should be observed during method development. The weight vs time curve should plateau without rehydration or mass fluctuation. Many newer units include visual displays of drying curve trends.
Selecting a Moisture Analyser Based on Laboratory Requirements
Different lab setups demand different capabilities from their moisture analyser. A small QC lab focused on excipient testing does not need the same profile storage or resolution as a formulation lab handling complex, multi-stage drying of biologics.
Below is a comparison matrix to guide technical selection:
| Lab Type | Essential Features | Recommended Range |
| Basic QC (routine excipient testing) | Single-temp drying, manual tare, basic LCD | Entry-level, 0.01% readability |
| Formulation lab | Programmable steps, higher precision balance | 0.001 g readability, halogen heater |
| Analytical prep (HPLC/GC support) | Ramp profiles, custom ID tagging, and real-time plotting | 0.0001 g readability, software-linked |
| Stability studies and validation | Audit trail, CFR 21 Part 11 compliance, auto-cal | Regulated model with backup log |
For labs preparing HPLC vials, units must support programmable drying curves and quick logging of sample IDs for traceability. Moisture readings here must be tightly linked with solution standardisation and documentation trails for audit submission.
Moisture Analyser Use in HPLC and GC Sample Workflows
In chromatography, trace moisture can disrupt baseline and peak consistency, especially in GC vials where volatile analytes compete with residual water, causing ghost peaks or signal loss.
To prevent this:
- Check lyophilised samples for moisture before reconstitution.
- Ensure that solvents such as acetonitrile and methanol are dry and properly stored.
- Scan freeze-dried standards with a moisture analyser before dilution.
- Many labs include this in SOPs to maintain assay and stability accuracy over time.
Impact on Stability Studies and Batch Release
Moisture significantly affects product shelf life, particularly in semi-permeable packs or when hygroscopic materials are stored in amber vials. It can alter assay results over time.
Moisture analyser checkpoints are used in:
- Stability studies (real-time & accelerated)
- Packaging validation
- Injectable pre-fill calibration
- Granulation checks before tabletting
Results are logged with sample ID, timestamp, and method version under controlled conditions, using instruments with onboard or PC-linked data storage.
Maintenance and Cleaning
Moisture analysers require regular maintenance to prevent residue buildup, sensor drift, or pan warping. Wipe pans, run weekly blanks, clean chambers monthly, and adhere to part replacement schedules. Models like Borosil Scientific offer built-in alerts to reduce downtime.
Conclusion
Accurate moisture content determination is not just about what happens inside the analyser; upstream prep, drying protocols, and data consistency also shape it.
Moisture analysis plays a critical role from raw material evaluation to batch release. Investing in a programmable moisture analyser with built-in documentation tools, calibration traceability, and heating flexibility is essential for food, feed, pharmaceutical, analytical, and industrial workflows. With Borosil Scientific, you get precision backed by robust service support, validated performance, and a legacy of scientific trust.
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