How to Choose a Moisture Analyzer: A Buyer's Guide for the UAE & GCC

Loss-on-drying (LOD) moisture analyzers: how they work

LOD moisture analyzers heat a sample on an integrated balance pan using a halogen heating element and measure the weight loss continuously until a stable endpoint is reached. The result is expressed as % moisture content (weight of water / original weight × 100). Modern halogen moisture analyzers using A&D Japan's Secondary Radiation Assist (SRA) technology achieve uniform heat distribution without hotspots, enabling reproducible results in 3–8 minutes for most sample types.

LOD is the most practical method for routine QC moisture determination in food, pharmaceuticals, chemicals, and building materials. It correlates well with reference oven drying methods (ISO 712, AOAC methods, BP/USP procedures) for most matrices. The key advantage is speed: where oven drying requires 1–24 hours, an LOD moisture analyzer returns a result in minutes.

Choosing the right resolution

A&D Japan's moisture analyzer range spans four resolution levels. The MS-70 (0.001% resolution, 0.001 mg balance) is the research-grade instrument for pharmaceutical QC and materials science where the last digit of moisture percentage is meaningful. The MX-50 (0.001% resolution, 0.1 mg balance) provides the same moisture resolution at lower cost, suitable for pharmaceutical production floor use. The MF-50 (0.01% resolution) covers most food industry and chemical QC applications. The ML-50 (0.1% resolution) is the entry-level screening instrument for routine production use.

Resolution selection should follow the same minimum sample weight logic as balance selection: the moisture percentage resolution you select must be appropriate for the moisture range you are measuring. For a product with 5–15% moisture, 0.01% resolution (MF-50) is more than adequate. For a hygroscopic API at 0.05–0.15% moisture, 0.001% resolution (MS-70 or MX-50) is required to detect meaningful variation.

When to use Karl Fischer titration instead

Karl Fischer (KF) titration is the gold standard for very low moisture content — typically below 0.1% — in liquids, gases, and samples that cannot be heated without degradation. KF measures total water content (free and bound) rather than loss-on-drying, making it more accurate for moisture-sensitive samples such as oils, solvents, and certain APIs. If your specification requires moisture below 0.1% in a temperature-sensitive product, KF titration is the required method, not LOD.

For most food, chemical, and routine pharmaceutical applications where moisture is above 0.1% and the sample tolerates heating at 50–200°C, LOD with a halogen moisture analyzer is faster, lower-cost, and easier to operate than KF titration. A&D Gulf can advise on the correct method for your specific application.

Drying temperature settings

Most halogen moisture analyzers allow drying temperature to be set between 50°C and 200°C. The correct setting depends on the sample matrix: food products typically dry at 105°C, pharmaceuticals at 105°C (USP ⟨731⟩) or method-specific temperatures, spices and volatile-rich samples at 80–90°C to avoid volatilising non-water components. A&D moisture analyzers support multiple saved drying programs, allowing different products to be tested without manual temperature entry.

Sample preparation: why results sometimes refuse to repeat

When a moisture analyzer gives scattered results, the instrument is rarely the cause — the sample is. The three rules that fix most repeatability complaints: use the same sample mass every time (the drying curve, and therefore the endpoint, changes with sample size); spread the sample in a thin, even layer across the whole pan rather than a heap in the centre (heaps dry on the outside and stay wet inside); and test immediately after sampling, because a sample left in Gulf summer air is already exchanging moisture with the room before the lid closes.

Matrix matters too. Free-flowing powders and granules are the easy case. Pastes, gels, and fatty samples skin over and trap moisture — spreading them thinly between glass-fibre sample sheets exposes more surface and stops spattering. Sugary foods can caramelise at standard temperatures, silently converting "moisture loss" into decomposition loss; drop the temperature and accept a longer test. If two operators get different numbers on the same product, write the sample mass, prep method, and temperature into a saved program and the numbers usually converge.

Verifying performance between calibrations

A moisture analyzer is two instruments in one — a balance and a heater — and both need periodic verification. The balance side is checked with an external calibration weight exactly like any other balance. The heating side is verified with a temperature calibration check against a calibrated reference, and overall performance is confirmed by running a moisture standard: sodium tartrate dihydrate, which releases a known percentage of water, is the accepted routine check. A result within tolerance on the standard is strong evidence the whole system — heating, weighing, and endpoint detection — is behaving.

For regulated environments, A&D Gulf provides combined balance and temperature calibration for A&D moisture analyzers from the JAFZA laboratory. Each certificate records the instrument and its serial number, the reference standards used, and the results obtained — see our ISO/IEC 17025 calibration guide for what a calibration certificate should contain.

Which model fits which application

Match the resolution tier to the decision the number has to support. The MS-70 is the research-grade choice where the third decimal place drives a release decision — pharmaceutical QC, fine chemicals, materials science, and low-moisture work that would otherwise need Karl Fischer. The MX-50 is the general laboratory and production-floor instrument. The MF-50 is the food-industry workhorse — grain, spices, snacks, dairy powders, bakery QC — and the ML-50 covers routine screening where the question is "is this batch roughly right?" rather than "exactly how dry is it?".

All four share the 400 W straight halogen lamp with A&D's Secondary Radiation Assist filter for even heating (the pan reaches 200 °C from ambient in about two minutes), saved drying programs, and RS-232C data output for records. All four are stocked and supported from JAFZA Dubai.

Where near-infrared (NIR) fits — and when it does not

NIR moisture measurement works on a completely different principle from loss-on-drying. Instead of heating a sample and weighing what evaporates, an NIR instrument shines near-infrared light at the product and measures how much is absorbed at the wavelengths water responds to. Nothing is destroyed, nothing is heated, and a reading takes seconds — which is why NIR is the technology used for continuous, in-line moisture measurement above a moving conveyor.

The catch is calibration. An NIR instrument does not measure moisture directly; it infers it from an optical signal, so it must be calibrated against a reference method — usually oven drying or loss-on-drying — separately for every product, and re-checked when a formulation, particle size or supplier changes. That makes NIR excellent for a high-volume line running one or two products continuously, and awkward for a QC laboratory testing twenty different materials a week.

For most UAE food, plastics and pharmaceutical QC work the practical answer is loss-on-drying: it measures mass loss directly, needs no product-specific calibration model, costs a fraction of an in-line NIR installation, and produces the kind of documented result an auditor recognises. NIR becomes worth considering when you need moisture data continuously rather than per sample, and when a single product runs long enough to justify building and maintaining its calibration. A&D's moisture line is loss-on-drying; if your application genuinely calls for in-line NIR, we would rather tell you that than sell you the wrong instrument.

What an auditor will actually ask for

A moisture result becomes audit evidence only if you can show three things: that the instrument was working, that the method was defined, and that the record is traceable to both. In practice that means a periodic calibration certificate for the balance side of the instrument, a documented verification routine run between calibrations, and a printed or exported result carrying date, time, operator and the drying programme used.

A&D builds for this. The MS-70/MX-50/MF-50/ML-50 range outputs to GLP, GMP, GCP and ISO formats over RS-232C, including date and time, ID, calibration data and check records — either to a PC or directly to the AD-8127 compact printer. A sodium tartrate dihydrate test sample (a stable 15.66% moisture reference) ships as standard for routine accuracy checks, and an optional certified temperature calibrator is available for the MS-70 and MX-50 where the drying temperature itself needs documented verification.

One nuance worth understanding before an audit: calibrating the weighing element and verifying the drying temperature are two different exercises. A balance calibration certificate says the instrument weighs correctly; it says nothing about whether the heater reaches the temperature it claims. For pharmaceutical and regulated food work, ask for both.