Overview
EN ISO 1741:1994 (ISO 1741:1980) specifies a vacuum oven method for determining the loss in mass on drying (moisture-related mass loss) of dextrose, applicable to both anhydrous dextrose and dextrose monohydrate. The procedure dries a measured test portion at 100 °C and at a pressure not exceeding 135 mbar, then expresses the loss as a percentage of the product mass.
Key topics and requirements
- Scope: Applicable to anhydrous and monohydrate dextrose only.
- Test temperature and pressure: Drying at 100 °C ±1 °C and pressure ≤ 135 mbar (vacuum oven).
- Test portion sizes: About 10 g for anhydrous dextrose and about 5 g for d‑monohydrate.
- Sample and dish preparation:
- Pre-dry the metal or glass dish and lid at 100 °C for 1 hour, cool in a desiccator and weigh to 0.0002 g.
- Place test portion in the dish, fit lid and weigh before drying.
- Drying procedure:
- Place covered dish in vacuum oven, remove lid inside oven and dry for 4 hours, maintaining reduced pressure.
- Draw a slow stream of air through a drying train (silica gel column + gas scrubber with concentrated sulfuric acid) into the oven as pressure is restored after drying.
- Replace lid, cool in desiccator and reweigh.
- Instrumentation: Electrically heated vacuum oven with calibrated thermometer and absolute pressure gauge; suitable vacuum pump to reach ≤135 mbar; analytical balance with required readability.
- Calculations: Loss on drying (%) = 100 × (m1 − m2) / (m1 − m0), where m0 = dish mass, m1 = dish + sample before drying, m2 = dish + sample after drying. Report the arithmetic mean of two determinations.
- Quality notes: If sample yellowing occurs, repeat at a lower temperature and document this in the report. Include all operating conditions and deviations in the test report.
Applications and users
- Routine quality control and specification testing in:
- Sugar and glucose syrup manufacturers
- Starch and derived-products industries
- Food ingredient suppliers and food labs
- Regulatory and compliance testing for product labelling, shelf‑life and moisture specification.
- Analytical and contract testing laboratories performing moisture analysis, loss on drying, and dehydration assessments for dextrose.
Related standards
- ISO 1741-1980 is the original International Standard; EN ISO 1741:1994 represents CEN adoption. Laboratories should reference this standard when validating vacuum oven loss-on-drying methods for dextrose products.
Keywords: EN ISO 1741:1994, dextrose, loss in mass on drying, vacuum oven method, moisture analysis, anhydrous dextrose, dextrose monohydrate, 100 °C, 135 mbar, quality control.
