Applications of automated thermometric titrimetry in routine process and quality control of fats and oils

Význam tématu

Automated thermometric titrimetry has emerged as a powerful tool for routine quality control of fats and oils by enabling rapid, precise measurement of free fatty acid content and iodine value with minimal operator intervention. Its robustness in non-aqueous, colored or turbid media makes it ideal for industrial laboratories seeking high throughput and reliable results.

Cíle a přehled studie

The primary aim of the presented work was to adapt manual procedures for free fatty acid (FFA) and iodine value (IV) determination to a fully automated thermometric titration platform. Two common analytical targets in oil quality assessment were selected to illustrate the technique’s versatility and its agreement with established AOCS reference methods.

Použitá metodika a instrumentace

The automated system employed:

• 859 Titrotherm thermometric titrator
• 800 Dosino dosing unit with 10 mL burette
• 814 USB Sample Processor for automatic sample handling

For FFA analysis, liquefied oil sample (approx. 10 g) was weighed into a plastic cup along with 0.5 g paraformaldehyde. A 1:1 mixture of toluene and 2-propanol was added, followed by titration with 0.1 mol/L tetrabutylammonium hydroxide in 2-propanol. The thermometric endpoint, arising from endothermic depolymerization of paraformaldehyde, was detected automatically.

For iodine value determination, ca. 0.2 g of melted fat was dissolved in cyclohexane, then glacial acetic acid and mercuric acetate were added. Wijs’ solution (iodine monochloride) was predosed, allowed to react, and the liberated iodine was titrated thermometrically with standard sodium thiosulfate after addition of potassium iodide.

Hlavní výsledky a diskuse

Free fatty acid determinations down to 0.04 % FFA (as oleic acid) were completed in under 20 s with precision better than 0.01 % and excellent agreement with AOCS manual titrations. Iodine values across multiple vegetable fat samples matched reference titrations within experimental error (±0.2–1.1 g I2/100 g). The automated approach eliminated endpoint ambiguity, reduced operator bias, and maintained performance in challenging matrices.

Přínosy a praktické využití metody

The automated thermometric titrimetry workflow delivers:

• High throughput: analyses in under one minute per sample
• Minimal maintenance: non-contact thermometric probe requires no calibration or regeneration
• Robustness: effective in non-aqueous, colored or turbid solutions
• Data integration: automatic export of results to spreadsheets for QA/QC reporting

Budoucí trendy a možnosti využití

Future developments may include integration with process analytical technology (PAT) for real-time monitoring, extension to additional lipid parameters (e.g., peroxide value), miniaturization for micro-sample analysis, and coupling with robotic sample handling in high-volume production labs.

Závěr

Automated thermometric titrimetry offers a fast, accurate, and operator-independent solution for routine quality control of fats and oils, delivering results in excellent agreement with official methods while enhancing laboratory productivity and data reliability.

Reference

1. M. J. D. Carneiro, M. A. Feres Júnior and O. E. S. Godinho, Determination of the acidity of oils using paraformaldehyde as a thermometric endpoint indicator, Journal of the Brazilian Chemical Society, 13(5), 692–694 (2002).