Soy lecithin phospholipid determination by Fourier transform infrared spectroscopy and the acid digest/arseno-molybdate method: a comparative study

• Published in: Journal of the American Oil Chemists' Society 1999-01, Vol.76 (1), p.61-66
• Main Authors: Nzai, J.M. (University of Arkansas, Fayetteville, AR.), Proctor, A
• Format: Article
• Language: English
• Subjects: Bartlett method; Biological and medical sciences; Coefficients; Comparative studies; Food industries; Fourier analysis; Fourier transform infrared spectroscopy; Fourier transforms; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; GLYCINE MAX; Infrared analysis; Infrared spectroscopy; Lecithin; LECITHINE; LECITHINS; LECITINAS; Low concentrations; Molybdate; PHOSPHATIDYLCHOLINES; phospholipid analysis; Phospholipids; Phosphorus; Spectrum analysis; Variance analysis
• ISSN: 0003-021X; 1558-9331
• DOI: 10.1007/s11746-999-0048-9

A study was conducted to determine the accuracy and precision of phospholipid analysis by a simple Fourier transform infrared spectroscopy (FTIR) method relative to the conventional phospholipid phosphorus analysis by the acid digest/arseno‐molybdate method by Bartlett. Commercial soy lecithins of known concentrations of phospholipid were prepared and the phospholipid content measured by the FTIR and Bartlett methods. The coefficients of determination and of variances using the two methods were determined. The coefficient of determination for the FTIR method was >0.976 while that for the Bartlett method was ∼0.821. The coefficients of variances (CV) for 1–20% phospholipid concentration range using 10 replicate samples were found to lie between 3.59 and 9.45% for the FTIR method, while the Bartlett method had much higher CV for the same range and replicates (8.95 to 48.73%), signifying the higher accuracy and precision of the FTIR compared to the Bartlett method in the determination of the actual percentage of phospholipid. The Bartlett method gave no significant difference in the phospholipid levels at smaller concentrations, indicating its limitation in accurately determining percentage phospholipid of samples at low concentrations. The one‐way analysis of variance at the 1–20% phospholipid concentration range showed that there were significant differences in the mean percentage phospholipid levels for the FTIR data, which was therefore able to distinguish samples with small differences in phospholipid levels. The FTIR method gave consistently reliable results within the range chosen (1–20% phospholipid content). FTIR is a fast, simple, and reliable analytical tool for quantitative phospholipid analysis.