Phospholipid quantification in dry films by ATR-FTIR spectroscopy

LAFFERRIERE, LE; ILLESCA PG; CIAN LD; FEMIA AL; SELENSCIG DA; NUÑEZ JL

San Javier, Tucumán

Congreso; . XLI Reunión Anual de la Sociedad Argentina de Biofísica; 2012

Sociedad Argentina de Biofísica

Solid Lipid Nanoparticles (SLN) and liposomes (LS) are currently prepared with natural or synthetic phospholipids (PL). Determination and quantification of the PL content on SLN or LS are usually performed by Barlett´s, Stewart´s or chromatographic methods. All these assays require several steps, previous treatments of samples and/or specific compounds, which result in tedious and/or time consuming techniques. Fourier Transform Infrared spectroscopy (FTIR) has been used to quantify PL in soybean oil and compared with Barlett´s method, yielding better results for sensitivity, accuracy and allowing a wider concentration range of analysis1,2. Attenuated Total Reflectance-FTIR (ATR-FTIR) is widely used to study dry films of different compounds in biological samples3. In order to avoid problems such as solvent interferences, insolubility and/or the mentioned above, we propose the quantification of PL by this method. Calibration curves were performed in the range of 0.1-1 mg with DOPC or a PL mixture representative of the PL proportion in egg yolk (75% of phophatidylcholine (PC), 15% of phosphatidylethanolamine, 6% of lysoPC and 4% of sphingomyelin). Egg yolk PL extract purity and composition was analyzed through TLC, GC-MS and UFLC. The results obtained by ATR-FTIR were compared with Barlett´s method. The former showed a wider range of linearity, higher sensitivity and reproducibility. To test the applicability of this method, we quantify PL in SLN, LS or PL extracts from egg yolk. As a conclusion, the proposed methodology is suitable, simple and fast for the study of synthetic or natural PL content in complex mixtures or biological samples.