Determination of phospholipids in soybean lecithin samples via the phosphorus monoxide molecule by high-resolution continuum source graphite furnace molecular absorption spectrometry

- HR-CS GF MAS was employed for indirect determination of phospholipids.
- Soybean lecithin samples were analyzed.
- Phosphorus was determined via molecular absorption of phosphorus monoxide.
- Simple sample preparation by dilution with MIBK.

This paper presents a method for determining phospholipids in soybean lecithin samples by phosphorus determination using high-resolution continuum source graphite furnace molecular absorption spectrometry (HR-CS GF MAS) via molecular absorption of phosphorus monoxide. Samples were diluted in methyl isobutyl ketone. The best conditions were found to be 213.561 nm with a pyrolysis temperature of 1300 °C, a volatilization temperature of 2300 °C and Mg as a chemical modifier. To increase the analytical sensitivity, measurement of the absorbance signal was obtained by summing molecular transition lines for PO surrounding 213 nm: 213.561, 213.526, 213.617 and 213.637 nm. The limit of detection was 2.35 mg g−1 and the precision, evaluated as relative standard deviation (RSD), was 2.47% (n = 10) for a sample containing 2.2% (w/v) phosphorus. The developed method was applied for the analysis of commercial samples of soybean lecithin. The determined concentrations of phospholipids in the samples varied between 38.1 and 45% (w/v).