Quantitative analysis of 1‐stearoyl‐2‐oleoyl‐ sn ‐glycero‐3‐phosphoserine by negative‐ion fast‐atom bombardment mass spectrometry

Negative‐ion fast‐atom bombardment mass spectrometry was evaluated as a means for quantitative analysis of individual molecular species of glycerophosphatidylserine (GPS). With 200 ng of 1,2‐dipalmitoyl‐ sn ‐glycero‐3‐phosphoserine (GPS di 16:0) as an internal standard, the calibration curve for 1‐stearoyl‐2‐oleoyl‐ sn ‐glycero‐3‐phosphoserine (GPS 18:0–18:1) was linear over a range of 50–1000 ng (signal‐to‐noise ratio >4), with a correlation coefficient of 0.998. When the curve was derived from a mixture of GPS molecular species, only a slight variation in the ion intensity ratio of GPS 18:0–18:1 to GPS di 16:0 occurred. The method provides the possibility of quantifying GPS 18:0–18:1 among GPS species in the low nanogram range.