Fluorescence micelle assay (FMA)
FMA was used to determine the concentration of PS in the samples. The FMA reagent contains 0.15 M sodium chloride, 0.05 M Tris, 5% ACN, 5 μM N -phenyl-1-naphtylamine and 15 ppm (parts per million) Brij35 with a pH 8.0. 10 µl of sample was mixed with 240 µl of FMA reagent in a 96 well plate (Greiner Bio-One, Monroe, USA) and shaken for 60 sec at 35oC. The fluorescence detector, Tecan Spark (Tecan, Mannedorf, Switzerland) was set to an excitation wavelength of 350 nm and an emission wavelength of 420 nm. For quantitation, a calibration curve ranging from 0.1mg/ml to 0.6 mg/ml PS was used as standard.