Phospholipids in amniotic fluid with special reference to the lecithin/sphingomyelin ratio.

At the present time, it appears that the method of choice for determination of phospholipids in amniotic fluid is the thin-layer chromatographic method. Noteworthy is that presented by Touchstone et al in which a minimum of effort is required. With the direct application of the amniotic fluid the problems of recovery and time-consuming efforts are minimized, considering that extraction and chromatography are carried out on the same plate. Another approach to the problem is shown in the reports of Krauss et al. in which they showed that 24 samples can be accommodated on one plate. Sensitivity was obtained using 2,5-bis[5-tert.-butylbenzoxazolyl (2')] thiophene to form fluorescent derivatives. With development times of as little as 10 min this method has not yet been perfected for use with biological samples, but indicates that some future developments using high-performance thin-layer chromatography are perhaps coming.