Lecithin—Sphingomyelin Ratio in Amniotic Fluid, as Assessed by a Modified Thin-Layer Chromatographic Method in Which a Commercial Pre-Coated Plate Is Used

[摘要] Commercially available pre-coated thin-layer chromatographic plates consisting of silica gel supported on aluminum sheets were used to determine the lecithinsphingomyelin ratio in samples of amniotic fluid. These lipids were separated in a chloroform-methanol-water (65:25:4 by vol) solvent system (lecithin, R F = 0.33; sphingomyelin, R F = 0.25), and the spots were made visible in 5-15 min by heating to 180 °C after spraying with a solution of copper acetate (30 g/liter) in aqueous phosphoric acid (80 g/liter). The lipids were measured densitometrically after "peeling off" the adsorbent containing the spots by using a transparent cellulose ("Scotch brand") adhesive tape. Virtues of the original Gluck procedure are retained without need to heat the plates to 280 °C after spraying with corrosive aqueous sulfuric acid (698 g/liter) to make the lipids visible. Resuits for synthetic mixtures in concentrations within the physiological range and with a ratio of 0.5 to 3.0 showed an accuracy of 99% ± 7% (SD).

[学科分类] 过敏症与临床免疫学