Recovery of various radiolabeled lipids into the lower chloroform phase after the phase separation.

The HEPES buffer, containing [³²P]Sph-1-P, [³H]LPA, [³H]Sph, [³H]C₆-Cer, or [¹⁴C]sphingomyelin (SM), and chloroform/methanol (1:2) were mixed without (▨) or with further addition of NH₄OH (■) or HCl (▪). The phases were then separated, and radioactivities of the lower phase were counted by liquid scintillation counting. The percentage of recovery of each radiolabeled lipid into the lower chloroform phase was calculated as 100 × the radioactivity in the lower chloroform phase/the radioactivity added.