The use of solid 13C nuclear magnetic resonance for the characterization of cholesterol and bilirubin pigment composition of human gallstones

The new magic-angle spinning and cross polarization techniques for obtaining a 13C solid NMR spectrum are applied to the characterization of human cholesterol, mixed cholesterol-pigment, calcium bilirubinate and bilirubin pigment gallstones. The stones divide into two general classes: the cholesterol stones and the bilirubin pigment stones. The cholesterol stones are very similar to each other whereas the bilirubin pigment stones exhibit considerably more variation in spectral features. The importance of other material and polymerization in the bilirubin pigment stones is discussed.