Miyazaki H, Shirai E, Ishibashi M, Niizima K
J Chromatogr. 1978 May 11;152(1):79-86. doi: 10.1016/s0021-9673(00)85336-4.
A highly specific and sensitive method has been developed for the quantitative determination of berberine in human urine. In order to carry out the microdetermination of berberine by chemical ionization mass fragmentography, berberine was reduced with sodium borohydride in methanol to tetrahydroberberine and subjected to gas chromatography-mass spectrometry. Berberine concentrations as low as 1 ng/ml urine can be measured by this method, with [2H3]berberine chloride as an internal standard.
