DETERMINATION OF SERUM TRIGLYCERIDES BY MASS FRAGMENTOGRAPHY

A mass fragmentographic reference method for determination of human serum triglycerides is described. A fixed amount of a mixture of [1,1,2,3,3-2H5]glycerol tripalmitate and [1,1,2,3,3,-2H5]glycerol trioleate (500 nmol) is added to a fixed amount of serum (250 .mu.l) and extracted with chloroform/methanol (2:1 vol/vol). The triglycerides are isolated by means of TLC. The glycerol obtained after acid hydrolysis is converted into the tritrimethylsilyl derivative and the amount of unlabeled glycerol is determined from the ratio between the recordings at m/e 218 and m/e 222, obtained after analysis with a gas chromatograph-mass spectrometer equipped with a multiple ion detector. The 2 ions correspond to the peak at M-90 and M-91 in the mass spectrum of the tritrimethylsilyl derivative of unlabeled and (1,1,2,3,3-2H5)-labeled glycerol. The native SD of the method in the range 0.4-5.8 mmol/l was 2.4%. A fully enzymatic routine method for determination of triglycerides was compared with the mass fragmentographic reference method. There was a good correlation between the 2 methods (r = 0.995) and the regression coefficient was 1.19.