Evaluation of the mass detector for quantitative detection of triglycerides and fatty acid methyl esters

The mass detector, a light scattering detector for use with high-performance liquid chromatography systems, was studied in order to determine which factors might affect sensitivity and quantification in the determination of triglycerides and other lipid materials. The detector response was found to be non-linear for triglycerides. The sensitivity was not only affected by evaporation temperatures and atomiser inlet air pressures within the detector, but also by the mobile phase flow-rate, and its composition. Detection limits of less than 1 microgram were achieved for non-volatile, saturated triglycerides, by direct injection, and the reproducibility of responses was about +/- 6% with isocratic elution (excluding tributyrin which was too volatile to be quantified accurately), but somewhat greater (+/- 16%) with gradient elution.