Direct determination by high-performance liquid chromatography of sn-2 monopalmitin after enzymatic lipase hydrolysis

An alternative method to determine the sn-2 monopalmitin in infant formulas was developed and validated. This method offers many advantages over the t raditional methods. It follows the official method in the first steps, puri fication of the fat or oil through an alumina column, and subsequently the triglycerides are incubated with pancreatic lipase in order to obtain the s n-2 monoglycerides. In traditional methods the sn-2 monoglycerides are sepa rated by preparative thin-layer chromatography and then, the 2-monoglycerid es are converted into the corresponding fatty acid methyl esters and analys ed by gas chromatography. In our method, separation, quantification and ide ntification of the sn-2 monoglycerides were achieved by high-performance li quid chromatography with evaporative light-scattering detection. The detect ion limit (0.19 mug), quantification limit (0.38 mug), linearity range (r=0 .999, range 1-200 mug) and precision (SD=1.10) show the suitability of the proposed method. This method is faster, cheaper and simple and does not con sume large quantities of reagents and materials. (C) 2001 Elsevier Science B.V. All rights reserved.