Fatty acid diesters of long-chain 1,2-diols (1,2-DDE), or type II wax diesters, were analyzed in the vernix caseosa of a newborn girl. 1,2-DDE were isolated from the total lipid extract by the semipreparative TLC using plates coated with silica gel. Chromatographic separation of the 1,2-DDE molecular species was achieved on the non-aqueous reversed-phase HPLC with two Nova-Pak C18 columns connected in series (a total length of 45cm) and using an acetonitrile-ethyl acetate gradient. 1,2-DDE eluted from the column in the order of their equivalent chain number. The analytes were detected as ammonium adducts by an ion-trap mass spectrometer equipped with an atmospheric pressure chemical ionization source. Their structures were elucidated using tandem mass spectrometry with MS, MS(2) and MS(3) steps in a data-dependent mode. More than two thousand molecular species of 1,2-DDE were identified in 141 chromatographic peaks. The most abundant 1,2-DDE were monounsaturated lipids consisting of a C22 diol and a C18:1 fatty acid together with C16:0, C14:0 or C15:0 fatty acids. The positions of double bonds were characterized by the fragmentation of [M+C3H5N](+) formed in the ion source.

Department of Analytical Chemistry Faculty of Science Charles University Prague Hlavova 2030 8 CZ 128 43 Prague 2 Czech Republic

Department of Obstetrics and Gynaecology General Faculty Hospital and 1st Faculty of Medicine Charles University Prague Apolinářská 18 CZ 128 00 Prague 2 Czech Republic

Institute of Organic Chemistry and Biochemistry v v i Academy of Sciences of the Czech Republic Flemingovo nám 2 CZ 166 10 Prague 6 Czech Republic

Joachim Barrande Grammar School Talichova 824 CZ 266 01 Beroun Czech Republic

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