Trimyristin

Acetonitrile (ACN, ultragradient grade for HPLC, min. 99.9%, Chemsolute) was from Th. Geyer (Renningen, Germany) and ammonium formate (NH 4 HCOO, for LC-MS) was from Fisher Scientific (Schwerte, Germany). tert-Butyl methyl ether (TBME, ≥ 99.8%, for HPLC, Chromasolv), formic acid (HCOOH, ~ 98%, for LC-MS), and iso-propanol (≥ 99.9%, LC-MS, Chromasolv) were obtained from Sigma-Aldrich (Steinheim, Germany) and ethanol (absolute, > 99.7%, gradient grade for HPLC, HiPerSolv Chromanorm) was purchased from VWR International (Bruchsal, Germany). Lauric acid, myristic acid, palmitic acid (PA), stearic acid, palmitoleic acid, oleic acid (all analytical standard grade, > 99.5%), 1-monolaurin, 1-monomyristin, 1-monopalmitin (1-MP), 1-monostearin, 1-monoolein (all ≥ 99%), 1,2-distearin (> 99%), 1,3-diolein (≥ 97%), trilaurin, trimyristin, tripalmitin (TP), tristearin, and triolein (all > 99%) were from Sigma-Aldrich.
, and 1,3-distearin (all > 99%) were purchased from Larodan (Malmö, Sweden). Nucleodur Gravity-SB C18 column (150 mm × 3 mm, 3 µm) was from Macherey-Nagel (Düren, Germany). Several E 471 emulsifiers (distilled MG and MG/DG emulsifiers) were provided from different producers.

The solvents used as eluents were iso-propanol, water and methanol (HPLC-MS grade; Fluka). A stock fatty acid solution was prepared in acetone (HPLC grade; Sigma-Aldrich), and stored at 4 °C in the dark. It contained lauric acid (0.21 µg/g), suberic acid (0.22 µg/g), azelaic acid (0.16 µg/g), myristic acid (0.16 µg/g), sebacic acid (0.17 µg/g), palmitic acid (0.19 µg/g), oleic acid (0.26 µg/g), linoleic acid (0.20 µg/g), linolenic acid (0.18 µg/g) and stearic acid (0.26 µg/g). This solution was used to derive the calibration curves in the concentration range 3-400 ng/g. The acids were purchased from Sigma-Aldrich (purity > 99%). A second standard mixture solution was prepared in isopropanol, containing the following commercial acylglycerols (all purity > 99%, Sigma-Aldrich, U.S.A.): monopalmitin (7.9 µg/g of mP), dipalmitin (7.0 µg/g of PP), trimyristin (8.0 µg/g of MMM), tripalmitin (10.0 µg/g of PPP), and tristearin (7.9 µg/g of SSS). For derivatization, 2-hydrazinoquinoline (HQ), triphenylphosphine (TPP, purity 99%), and 2,2'-dipyridyl disulfide (DPDS, purity 98%) were purchased from Sigma-Aldrich (USA); solutions of 70.20 µg/g HQ, 69.00 µg/g DPDS and 79.50 µg/g TPP were prepared in acetonitrile (LC-MS grade, Sigma Aldrich) and stored at 4 °C in the dark.