Quantitative Determination of Total L-Carnitine in Infant Formula, Follow-up Formula, and Raw Materials by Liquid Chromatography with Tandem Mass Spectrometry

Isao NADAOKA, Emi HATAKEYAMA, Chihiro TANADA, Tasuku SAKAMOTO, Shinichi FUKAYA, Takashi AKIBA, Koichi INOUE, Yutaka YAMANO, Toshimasa TOYO^|^rsquo;OKA
2014 Analytical Sciences  
We developed a rapid and useful routine screening assay for total L-carnitine content in various infant formulas and materials by liquid chromatography coupled with a tandem mass spectrometric method (LC-MS/MS) and alkaline hydrolysis. For separation of L-carnitine, a multi-mode octadecylsilane (ODS) column was used that contained ODS ligands, anion ligands, and cation ligands to avoid using ion-pairing agents. The stable isotope L-carnitine-d3 (m/z 165 → 103/85) was used in electrospray MS/MS
more » ... n the multiple reaction monitoring mode with the ion transitions of m/z 162 → 103/85 for detection and quantitation of L-carnitine. Alkaline hydrolysis of short/medium chain (C2 -C15) acyl-Lcarnitines in infant formula was analyzed by LC with quadrupole time-of-flight mass spectrometry (QTOF-MS). The majority of short/medium chain acyl-L-carnitines were hydrolyzed to free L-carnitine. The overall standard deviations for L-carnitine in infant formula, follow-up formula and raw materials ranged from 2.1 to 4.0. The overall mean recoveries ranged from 90.2 to 94.2%. Fig. 1 Chemical structure of L-carnitine.
doi:10.2116/analsci.30.839 pmid:25109647 fatcat:h53u3pcrdjf4dbq5cdi2sxkufm