Ammoniac

Salmon lecithin was obtained by enzymatic hydrolysis in our laboratory, as described before [23 (link)]. Lipidic fractions were extracted by a low temperature enzymatic process that is solvent-free. The following materials were used in the present study: acetonitrile and diethyl ether (Sigma-Aldrich, Lyon, France), boron trifluoride-methanol (BF3) (Supelco, Bellfonte, PA, USA), chloroform (VWR-Prolabo, Milan, Italy), hexane, methanol, and formic acid (Carlo-Erba, Peypin, France), and ammoniac (Merck KGaA, Darmstadt, Germany). All of the organic solvents used were analytical grade reagents.

CSF and plasma samples were analyzed with an Agilent 7500ce inductively coupled plasma mass spectrometer (Agilent Technologies, Waldbronn, Germany). The instrument uses a collision/reaction cell with hydrogen for selenium (Se) determination, and helium for zinc (Zn) and Mn. Briefly, after ionization of plasma or CSF samples in the plasma torch and elimination of interference in the collision/reaction cells, element concentrations were determined by mass spectrometry, as previously reported [26 (link), 27 ]. Hemolysed plasma samples were excluded to avoid blood contamination that can significantly increase Zn and Mn values.
Plasma samples preparation: 25 μL of plasma samples were diluted (1:40; V:V) in 25 μL of distilled water and 950 μL of a solution containing 0.7 mmol/L EDTA (Merck, Darmstadt, Germany), 0.07% Triton-X-100 (Merck), 2% butanol, 0.5% ammoniac (Merck) and germanium as internal standard (Merck).
CSF samples preparation: 50 μL of CSF samples were diluted (1:20; V: V) in a 2% nitric solution and 10 μg/L of germanium as internal standard (Merck).