2 2 dimethoxypropane dmp

Ascorbic acid was obtained from Sanchun Chemical Co. (Gyeonggi-Do, Korea); sulfuric acid (H₂SO₄) and sodium sulfate anhydrous were purchased from Daejung Chemical and Materials Co., Ltd. (Gyeonggi-Do, Korea); potassium hydroxide (KOH) was obtained from Junsei (Tokyo, Japan). Genuine chemical standards (STDs), such as TOC homologs (α-, β-, γ-, δ-forms), 37 standard fatty acid methyl esters mixture (FAME, CRM47885), and pentadecanoic acid (C15:0, P6125) were obtained from Sigma-Aldrich, Korea. Analytical or high-performance liquid chromatography-grade solvents were used for extraction and derivatization of TOCs and FA in milk samples of interest. Methanol, ethanol, and isooctane were obtained from Fisher Scientific Korea, Ltd. (Seoul, Korea). Benzene and heptane were purchased from Junsei (Tokyo, Japan), hexane was obtained from J.T. Baker (Phillipsburg, NJ, USA), and 2,2-dimethoxypropane (DMP) and dichloromethane were procured from Sigma-Aldrich Korea (Seoul, Korea).

Isooctane, benzene, heptane, and methanol were purchased from Fisher Scientific Korea Ltd. (Seoul, Korea) or Junsei Chemical Ltd. (Tokyo, Japan). Standards of a 37-fatty acid methyl ester (FAME) mixture (CRM47885), pentadecanoic acid (C15:0, P6125), sulfuric acid (H₂SO₄), dimethyl sulfoxide, 2,2-dimethoxypropane (DMP), and dichloromethane were purchased from Sigma-Aldrich Co. (St. Louis, MO, USA).