Non-aqueous reversed-phase liquid-chromatography of tocopherols and tocotrienols and their mass spectrometric quantification in pecan nuts

An easy and effective analytical method was developed for the simultaneous quantification of four tocopherols (Ts) and four tocotrienols (T3s) in three pecan nut cultivars (Stuart, Sioux, and Pawnee). The analytes were separated on a C30 column kept at 15 °C, under isocratic non-aqueous reversed-phase (NARP) conditions, in only 18 min and detected by atmospheric pressure chemical ionization-tandem mass spectrometry (APCI-MS/MS). The HPLC-APCI-MS/MS method was validated, according to the main FDA guidelines, and then applied for the characterization of the real samples. Analytes were extracted by cold saponification with recoveries greater than 87%. The limits of detection (LOD) and limits of quantification (LOQ) were in the range of 0.3-10 μg/100 mg and 1-30 μg/100 mg, respectively. Compared to other nuts, vitamin E composition of pecan nuts (Carya illinoinensis) has only partially been elucidated. Results have evidenced the prevalence of γ-forms for both Ts and T3 s and clear quantitative differences of the identified vitamers among the studied cultivars. The richest variety in vitamin E was Sioux with a total content of about ∼ 32 mg/100 g wet weight, followed by Stuart (∼16 mg/100 g) and Pawnee (∼9 mg/100 g).