UHPLC-ESI-MS/MS for the Quantification of Eight Major Gingerols and Shogaols in Ginger Products: Effects of Ionization Polarity and Mobile Phase Modifier on the Sensitivity.

We developed and validated an improved ultra high performance liquid chromatography (UHPLC)-electrospray ionization (ESI)-tandem mass spectrometry (MS/MS) method for the fast separation and quantification of 8 major gingerols and shogaols (4-, 6-, 8-, 10-, and 12-gingerols, and 6-, 8-, and 10-shogaols) in gingerol products. The ionization polarity and mobile phase modifier greatly affected the mass ion profiles and sensitivity of the analytes. A mobile phase modifier of 0.05 mM ammonium formate dramatically decreased the sodium adduct ions and greatly increased the protonated ions of the gingerols and shogaols. Positive ion UHPLC-MS/MS with the ammonium formate in mobile phase showed greatly higher (4.5- to 15.7-fold) sensitivities than negative ion UHPLC. The positive ion UHPLC-MS/MS method showed excellent linearities (r(2) > 0.999), low limits of detection (LOD = 2.5 to 8.2 pg), high accuracy and precision, and no considerable matrix effect. Baseline separation of the 8 target compounds was achieved in 1 min by the UHPLC with a short C18 core-shell column. The method was successfully applied to analyze the compounds in fresh and dried powdered gingers, and dietary supplements. The total contents of the major compounds in the fresh gingers, dried powdered gingers, and dietary supplements were in the range of 1114 to 1478, 4380 to 11324, and 2915 to 29998 mg/kg, respectively. There was about 10-fold variation of the content in the dietary supplements with the commercial brands. This represents the 1st report on the ionization polarity and mobile phase modifier on the sensitivity of gingerols and shogaols in LC-mass spectrometry. Furthermore, the established method provided great improvement in chromatographic separation of the target gingerols.