UHPLC−MS Analysis of Ginkgo Products. A published UHPLCMS method29 was used for the simultaneous analysis of sesquiterpene lactones and flavonoids from various ginkgo products to confirm the presence of G. biloba leaf extracts in the botanical dietary supplements.This method involved the use of [M + H]+ ions of five sesquiterpene lactones and three flavonoids which were observed at m/z 425.2 (ginkgolide J, ginkgolide B), m/z 441.2 (ginkgolide C), m/z 327.3
(bilobalide), m/z 409.2 (ginkgolide A), m/z 303.1 (quercetin), m/z 287.1 (kaempferol), and m/z 317.1 (isorhamnetin). The compound identification was based on retention times and MS in comparison with standard compounds.
Ozonolysis. The double bond positions in the C15:1 and C17:1 standards were determined by standard ozonolysis procedures. Each individual C15:1 and C17:1 standard (1.0 mg/mL) was derivatized as described in the sample preparation section. The standard solution was dried. The residue was dissolved in 0.5 mL of methylene chloride.Ozone used for the reaction was generated using a Triozone generator and bubbled through the solution at −78 °C until a blue color was observed indicating ozone saturation. The reaction mixture was stirred for 4 h and then quenched by addition of dimethyl sulfide (200 μL). The solution allowed to warm to room temperature before analyzed by
GC/MS using the method described previously.
UHPLC−MS Analysis of Ginkgo Products. A published UHPLCMS method29 was used for the simultaneous analysis of sesquiterpene lactones and flavonoids from various ginkgo products to confirm the presence of G. biloba leaf extracts in the botanical dietary supplements.This method involved the use of [M + H]+ ions of five sesquiterpene lactones and three flavonoids which were observed at m/z 425.2 (ginkgolide J, ginkgolide B), m/z 441.2 (ginkgolide C), m/z 327.3(bilobalide), m/z 409.2 (ginkgolide A), m/z 303.1 (quercetin), m/z 287.1 (kaempferol), and m/z 317.1 (isorhamnetin). The compound identification was based on retention times and MS in comparison with standard compounds.Ozonolysis. The double bond positions in the C15:1 and C17:1 standards were determined by standard ozonolysis procedures. Each individual C15:1 and C17:1 standard (1.0 mg/mL) was derivatized as described in the sample preparation section. The standard solution was dried. The residue was dissolved in 0.5 mL of methylene chloride.Ozone used for the reaction was generated using a Triozone generator and bubbled through the solution at −78 °C until a blue color was observed indicating ozone saturation. The reaction mixture was stirred for 4 h and then quenched by addition of dimethyl sulfide (200 μL). The solution allowed to warm to room temperature before analyzed byGC/MS using the method described previously.
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