Studies On Rapid Analysis Of Gikgolic Acid In Dietary Supplements Of Ginkgo Biloba By Chromatography And Mass Spectrometry

Ginkgo biloba is a traditional medicinal plant of China.It was reported that Ginkgo biloba kernels and leaves can improve the capacity of organism anoxic endurance and anti-fatigue,and postpone aging process because of the bioactive constituents extracted from Ginkgo biloba such as flavonol glycosides and terpene lactones.Nowadays,Ginkgo biloba kernels have been processed into canned products,comfits,powder,and so on,while Ginkgo biloba leaves were brewed with boiled water as green tea.However,ginkgolic acids in Ginkgo biloba possess allergenic,cytotoxic and mutagenic properties.Therefore,the total content of ginkgolic acids in commercial EGb has been restricted a maximum concentration of 5 and 10 mg/kg in the European and Chinese Pharmacopoeia,respectively.With respect to safety,the daily intake of Ginkgo biloba foods should not be excessive.Up to now,numerous researches focus on the ginkgolic acids in medicine,whereas minor in dietary supplements.Considering the safety of consumers,it is necessary to quantify the content of ginkgolic acids in bulk food of Ginkgo biloba rapidly and precisely.First,a novel method on basis of direct analysis in real time integrated with mass spectrometry(DART-MS)was established and applied into rapid determination of five ginkgolic acids in dietary supplements of Ginkgo biloba kernels.Instrument parameter settings were optimized to obtain high sensitive and accurate determination of ginkgolic acids: with the gas heater temperature 450 ? and the sample introduction speed 0.2 mm/s.The five ginkgolic acids produced high intensity of [M-H]-in the negative ion mode by utilization of high purity helium gas,analyzed 2 ?L of solution after solvent evaporated to dryness.The calibration was linear over the range of 2-50 mg/L,with a correlation coefficient r ?0.998.The limit of detection was 0.5 mg/L,when relative standard deviation(n=6)was from 12.5% to 13.7%.Respectively,the contents of five ginkgolic acids in Ginkgo biloba leaves,Ginkgo biloba kernels and powder drink of Ginkgo biloba kernels were 4799.4±545.3 mg/kg,67.4±10.9 mg/kg and 26.6±2.3 mg/kg,identified by standard samples combined with the characteristic fragment ions.The results of DART-MS were in good agreement with those observed by thermochemolysis-gas chromatography.Recoveries of ginkgolic acids ranged 63.8%-71.2% for the spiked powder of Ginkgo biloba kernels.Furthermore,the DART-MS method dispenses with time-consuming pretreatments and consumedly shortens the analysis time.The proposed method can be applied in the high throughput screening,rapid qualification and semi-quantification for ginkgolic acids in food.In order to develop a simple and sensitive method on the rapid quantification of ginkgolic acids in Ginkgo biloba,thermochemolysis-gas chromatography(TMC-GC)was established.Samples were extracted with methanol assisted with ultrasonic.On-line derivatization of 1.0 ?L Ginkgo biloba sample solution at 300 ? with 2.0 ?L trimethylsulfonium hydroxide(TMSH)allowed the analysis of methyl derivatives of ginkgolic acids.The calibration was linear over the range of 5-600 mg/L,with a correlation coefficient r=0.9994.The limit of detection was 1.8 mg/L,when relative standard deviations(n=6)were ranged from 2.4% to 2.6%.The content of ginkgolic acids in Ginkgo biloba kernels,powder drink of Ginkgo biloba kernels,Ginkgo biloba autumn tea and spring tea was ranged from 31.5 mg/kg to 1.89×104 mg/kg.What's more,the dissolution rate of ginkgolic acids brewing 90 min with boiling water of Ginkgo biloba autumn tea and spring tea was 16% and 12%,and the dissolution amout was 1.95 mg/g and 2.23 mg/g,respectively.Recoveries of GA13:0 was ranged from 87.1%-106.1% for the spiked powder drink of Ginkgo biloba kernels.Due to its speediness,sensitivty and accuracy in the analysis of ginkgolic acids,the TMC-GC method appears to be the choice for rapid screening of large quantities of dietary supplements,intergrated with the results of DART-MS.These results suggest that the DART-MS method is suitable for the high throughput screening and rapid semi-quantification for ginkgolic acids in dietary supplements of Ginkgo biloba,while the TMC-GC method demostrates significant potential in the application of precise quantification for quality control and safety assessment in the samples.