Study On Chromatography-Mass Spectrometric New Methods For The Analysis Of Policosanol

Policosanol(PC)is the main aliphatic primary alcohols in tobacco.PC reportedly possesses various beneficial functionalities including improving muscle endurance,prevention of cardiovascular diseases,reduction of platelet aggregation and endothelial damage,lipid-lowering activity,reduction of blood cholesterol level,and antioxidant activity.PC is the major constituents of the principal PAH-producing fractions.The accurate quantifications of PC are necessary to evaluate its impact on the public health.Methods of PCs determination are concentrated in bee wax,rice bran and vegetable oils sample,hower reports concerning the detection of PCs in tobacco,especially for the simultaneous determination of PCs are very few.The detection methods of PCs are commonly gas chromatography(GC)and gas chromatography-tandem mass chromatography.In recent years,high performance liquid chromatography(HPLC),especially high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS)for wide usage and high sensitivity,good repeatability are widely used in real samples analysis.1.A method for the determination of PC was developed using a liquid-liquid extraction-GC-MS-internal standard method in tobacco,by using internal standard calibration,comparing the extraction efficiency of different solvent system and the analysis of the instrument conditions are optimized,eventually we established a rapid detetion method of PC in tobacco.The analytes were detected by MS in electron ionization mode(El)and selcected ion monitoring(SIM)mode.Internal standard method was employed to quantify.The results indicated that the average spiked recoveries of PC were 92.4%～103.3%,the intra-day and the inter-day relative standard deviations(RSDs)were 0.78%～3.47%(n=6)and 1.75%～5.76%(n=6),respectively,and the LOQs(S/N =10)were 0.27～0.48 μg/mL.The method was simple with high stability,good reproducibility,and suitable for the simultaneously determination of many PC in tobacco.2.A method was developed for simultaneous determination of policosanol in tobacco by pre-column derivatization and high performance liquid chromatography-triple quadrupole mass spectrometry(HPLC-MS/MS).Using diphenic anhydride as pre-column derivatization reagent,the stable derivative of policosanol was obtained at 60 ℃ for 80 min with pyridine.In order to enhance the sensitivity,the derivatization was optimized regarding amount and temperature of diphenic anhydride.Aiming at the chemical properties and sample impurities of the target,the parameters such as chromatography conditions,mass spectrum conditions and types of extraction were optimized.LOD was 0.3～0.4 ng/mL,and the LOQ was 1.2～1.4 ng/mL.The PC were analyzed under the multiple reaction monitoring(MRM)mode with negative electrospray ionization(ESI-).Under the optimal conditions,the internal standard method was used to quantify the contents of the 4 PC.The recovery(n=6)ranged from 88.7%～102.1%with relative standard deviations from 1.7%～5.5%.This method had good linearity,precision and recovery,and showed obvious advantages such as sensitivity and low matrix effect comparing to the previously reported pre-column derivatization GC-MS methods.3.Firstly,Fe3O4/SiO2 nanoparticles modified with polymer monolithic column was prepared by in situ polymerization and used as stationary phases for GC,of which divinylbenzene(DVB)as the monomer,toluene and dodecanol as the binary porogenic solvent,2,2’-azobisisobutyronitrile(AIBN)as the initiator.Different ratios of porogens and Fe3O4/SiO2 nanoparticles were used for optimizing the properties of monolithic column.The as prepared monolithic columns were characterized by scanning electronmicroscopy,nitrogen adsorption-desorption,and Fourier transform infrared spectroscopy,respectively.The main factors affecting the porous structure,the mechanical stability of the monolith was investigated.The results show that the column has good mechanical tolerance.The monolith was then applied for the evaluation of gas chromatography separation properties.Here,Electromagnetic induction heating technique was performed for column temperature rising with the thermal effect of eddy current in ferromagnetic materials Fe3O4.The monolith offer good separation efficiency for benzene and toluene and a higher column efficiency was obtained up to 4481 and 9216 plates per meter,respectively.In addition,the injection volume and column capacity of proposed system is as much as 5 μL and 100 ng.The fabricated Fe3O4@SiO2 nanoparticles incorporated poly(Divinylbenzene)monolithic column have been shown to be very promising for the gas chromatography separation.4.The novel monolithic column was used as the separation medium by coupling with GCC-FID for the determination of PC in tobacco.The functionalized polymer monolith material was characterized by SEM and nitrogen adsorption-desorption.The experimental results showed that this type of polymer possess a good network skeleton structure.Under the optimized conditions,the LOD and LOQ were determined in the range of 0.12～0.17 and 0.40～0.57 μg/mL-1,respectively.The intraday and interday precisions of the target PC were determined to be in the range of 4.5%～7.0%and 4.8～8.3%,respectively.Satisfactory recoveries were obtained in the range of 84.8%～98.5%,exhibiting that the present method is effective for the determination of PC in tobacco.